Merge branch 'js/c-merge-recursive'
authorJunio C Hamano <junkio@cox.net>
Mon, 28 Aug 2006 03:18:58 +0000 (20:18 -0700)
committerJunio C Hamano <junkio@cox.net>
Mon, 28 Aug 2006 03:33:46 +0000 (20:33 -0700)
* js/c-merge-recursive: (21 commits)
  discard_cache(): discard index, even if no file was mmap()ed
  merge-recur: do not die unnecessarily
  merge-recur: try to merge older merge bases first
  merge-recur: if there is no common ancestor, fake empty one
  merge-recur: do not setenv("GIT_INDEX_FILE")
  merge-recur: do not call git-write-tree
  merge-recursive: fix rename handling
  .gitignore: git-merge-recur is a built file.
  merge-recur: virtual commits shall never be parsed
  merge-recur: use the unpack_trees() interface instead of exec()ing read-tree
  merge-recur: fix thinko in unique_path()
  Makefile: git-merge-recur depends on xdiff libraries.
  merge-recur: Explain why sha_eq() and struct stage_data cannot go
  merge-recur: Cleanup last mixedCase variables...
  merge-recur: Fix compiler warning with -pedantic
  merge-recur: Remove dead code
  merge-recur: Get rid of debug code
  merge-recur: Convert variable names to lower_case
  Cumulative update of merge-recursive in C
  recur vs recursive: help testing without touching too many stuff.
  ...

This is an evil merge that removes TEST script from the toplevel.

.gitignore
Makefile
cache.h
git-merge.sh
git-rebase.sh
merge-recursive.c [new file with mode: 0644]
read-cache.c

index 55cd984..3da0e5e 100644 (file)
@@ -62,6 +62,7 @@ git-merge-tree
 git-merge-octopus
 git-merge-one-file
 git-merge-ours
+git-merge-recur
 git-merge-recursive
 git-merge-resolve
 git-merge-stupid
index d9741f9..a608476 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -196,6 +196,7 @@ PROGRAMS = \
        git-upload-pack$X git-verify-pack$X \
        git-pack-redundant$X git-var$X \
        git-describe$X git-merge-tree$X git-blame$X git-imap-send$X \
+       git-merge-recur$X \
        $(EXTRA_PROGRAMS)
 
 # Empty...
@@ -711,6 +712,11 @@ git-http-push$X: revision.o http.o http-push.o $(GITLIBS)
        $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
                $(LIBS) $(CURL_LIBCURL) $(EXPAT_LIBEXPAT)
 
+merge-recursive.o path-list.o: path-list.h
+git-merge-recur$X: merge-recursive.o path-list.o $(GITLIBS)
+       $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+               $(LIBS)
+
 $(LIB_OBJS) $(BUILTIN_OBJS): $(LIB_H)
 $(patsubst git-%$X,%.o,$(PROGRAMS)): $(LIB_H) $(wildcard */*.h)
 $(DIFF_OBJS): diffcore.h
@@ -870,7 +876,7 @@ check-docs::
        do \
                case "$$v" in \
                git-merge-octopus | git-merge-ours | git-merge-recursive | \
-               git-merge-resolve | git-merge-stupid | \
+               git-merge-resolve | git-merge-stupid | git-merge-recur | \
                git-ssh-pull | git-ssh-push ) continue ;; \
                esac ; \
                test -f "Documentation/$$v.txt" || \
diff --git a/cache.h b/cache.h
index ccb83a1..03d9dd0 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -145,6 +145,7 @@ extern void verify_non_filename(const char *prefix, const char *name);
 extern int read_cache(void);
 extern int read_cache_from(const char *path);
 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
+extern int discard_cache(void);
 extern int verify_path(const char *path);
 extern int cache_name_pos(const char *name, int namelen);
 #define ADD_CACHE_OK_TO_ADD 1          /* Ok to add */
index a9cfafb..d049e16 100755 (executable)
@@ -9,15 +9,20 @@ USAGE='[-n] [--no-commit] [--squash] [-s <strategy>]... <merge-message> <head> <
 LF='
 '
 
-all_strategies='recursive octopus resolve stupid ours'
-default_twohead_strategies='recursive'
+all_strategies='recursive recur octopus resolve stupid ours'
+case "${GIT_USE_RECUR_FOR_RECURSIVE}" in
+'')
+       default_twohead_strategies=recursive ;;
+?*)
+       default_twohead_strategies=recur ;;
+esac
 default_octopus_strategies='octopus'
 no_trivial_merge_strategies='ours'
 use_strategies=
 
 index_merge=t
 if test "@@NO_PYTHON@@"; then
-       all_strategies='resolve octopus stupid ours'
+       all_strategies='recur resolve octopus stupid ours'
        default_twohead_strategies='resolve'
 fi
 
@@ -117,6 +122,10 @@ do
                        strategy="$2"
                        shift ;;
                esac
+               case "$strategy,${GIT_USE_RECUR_FOR_RECURSIVE}" in
+               recursive,?*)
+                       strategy=recur ;;
+               esac
                case " $all_strategies " in
                *" $strategy "*)
                        use_strategies="$use_strategies$strategy " ;;
index 7d3a5d0..20f74d4 100755 (executable)
@@ -35,7 +35,13 @@ If you would prefer to skip this patch, instead run \"git rebase --skip\".
 To restore the original branch and stop rebasing run \"git rebase --abort\".
 "
 unset newbase
-strategy=recursive
+case "${GIT_USE_RECUR_FOR_RECURSIVE}" in
+'')
+       strategy=recursive ;;
+?*)
+       strategy=recur ;;
+esac
+
 do_merge=
 dotest=$GIT_DIR/.dotest-merge
 prec=4
@@ -200,6 +206,11 @@ do
        shift
 done
 
+case "$strategy,${GIT_USE_RECUR_FOR_RECURSIVE}" in
+recursive,?*)
+       strategy=recur ;;
+esac
+
 # Make sure we do not have .dotest
 if test -z "$do_merge"
 then
diff --git a/merge-recursive.c b/merge-recursive.c
new file mode 100644 (file)
index 0000000..048cca1
--- /dev/null
@@ -0,0 +1,1356 @@
+/*
+ * Recursive Merge algorithm stolen from git-merge-recursive.py by
+ * Fredrik Kuivinen.
+ * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
+ */
+#include <stdarg.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+#include "cache.h"
+#include "cache-tree.h"
+#include "commit.h"
+#include "blob.h"
+#include "tree-walk.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "run-command.h"
+#include "tag.h"
+#include "unpack-trees.h"
+#include "path-list.h"
+
+/*
+ * A virtual commit has
+ * - (const char *)commit->util set to the name, and
+ * - *(int *)commit->object.sha1 set to the virtual id.
+ */
+
+static unsigned commit_list_count(const struct commit_list *l)
+{
+       unsigned c = 0;
+       for (; l; l = l->next )
+               c++;
+       return c;
+}
+
+static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
+{
+       struct commit *commit = xcalloc(1, sizeof(struct commit));
+       static unsigned virtual_id = 1;
+       commit->tree = tree;
+       commit->util = (void*)comment;
+       *(int*)commit->object.sha1 = virtual_id++;
+       /* avoid warnings */
+       commit->object.parsed = 1;
+       return commit;
+}
+
+/*
+ * Since we use get_tree_entry(), which does not put the read object into
+ * the object pool, we cannot rely on a == b.
+ */
+static int sha_eq(const unsigned char *a, const unsigned char *b)
+{
+       if (!a && !b)
+               return 2;
+       return a && b && memcmp(a, b, 20) == 0;
+}
+
+/*
+ * Since we want to write the index eventually, we cannot reuse the index
+ * for these (temporary) data.
+ */
+struct stage_data
+{
+       struct
+       {
+               unsigned mode;
+               unsigned char sha[20];
+       } stages[4];
+       unsigned processed:1;
+};
+
+static struct path_list current_file_set = {NULL, 0, 0, 1};
+static struct path_list current_directory_set = {NULL, 0, 0, 1};
+
+static int output_indent = 0;
+
+static void output(const char *fmt, ...)
+{
+       va_list args;
+       int i;
+       for (i = output_indent; i--;)
+               fputs("  ", stdout);
+       va_start(args, fmt);
+       vfprintf(stdout, fmt, args);
+       va_end(args);
+       fputc('\n', stdout);
+}
+
+static void output_commit_title(struct commit *commit)
+{
+       int i;
+       for (i = output_indent; i--;)
+               fputs("  ", stdout);
+       if (commit->util)
+               printf("virtual %s\n", (char *)commit->util);
+       else {
+               printf("%s ", sha1_to_hex(commit->object.sha1));
+               if (parse_commit(commit) != 0)
+                       printf("(bad commit)\n");
+               else {
+                       const char *s;
+                       int len;
+                       for (s = commit->buffer; *s; s++)
+                               if (*s == '\n' && s[1] == '\n') {
+                                       s += 2;
+                                       break;
+                               }
+                       for (len = 0; s[len] && '\n' != s[len]; len++)
+                               ; /* do nothing */
+                       printf("%.*s\n", len, s);
+               }
+       }
+}
+
+static const char *current_index_file = NULL;
+static const char *original_index_file;
+static const char *temporary_index_file;
+static int cache_dirty = 0;
+
+static int flush_cache(void)
+{
+       /* flush temporary index */
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       int fd = hold_lock_file_for_update(lock, current_index_file, 1);
+       if (write_cache(fd, active_cache, active_nr) ||
+                       close(fd) || commit_lock_file(lock))
+               die ("unable to write %s", current_index_file);
+       discard_cache();
+       cache_dirty = 0;
+       return 0;
+}
+
+static void setup_index(int temp)
+{
+       current_index_file = temp ? temporary_index_file: original_index_file;
+       if (cache_dirty) {
+               discard_cache();
+               cache_dirty = 0;
+       }
+       unlink(temporary_index_file);
+       discard_cache();
+}
+
+static struct cache_entry *make_cache_entry(unsigned int mode,
+               const unsigned char *sha1, const char *path, int stage, int refresh)
+{
+       int size, len;
+       struct cache_entry *ce;
+
+       if (!verify_path(path))
+               return NULL;
+
+       len = strlen(path);
+       size = cache_entry_size(len);
+       ce = xcalloc(1, size);
+
+       memcpy(ce->sha1, sha1, 20);
+       memcpy(ce->name, path, len);
+       ce->ce_flags = create_ce_flags(len, stage);
+       ce->ce_mode = create_ce_mode(mode);
+
+       if (refresh)
+               return refresh_cache_entry(ce, 0);
+
+       return ce;
+}
+
+static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
+               const char *path, int stage, int refresh, int options)
+{
+       struct cache_entry *ce;
+       if (!cache_dirty)
+               read_cache_from(current_index_file);
+       cache_dirty++;
+       ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
+       if (!ce)
+               return error("cache_addinfo failed: %s", strerror(cache_errno));
+       return add_cache_entry(ce, options);
+}
+
+/*
+ * This is a global variable which is used in a number of places but
+ * only written to in the 'merge' function.
+ *
+ * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
+ *                       don't update the working directory.
+ *               0    => Leave unmerged entries in the cache and update
+ *                       the working directory.
+ */
+static int index_only = 0;
+
+static int git_read_tree(struct tree *tree)
+{
+       int rc;
+       struct object_list *trees = NULL;
+       struct unpack_trees_options opts;
+
+       if (cache_dirty)
+               die("read-tree with dirty cache");
+
+       memset(&opts, 0, sizeof(opts));
+       object_list_append(&tree->object, &trees);
+       rc = unpack_trees(trees, &opts);
+       cache_tree_free(&active_cache_tree);
+
+       if (rc == 0)
+               cache_dirty = 1;
+
+       return rc;
+}
+
+static int git_merge_trees(int index_only,
+                          struct tree *common,
+                          struct tree *head,
+                          struct tree *merge)
+{
+       int rc;
+       struct object_list *trees = NULL;
+       struct unpack_trees_options opts;
+
+       if (!cache_dirty) {
+               read_cache_from(current_index_file);
+               cache_dirty = 1;
+       }
+
+       memset(&opts, 0, sizeof(opts));
+       if (index_only)
+               opts.index_only = 1;
+       else
+               opts.update = 1;
+       opts.merge = 1;
+       opts.head_idx = 2;
+       opts.fn = threeway_merge;
+
+       object_list_append(&common->object, &trees);
+       object_list_append(&head->object, &trees);
+       object_list_append(&merge->object, &trees);
+
+       rc = unpack_trees(trees, &opts);
+       cache_tree_free(&active_cache_tree);
+
+       cache_dirty = 1;
+
+       return rc;
+}
+
+static struct tree *git_write_tree(void)
+{
+       struct tree *result = NULL;
+
+       if (cache_dirty) {
+               unsigned i;
+               for (i = 0; i < active_nr; i++) {
+                       struct cache_entry *ce = active_cache[i];
+                       if (ce_stage(ce))
+                               return NULL;
+               }
+       } else
+               read_cache_from(current_index_file);
+
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+
+       if (!cache_tree_fully_valid(active_cache_tree) &&
+                       cache_tree_update(active_cache_tree,
+                               active_cache, active_nr, 0, 0) < 0)
+               die("error building trees");
+
+       result = lookup_tree(active_cache_tree->sha1);
+
+       flush_cache();
+       cache_dirty = 0;
+
+       return result;
+}
+
+static int save_files_dirs(const unsigned char *sha1,
+               const char *base, int baselen, const char *path,
+               unsigned int mode, int stage)
+{
+       int len = strlen(path);
+       char *newpath = malloc(baselen + len + 1);
+       memcpy(newpath, base, baselen);
+       memcpy(newpath + baselen, path, len);
+       newpath[baselen + len] = '\0';
+
+       if (S_ISDIR(mode))
+               path_list_insert(newpath, &current_directory_set);
+       else
+               path_list_insert(newpath, &current_file_set);
+       free(newpath);
+
+       return READ_TREE_RECURSIVE;
+}
+
+static int get_files_dirs(struct tree *tree)
+{
+       int n;
+       if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
+               return 0;
+       n = current_file_set.nr + current_directory_set.nr;
+       return n;
+}
+
+/*
+ * Returns a index_entry instance which doesn't have to correspond to
+ * a real cache entry in Git's index.
+ */
+static struct stage_data *insert_stage_data(const char *path,
+               struct tree *o, struct tree *a, struct tree *b,
+               struct path_list *entries)
+{
+       struct path_list_item *item;
+       struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
+       get_tree_entry(o->object.sha1, path,
+                       e->stages[1].sha, &e->stages[1].mode);
+       get_tree_entry(a->object.sha1, path,
+                       e->stages[2].sha, &e->stages[2].mode);
+       get_tree_entry(b->object.sha1, path,
+                       e->stages[3].sha, &e->stages[3].mode);
+       item = path_list_insert(path, entries);
+       item->util = e;
+       return e;
+}
+
+/*
+ * Create a dictionary mapping file names to stage_data objects. The
+ * dictionary contains one entry for every path with a non-zero stage entry.
+ */
+static struct path_list *get_unmerged(void)
+{
+       struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
+       int i;
+
+       unmerged->strdup_paths = 1;
+       if (!cache_dirty) {
+               read_cache_from(current_index_file);
+               cache_dirty++;
+       }
+       for (i = 0; i < active_nr; i++) {
+               struct path_list_item *item;
+               struct stage_data *e;
+               struct cache_entry *ce = active_cache[i];
+               if (!ce_stage(ce))
+                       continue;
+
+               item = path_list_lookup(ce->name, unmerged);
+               if (!item) {
+                       item = path_list_insert(ce->name, unmerged);
+                       item->util = xcalloc(1, sizeof(struct stage_data));
+               }
+               e = item->util;
+               e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
+               memcpy(e->stages[ce_stage(ce)].sha, ce->sha1, 20);
+       }
+
+       return unmerged;
+}
+
+struct rename
+{
+       struct diff_filepair *pair;
+       struct stage_data *src_entry;
+       struct stage_data *dst_entry;
+       unsigned processed:1;
+};
+
+/*
+ * Get information of all renames which occured between 'o_tree' and
+ * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
+ * 'b_tree') to be able to associate the correct cache entries with
+ * the rename information. 'tree' is always equal to either a_tree or b_tree.
+ */
+static struct path_list *get_renames(struct tree *tree,
+                                       struct tree *o_tree,
+                                       struct tree *a_tree,
+                                       struct tree *b_tree,
+                                       struct path_list *entries)
+{
+       int i;
+       struct path_list *renames;
+       struct diff_options opts;
+
+       renames = xcalloc(1, sizeof(struct path_list));
+       diff_setup(&opts);
+       opts.recursive = 1;
+       opts.detect_rename = DIFF_DETECT_RENAME;
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       if (diff_setup_done(&opts) < 0)
+               die("diff setup failed");
+       diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
+       diffcore_std(&opts);
+       for (i = 0; i < diff_queued_diff.nr; ++i) {
+               struct path_list_item *item;
+               struct rename *re;
+               struct diff_filepair *pair = diff_queued_diff.queue[i];
+               if (pair->status != 'R') {
+                       diff_free_filepair(pair);
+                       continue;
+               }
+               re = xmalloc(sizeof(*re));
+               re->processed = 0;
+               re->pair = pair;
+               item = path_list_lookup(re->pair->one->path, entries);
+               if (!item)
+                       re->src_entry = insert_stage_data(re->pair->one->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->src_entry = item->util;
+
+               item = path_list_lookup(re->pair->two->path, entries);
+               if (!item)
+                       re->dst_entry = insert_stage_data(re->pair->two->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->dst_entry = item->util;
+               item = path_list_insert(pair->one->path, renames);
+               item->util = re;
+       }
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       diff_queued_diff.nr = 0;
+       diff_flush(&opts);
+       return renames;
+}
+
+int update_stages(const char *path, struct diff_filespec *o,
+               struct diff_filespec *a, struct diff_filespec *b, int clear)
+{
+       int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+       if (clear)
+               if (remove_file_from_cache(path))
+                       return -1;
+       if (o)
+               if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
+                       return -1;
+       if (a)
+               if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
+                       return -1;
+       if (b)
+               if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
+                       return -1;
+       return 0;
+}
+
+static int remove_path(const char *name)
+{
+       int ret, len;
+       char *slash, *dirs;
+
+       ret = unlink(name);
+       if (ret)
+               return ret;
+       len = strlen(name);
+       dirs = malloc(len+1);
+       memcpy(dirs, name, len);
+       dirs[len] = '\0';
+       while ((slash = strrchr(name, '/'))) {
+               *slash = '\0';
+               len = slash - name;
+               if (rmdir(name) != 0)
+                       break;
+       }
+       free(dirs);
+       return ret;
+}
+
+int remove_file(int clean, const char *path)
+{
+       int update_cache = index_only || clean;
+       int update_working_directory = !index_only;
+
+       if (update_cache) {
+               if (!cache_dirty)
+                       read_cache_from(current_index_file);
+               cache_dirty++;
+               if (remove_file_from_cache(path))
+                       return -1;
+       }
+       if (update_working_directory)
+       {
+               unlink(path);
+               if (errno != ENOENT || errno != EISDIR)
+                       return -1;
+               remove_path(path);
+       }
+       return 0;
+}
+
+static char *unique_path(const char *path, const char *branch)
+{
+       char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
+       int suffix = 0;
+       struct stat st;
+       char *p = newpath + strlen(path);
+       strcpy(newpath, path);
+       *(p++) = '~';
+       strcpy(p, branch);
+       for (; *p; ++p)
+               if ('/' == *p)
+                       *p = '_';
+       while (path_list_has_path(&current_file_set, newpath) ||
+              path_list_has_path(&current_directory_set, newpath) ||
+              lstat(newpath, &st) == 0)
+               sprintf(p, "_%d", suffix++);
+
+       path_list_insert(newpath, &current_file_set);
+       return newpath;
+}
+
+static int mkdir_p(const char *path, unsigned long mode)
+{
+       /* path points to cache entries, so strdup before messing with it */
+       char *buf = strdup(path);
+       int result = safe_create_leading_directories(buf);
+       free(buf);
+       return result;
+}
+
+static void flush_buffer(int fd, const char *buf, unsigned long size)
+{
+       while (size > 0) {
+               long ret = xwrite(fd, buf, size);
+               if (ret < 0) {
+                       /* Ignore epipe */
+                       if (errno == EPIPE)
+                               break;
+                       die("merge-recursive: %s", strerror(errno));
+               } else if (!ret) {
+                       die("merge-recursive: disk full?");
+               }
+               size -= ret;
+               buf += ret;
+       }
+}
+
+void update_file_flags(const unsigned char *sha,
+                      unsigned mode,
+                      const char *path,
+                      int update_cache,
+                      int update_wd)
+{
+       if (index_only)
+               update_wd = 0;
+
+       if (update_wd) {
+               char type[20];
+               void *buf;
+               unsigned long size;
+
+               buf = read_sha1_file(sha, type, &size);
+               if (!buf)
+                       die("cannot read object %s '%s'", sha1_to_hex(sha), path);
+               if (strcmp(type, blob_type) != 0)
+                       die("blob expected for %s '%s'", sha1_to_hex(sha), path);
+
+               if (S_ISREG(mode)) {
+                       int fd;
+                       if (mkdir_p(path, 0777))
+                               die("failed to create path %s: %s", path, strerror(errno));
+                       unlink(path);
+                       if (mode & 0100)
+                               mode = 0777;
+                       else
+                               mode = 0666;
+                       fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
+                       if (fd < 0)
+                               die("failed to open %s: %s", path, strerror(errno));
+                       flush_buffer(fd, buf, size);
+                       close(fd);
+               } else if (S_ISLNK(mode)) {
+                       char *lnk = malloc(size + 1);
+                       memcpy(lnk, buf, size);
+                       lnk[size] = '\0';
+                       mkdir_p(path, 0777);
+                       unlink(lnk);
+                       symlink(lnk, path);
+               } else
+                       die("do not know what to do with %06o %s '%s'",
+                           mode, sha1_to_hex(sha), path);
+       }
+       if (update_cache)
+               add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
+}
+
+void update_file(int clean,
+               const unsigned char *sha,
+               unsigned mode,
+               const char *path)
+{
+       update_file_flags(sha, mode, path, index_only || clean, !index_only);
+}
+
+/* Low level file merging, update and removal */
+
+struct merge_file_info
+{
+       unsigned char sha[20];
+       unsigned mode;
+       unsigned clean:1,
+                merge:1;
+};
+
+static char *git_unpack_file(const unsigned char *sha1, char *path)
+{
+       void *buf;
+       char type[20];
+       unsigned long size;
+       int fd;
+
+       buf = read_sha1_file(sha1, type, &size);
+       if (!buf || strcmp(type, blob_type))
+               die("unable to read blob object %s", sha1_to_hex(sha1));
+
+       strcpy(path, ".merge_file_XXXXXX");
+       fd = mkstemp(path);
+       if (fd < 0)
+               die("unable to create temp-file");
+       flush_buffer(fd, buf, size);
+       close(fd);
+       return path;
+}
+
+static struct merge_file_info merge_file(struct diff_filespec *o,
+               struct diff_filespec *a, struct diff_filespec *b,
+               const char *branch1, const char *branch2)
+{
+       struct merge_file_info result;
+       result.merge = 0;
+       result.clean = 1;
+
+       if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
+               result.clean = 0;
+               if (S_ISREG(a->mode)) {
+                       result.mode = a->mode;
+                       memcpy(result.sha, a->sha1, 20);
+               } else {
+                       result.mode = b->mode;
+                       memcpy(result.sha, b->sha1, 20);
+               }
+       } else {
+               if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
+                       result.merge = 1;
+
+               result.mode = a->mode == o->mode ? b->mode: a->mode;
+
+               if (sha_eq(a->sha1, o->sha1))
+                       memcpy(result.sha, b->sha1, 20);
+               else if (sha_eq(b->sha1, o->sha1))
+                       memcpy(result.sha, a->sha1, 20);
+               else if (S_ISREG(a->mode)) {
+                       int code = 1, fd;
+                       struct stat st;
+                       char orig[PATH_MAX];
+                       char src1[PATH_MAX];
+                       char src2[PATH_MAX];
+                       const char *argv[] = {
+                               "merge", "-L", NULL, "-L", NULL, "-L", NULL,
+                               NULL, NULL, NULL,
+                               NULL
+                       };
+                       char *la, *lb, *lo;
+
+                       git_unpack_file(o->sha1, orig);
+                       git_unpack_file(a->sha1, src1);
+                       git_unpack_file(b->sha1, src2);
+
+                       argv[2] = la = strdup(mkpath("%s/%s", branch1, a->path));
+                       argv[6] = lb = strdup(mkpath("%s/%s", branch2, b->path));
+                       argv[4] = lo = strdup(mkpath("orig/%s", o->path));
+                       argv[7] = src1;
+                       argv[8] = orig;
+                       argv[9] = src2,
+
+                       code = run_command_v(10, argv);
+
+                       free(la);
+                       free(lb);
+                       free(lo);
+                       if (code && code < -256) {
+                               die("Failed to execute 'merge'. merge(1) is used as the "
+                                   "file-level merge tool. Is 'merge' in your path?");
+                       }
+                       fd = open(src1, O_RDONLY);
+                       if (fd < 0 || fstat(fd, &st) < 0 ||
+                                       index_fd(result.sha, fd, &st, 1,
+                                               "blob"))
+                               die("Unable to add %s to database", src1);
+
+                       unlink(orig);
+                       unlink(src1);
+                       unlink(src2);
+
+                       result.clean = WEXITSTATUS(code) == 0;
+               } else {
+                       if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
+                               die("cannot merge modes?");
+
+                       memcpy(result.sha, a->sha1, 20);
+
+                       if (!sha_eq(a->sha1, b->sha1))
+                               result.clean = 0;
+               }
+       }
+
+       return result;
+}
+
+static void conflict_rename_rename(struct rename *ren1,
+                                  const char *branch1,
+                                  struct rename *ren2,
+                                  const char *branch2)
+{
+       char *del[2];
+       int delp = 0;
+       const char *ren1_dst = ren1->pair->two->path;
+       const char *ren2_dst = ren2->pair->two->path;
+       const char *dst_name1 = ren1_dst;
+       const char *dst_name2 = ren2_dst;
+       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+               dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
+               output("%s is a directory in %s adding as %s instead",
+                      ren1_dst, branch2, dst_name1);
+               remove_file(0, ren1_dst);
+       }
+       if (path_list_has_path(&current_directory_set, ren2_dst)) {
+               dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
+               output("%s is a directory in %s adding as %s instead",
+                      ren2_dst, branch1, dst_name2);
+               remove_file(0, ren2_dst);
+       }
+       update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
+       update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+       while (delp--)
+               free(del[delp]);
+}
+
+static void conflict_rename_dir(struct rename *ren1,
+                               const char *branch1)
+{
+       char *new_path = unique_path(ren1->pair->two->path, branch1);
+       output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
+       remove_file(0, ren1->pair->two->path);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
+       free(new_path);
+}
+
+static void conflict_rename_rename_2(struct rename *ren1,
+                                    const char *branch1,
+                                    struct rename *ren2,
+                                    const char *branch2)
+{
+       char *new_path1 = unique_path(ren1->pair->two->path, branch1);
+       char *new_path2 = unique_path(ren2->pair->two->path, branch2);
+       output("Renaming %s to %s and %s to %s instead",
+              ren1->pair->one->path, new_path1,
+              ren2->pair->one->path, new_path2);
+       remove_file(0, ren1->pair->two->path);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
+       update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
+       free(new_path2);
+       free(new_path1);
+}
+
+static int process_renames(struct path_list *a_renames,
+                          struct path_list *b_renames,
+                          const char *a_branch,
+                          const char *b_branch)
+{
+       int clean_merge = 1, i, j;
+       struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
+       const struct rename *sre;
+
+       for (i = 0; i < a_renames->nr; i++) {
+               sre = a_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &a_by_dst)->util
+                       = sre->dst_entry;
+       }
+       for (i = 0; i < b_renames->nr; i++) {
+               sre = b_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &b_by_dst)->util
+                       = sre->dst_entry;
+       }
+
+       for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
+               int compare;
+               char *src;
+               struct path_list *renames1, *renames2, *renames2Dst;
+               struct rename *ren1 = NULL, *ren2 = NULL;
+               const char *branch1, *branch2;
+               const char *ren1_src, *ren1_dst;
+
+               if (i >= a_renames->nr) {
+                       compare = 1;
+                       ren2 = b_renames->items[j++].util;
+               } else if (j >= b_renames->nr) {
+                       compare = -1;
+                       ren1 = a_renames->items[i++].util;
+               } else {
+                       compare = strcmp(a_renames->items[i].path,
+                                       b_renames->items[j].path);
+                       if (compare <= 0)
+                               ren1 = a_renames->items[i++].util;
+                       if (compare >= 0)
+                               ren2 = b_renames->items[j++].util;
+               }
+
+               /* TODO: refactor, so that 1/2 are not needed */
+               if (ren1) {
+                       renames1 = a_renames;
+                       renames2 = b_renames;
+                       renames2Dst = &b_by_dst;
+                       branch1 = a_branch;
+                       branch2 = b_branch;
+               } else {
+                       struct rename *tmp;
+                       renames1 = b_renames;
+                       renames2 = a_renames;
+                       renames2Dst = &a_by_dst;
+                       branch1 = b_branch;
+                       branch2 = a_branch;
+                       tmp = ren2;
+                       ren2 = ren1;
+                       ren1 = tmp;
+               }
+               src = ren1->pair->one->path;
+
+               ren1->dst_entry->processed = 1;
+               ren1->src_entry->processed = 1;
+
+               if (ren1->processed)
+                       continue;
+               ren1->processed = 1;
+
+               ren1_src = ren1->pair->one->path;
+               ren1_dst = ren1->pair->two->path;
+
+               if (ren2) {
+                       const char *ren2_src = ren2->pair->one->path;
+                       const char *ren2_dst = ren2->pair->two->path;
+                       /* Renamed in 1 and renamed in 2 */
+                       if (strcmp(ren1_src, ren2_src) != 0)
+                               die("ren1.src != ren2.src");
+                       ren2->dst_entry->processed = 1;
+                       ren2->processed = 1;
+                       if (strcmp(ren1_dst, ren2_dst) != 0) {
+                               clean_merge = 0;
+                               output("CONFLICT (rename/rename): "
+                                      "Rename %s->%s in branch %s "
+                                      "rename %s->%s in %s",
+                                      src, ren1_dst, branch1,
+                                      src, ren2_dst, branch2);
+                               conflict_rename_rename(ren1, branch1, ren2, branch2);
+                       } else {
+                               struct merge_file_info mfi;
+                               remove_file(1, ren1_src);
+                               mfi = merge_file(ren1->pair->one,
+                                                ren1->pair->two,
+                                                ren2->pair->two,
+                                                branch1,
+                                                branch2);
+                               if (mfi.merge || !mfi.clean)
+                                       output("Renaming %s->%s", src, ren1_dst);
+
+                               if (mfi.merge)
+                                       output("Auto-merging %s", ren1_dst);
+
+                               if (!mfi.clean) {
+                                       output("CONFLICT (content): merge conflict in %s",
+                                              ren1_dst);
+                                       clean_merge = 0;
+
+                                       if (!index_only)
+                                               update_stages(ren1_dst,
+                                                             ren1->pair->one,
+                                                             ren1->pair->two,
+                                                             ren2->pair->two,
+                                                             1 /* clear */);
+                               }
+                               update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                       }
+               } else {
+                       /* Renamed in 1, maybe changed in 2 */
+                       struct path_list_item *item;
+                       /* we only use sha1 and mode of these */
+                       struct diff_filespec src_other, dst_other;
+                       int try_merge, stage = a_renames == renames1 ? 3: 2;
+
+                       remove_file(1, ren1_src);
+
+                       memcpy(src_other.sha1,
+                                       ren1->src_entry->stages[stage].sha, 20);
+                       src_other.mode = ren1->src_entry->stages[stage].mode;
+                       memcpy(dst_other.sha1,
+                                       ren1->dst_entry->stages[stage].sha, 20);
+                       dst_other.mode = ren1->dst_entry->stages[stage].mode;
+
+                       try_merge = 0;
+
+                       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+                               clean_merge = 0;
+                               output("CONFLICT (rename/directory): Rename %s->%s in %s "
+                                      " directory %s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               conflict_rename_dir(ren1, branch1);
+                       } else if (sha_eq(src_other.sha1, null_sha1)) {
+                               clean_merge = 0;
+                               output("CONFLICT (rename/delete): Rename %s->%s in %s "
+                                      "and deleted in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      branch2);
+                               update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
+                       } else if (!sha_eq(dst_other.sha1, null_sha1)) {
+                               const char *new_path;
+                               clean_merge = 0;
+                               try_merge = 1;
+                               output("CONFLICT (rename/add): Rename %s->%s in %s. "
+                                      "%s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               new_path = unique_path(ren1_dst, branch2);
+                               output("Adding as %s instead", new_path);
+                               update_file(0, dst_other.sha1, dst_other.mode, new_path);
+                       } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
+                               ren2 = item->util;
+                               clean_merge = 0;
+                               ren2->processed = 1;
+                               output("CONFLICT (rename/rename): Rename %s->%s in %s. "
+                                      "Rename %s->%s in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren2->pair->one->path, ren2->pair->two->path, branch2);
+                               conflict_rename_rename_2(ren1, branch1, ren2, branch2);
+                       } else
+                               try_merge = 1;
+
+                       if (try_merge) {
+                               struct diff_filespec *o, *a, *b;
+                               struct merge_file_info mfi;
+                               src_other.path = (char *)ren1_src;
+
+                               o = ren1->pair->one;
+                               if (a_renames == renames1) {
+                                       a = ren1->pair->two;
+                                       b = &src_other;
+                               } else {
+                                       b = ren1->pair->two;
+                                       a = &src_other;
+                               }
+                               mfi = merge_file(o, a, b,
+                                               a_branch, b_branch);
+
+                               if (mfi.merge || !mfi.clean)
+                                       output("Renaming %s => %s", ren1_src, ren1_dst);
+                               if (mfi.merge)
+                                       output("Auto-merging %s", ren1_dst);
+                               if (!mfi.clean) {
+                                       output("CONFLICT (rename/modify): Merge conflict in %s",
+                                              ren1_dst);
+                                       clean_merge = 0;
+
+                                       if (!index_only)
+                                               update_stages(ren1_dst,
+                                                               o, a, b, 1);
+                               }
+                               update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                       }
+               }
+       }
+       path_list_clear(&a_by_dst, 0);
+       path_list_clear(&b_by_dst, 0);
+
+       if (cache_dirty)
+               flush_cache();
+       return clean_merge;
+}
+
+static unsigned char *has_sha(const unsigned char *sha)
+{
+       return memcmp(sha, null_sha1, 20) == 0 ? NULL: (unsigned char *)sha;
+}
+
+/* Per entry merge function */
+static int process_entry(const char *path, struct stage_data *entry,
+                        const char *branch1,
+                        const char *branch2)
+{
+       /*
+       printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
+       print_index_entry("\tpath: ", entry);
+       */
+       int clean_merge = 1;
+       unsigned char *o_sha = has_sha(entry->stages[1].sha);
+       unsigned char *a_sha = has_sha(entry->stages[2].sha);
+       unsigned char *b_sha = has_sha(entry->stages[3].sha);
+       unsigned o_mode = entry->stages[1].mode;
+       unsigned a_mode = entry->stages[2].mode;
+       unsigned b_mode = entry->stages[3].mode;
+
+       if (o_sha && (!a_sha || !b_sha)) {
+               /* Case A: Deleted in one */
+               if ((!a_sha && !b_sha) ||
+                   (sha_eq(a_sha, o_sha) && !b_sha) ||
+                   (!a_sha && sha_eq(b_sha, o_sha))) {
+                       /* Deleted in both or deleted in one and
+                        * unchanged in the other */
+                       if (a_sha)
+                               output("Removing %s", path);
+                       remove_file(1, path);
+               } else {
+                       /* Deleted in one and changed in the other */
+                       clean_merge = 0;
+                       if (!a_sha) {
+                               output("CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch1,
+                                      branch2, branch2, path);
+                               update_file(0, b_sha, b_mode, path);
+                       } else {
+                               output("CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch2,
+                                      branch1, branch1, path);
+                               update_file(0, a_sha, a_mode, path);
+                       }
+               }
+
+       } else if ((!o_sha && a_sha && !b_sha) ||
+                  (!o_sha && !a_sha && b_sha)) {
+               /* Case B: Added in one. */
+               const char *add_branch;
+               const char *other_branch;
+               unsigned mode;
+               const unsigned char *sha;
+               const char *conf;
+
+               if (a_sha) {
+                       add_branch = branch1;
+                       other_branch = branch2;
+                       mode = a_mode;
+                       sha = a_sha;
+                       conf = "file/directory";
+               } else {
+                       add_branch = branch2;
+                       other_branch = branch1;
+                       mode = b_mode;
+                       sha = b_sha;
+                       conf = "directory/file";
+               }
+               if (path_list_has_path(&current_directory_set, path)) {
+                       const char *new_path = unique_path(path, add_branch);
+                       clean_merge = 0;
+                       output("CONFLICT (%s): There is a directory with name %s in %s. "
+                              "Adding %s as %s",
+                              conf, path, other_branch, path, new_path);
+                       remove_file(0, path);
+                       update_file(0, sha, mode, new_path);
+               } else {
+                       output("Adding %s", path);
+                       update_file(1, sha, mode, path);
+               }
+       } else if (!o_sha && a_sha && b_sha) {
+               /* Case C: Added in both (check for same permissions). */
+               if (sha_eq(a_sha, b_sha)) {
+                       if (a_mode != b_mode) {
+                               clean_merge = 0;
+                               output("CONFLICT: File %s added identically in both branches, "
+                                      "but permissions conflict %06o->%06o",
+                                      path, a_mode, b_mode);
+                               output("CONFLICT: adding with permission: %06o", a_mode);
+                               update_file(0, a_sha, a_mode, path);
+                       } else {
+                               /* This case is handled by git-read-tree */
+                               assert(0 && "This case must be handled by git-read-tree");
+                       }
+               } else {
+                       const char *new_path1, *new_path2;
+                       clean_merge = 0;
+                       new_path1 = unique_path(path, branch1);
+                       new_path2 = unique_path(path, branch2);
+                       output("CONFLICT (add/add): File %s added non-identically "
+                              "in both branches. Adding as %s and %s instead.",
+                              path, new_path1, new_path2);
+                       remove_file(0, path);
+                       update_file(0, a_sha, a_mode, new_path1);
+                       update_file(0, b_sha, b_mode, new_path2);
+               }
+
+       } else if (o_sha && a_sha && b_sha) {
+               /* case D: Modified in both, but differently. */
+               struct merge_file_info mfi;
+               struct diff_filespec o, a, b;
+
+               output("Auto-merging %s", path);
+               o.path = a.path = b.path = (char *)path;
+               memcpy(o.sha1, o_sha, 20);
+               o.mode = o_mode;
+               memcpy(a.sha1, a_sha, 20);
+               a.mode = a_mode;
+               memcpy(b.sha1, b_sha, 20);
+               b.mode = b_mode;
+
+               mfi = merge_file(&o, &a, &b,
+                                branch1, branch2);
+
+               if (mfi.clean)
+                       update_file(1, mfi.sha, mfi.mode, path);
+               else {
+                       clean_merge = 0;
+                       output("CONFLICT (content): Merge conflict in %s", path);
+
+                       if (index_only)
+                               update_file(0, mfi.sha, mfi.mode, path);
+                       else
+                               update_file_flags(mfi.sha, mfi.mode, path,
+                                             0 /* update_cache */, 1 /* update_working_directory */);
+               }
+       } else
+               die("Fatal merge failure, shouldn't happen.");
+
+       if (cache_dirty)
+               flush_cache();
+
+       return clean_merge;
+}
+
+static int merge_trees(struct tree *head,
+                      struct tree *merge,
+                      struct tree *common,
+                      const char *branch1,
+                      const char *branch2,
+                      struct tree **result)
+{
+       int code, clean;
+       if (sha_eq(common->object.sha1, merge->object.sha1)) {
+               output("Already uptodate!");
+               *result = head;
+               return 1;
+       }
+
+       code = git_merge_trees(index_only, common, head, merge);
+
+       if (code != 0)
+               die("merging of trees %s and %s failed",
+                   sha1_to_hex(head->object.sha1),
+                   sha1_to_hex(merge->object.sha1));
+
+       *result = git_write_tree();
+
+       if (!*result) {
+               struct path_list *entries, *re_head, *re_merge;
+               int i;
+               path_list_clear(&current_file_set, 1);
+               path_list_clear(&current_directory_set, 1);
+               get_files_dirs(head);
+               get_files_dirs(merge);
+
+               entries = get_unmerged();
+               re_head  = get_renames(head, common, head, merge, entries);
+               re_merge = get_renames(merge, common, head, merge, entries);
+               clean = process_renames(re_head, re_merge,
+                               branch1, branch2);
+               for (i = 0; i < entries->nr; i++) {
+                       const char *path = entries->items[i].path;
+                       struct stage_data *e = entries->items[i].util;
+                       if (e->processed)
+                               continue;
+                       if (!process_entry(path, e, branch1, branch2))
+                               clean = 0;
+               }
+
+               path_list_clear(re_merge, 0);
+               path_list_clear(re_head, 0);
+               path_list_clear(entries, 1);
+
+               if (clean || index_only)
+                       *result = git_write_tree();
+               else
+                       *result = NULL;
+       } else {
+               clean = 1;
+               printf("merging of trees %s and %s resulted in %s\n",
+                      sha1_to_hex(head->object.sha1),
+                      sha1_to_hex(merge->object.sha1),
+                      sha1_to_hex((*result)->object.sha1));
+       }
+
+       return clean;
+}
+
+static struct commit_list *reverse_commit_list(struct commit_list *list)
+{
+       struct commit_list *next = NULL, *current, *backup;
+       for (current = list; current; current = backup) {
+               backup = current->next;
+               current->next = next;
+               next = current;
+       }
+       return next;
+}
+
+/*
+ * Merge the commits h1 and h2, return the resulting virtual
+ * commit object and a flag indicating the cleaness of the merge.
+ */
+static
+int merge(struct commit *h1,
+                         struct commit *h2,
+                         const char *branch1,
+                         const char *branch2,
+                         int call_depth /* =0 */,
+                         struct commit *ancestor /* =None */,
+                         struct commit **result)
+{
+       struct commit_list *ca = NULL, *iter;
+       struct commit *merged_common_ancestors;
+       struct tree *mrtree;
+       int clean;
+
+       output("Merging:");
+       output_commit_title(h1);
+       output_commit_title(h2);
+
+       if (ancestor)
+               commit_list_insert(ancestor, &ca);
+       else
+               ca = reverse_commit_list(get_merge_bases(h1, h2, 1));
+
+       output("found %u common ancestor(s):", commit_list_count(ca));
+       for (iter = ca; iter; iter = iter->next)
+               output_commit_title(iter->item);
+
+       merged_common_ancestors = pop_commit(&ca);
+       if (merged_common_ancestors == NULL) {
+               /* if there is no common ancestor, make an empty tree */
+               struct tree *tree = xcalloc(1, sizeof(struct tree));
+               unsigned char hdr[40];
+               int hdrlen;
+
+               tree->object.parsed = 1;
+               tree->object.type = OBJ_TREE;
+               write_sha1_file_prepare(NULL, 0, tree_type, tree->object.sha1,
+                                       hdr, &hdrlen);
+               merged_common_ancestors = make_virtual_commit(tree, "ancestor");
+       }
+
+       for (iter = ca; iter; iter = iter->next) {
+               output_indent = call_depth + 1;
+               /*
+                * When the merge fails, the result contains files
+                * with conflict markers. The cleanness flag is
+                * ignored, it was never acutally used, as result of
+                * merge_trees has always overwritten it: the commited
+                * "conflicts" were already resolved.
+                */
+               merge(merged_common_ancestors, iter->item,
+                     "Temporary merge branch 1",
+                     "Temporary merge branch 2",
+                     call_depth + 1,
+                     NULL,
+                     &merged_common_ancestors);
+               output_indent = call_depth;
+
+               if (!merged_common_ancestors)
+                       die("merge returned no commit");
+       }
+
+       if (call_depth == 0) {
+               setup_index(0 /* $GIT_DIR/index */);
+               index_only = 0;
+       } else {
+               setup_index(1 /* temporary index */);
+               git_read_tree(h1->tree);
+               index_only = 1;
+       }
+
+       clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
+                           branch1, branch2, &mrtree);
+
+       if (!ancestor && (clean || index_only)) {
+               *result = make_virtual_commit(mrtree, "merged tree");
+               commit_list_insert(h1, &(*result)->parents);
+               commit_list_insert(h2, &(*result)->parents->next);
+       } else
+               *result = NULL;
+
+       return clean;
+}
+
+static struct commit *get_ref(const char *ref)
+{
+       unsigned char sha1[20];
+       struct object *object;
+
+       if (get_sha1(ref, sha1))
+               die("Could not resolve ref '%s'", ref);
+       object = deref_tag(parse_object(sha1), ref, strlen(ref));
+       if (object->type != OBJ_COMMIT)
+               return NULL;
+       if (parse_commit((struct commit *)object))
+               die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
+       return (struct commit *)object;
+}
+
+int main(int argc, char *argv[])
+{
+       static const char *bases[2];
+       static unsigned bases_count = 0;
+       int i, clean;
+       const char *branch1, *branch2;
+       struct commit *result, *h1, *h2;
+
+       original_index_file = getenv("GIT_INDEX_FILE");
+
+       if (!original_index_file)
+               original_index_file = strdup(git_path("index"));
+
+       temporary_index_file = strdup(git_path("mrg-rcrsv-tmp-idx"));
+
+       if (argc < 4)
+               die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
+
+       for (i = 1; i < argc; ++i) {
+               if (!strcmp(argv[i], "--"))
+                       break;
+               if (bases_count < sizeof(bases)/sizeof(*bases))
+                       bases[bases_count++] = argv[i];
+       }
+       if (argc - i != 3) /* "--" "<head>" "<remote>" */
+               die("Not handling anything other than two heads merge.");
+
+       branch1 = argv[++i];
+       branch2 = argv[++i];
+       printf("Merging %s with %s\n", branch1, branch2);
+
+       h1 = get_ref(branch1);
+       h2 = get_ref(branch2);
+
+       if (bases_count == 1) {
+               struct commit *ancestor = get_ref(bases[0]);
+               clean = merge(h1, h2, branch1, branch2, 0, ancestor, &result);
+       } else
+               clean = merge(h1, h2, branch1, branch2, 0, NULL, &result);
+
+       if (cache_dirty)
+               flush_cache();
+
+       return clean ? 0: 1;
+}
+
+/*
+vim: sw=8 noet
+*/
index b6982ea..20c9d49 100644 (file)
@@ -842,6 +842,23 @@ unmap:
        die("index file corrupt");
 }
 
+int discard_cache()
+{
+       int ret;
+
+       active_nr = active_cache_changed = 0;
+       index_file_timestamp = 0;
+       cache_tree_free(&active_cache_tree);
+       if (cache_mmap == NULL)
+               return 0;
+       ret = munmap(cache_mmap, cache_mmap_size);
+       cache_mmap = NULL;
+       cache_mmap_size = 0;
+
+       /* no need to throw away allocated active_cache */
+       return ret;
+}
+
 #define WRITE_BUFFER_SIZE 8192
 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
 static unsigned long write_buffer_len;