[PATCH] Avoid wasting memory in git-rev-list
[git/git.git] / commit.c
index eda45d7..f735f98 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -1,24 +1,86 @@
+#include <ctype.h>
+#include "tag.h"
 #include "commit.h"
 #include "cache.h"
-#include <string.h>
+
+int save_commit_buffer = 1;
+
+struct sort_node
+{
+       /*
+         * the number of children of the associated commit
+         * that also occur in the list being sorted.
+         */
+       unsigned int indegree;
+
+       /*
+         * reference to original list item that we will re-use
+         * on output.
+         */
+       struct commit_list * list_item;
+
+};
 
 const char *commit_type = "commit";
 
-struct commit *lookup_commit(unsigned char *sha1)
+enum cmit_fmt get_commit_format(const char *arg)
+{
+       if (!*arg)
+               return CMIT_FMT_DEFAULT;
+       if (!strcmp(arg, "=raw"))
+               return CMIT_FMT_RAW;
+       if (!strcmp(arg, "=medium"))
+               return CMIT_FMT_MEDIUM;
+       if (!strcmp(arg, "=short"))
+               return CMIT_FMT_SHORT;
+       if (!strcmp(arg, "=full"))
+               return CMIT_FMT_FULL;
+       if (!strcmp(arg, "=oneline"))
+               return CMIT_FMT_ONELINE;
+       die("invalid --pretty format");
+}
+
+static struct commit *check_commit(struct object *obj,
+                                  const unsigned char *sha1,
+                                  int quiet)
+{
+       if (obj->type != commit_type) {
+               if (!quiet)
+                       error("Object %s is a %s, not a commit",
+                             sha1_to_hex(sha1), obj->type);
+               return NULL;
+       }
+       return (struct commit *) obj;
+}
+
+struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
+                                             int quiet)
+{
+       struct object *obj = deref_tag(parse_object(sha1));
+
+       if (!obj)
+               return NULL;
+       return check_commit(obj, sha1, quiet);
+}
+
+struct commit *lookup_commit_reference(const unsigned char *sha1)
+{
+       return lookup_commit_reference_gently(sha1, 0);
+}
+
+struct commit *lookup_commit(const unsigned char *sha1)
 {
        struct object *obj = lookup_object(sha1);
        if (!obj) {
-               struct commit *ret = malloc(sizeof(struct commit));
+               struct commit *ret = xmalloc(sizeof(struct commit));
                memset(ret, 0, sizeof(struct commit));
                created_object(sha1, &ret->object);
+               ret->object.type = commit_type;
                return ret;
        }
-       if (obj->parsed && obj->type != commit_type) {
-               error("Object %s is a %s, not a commit", 
-                     sha1_to_hex(sha1), obj->type);
-               return NULL;
-       }
-       return (struct commit *) obj;
+       if (!obj->type)
+               obj->type = commit_type;
+       return check_commit(obj, sha1, 0);
 }
 
 static unsigned long parse_commit_date(const char *buf)
@@ -39,40 +101,186 @@ static unsigned long parse_commit_date(const char *buf)
        return date;
 }
 
+static struct commit_graft {
+       unsigned char sha1[20];
+       int nr_parent;
+       unsigned char parent[0][20]; /* more */
+} **commit_graft;
+static int commit_graft_alloc, commit_graft_nr;
+
+static int commit_graft_pos(const unsigned char *sha1)
+{
+       int lo, hi;
+       lo = 0;
+       hi = commit_graft_nr;
+       while (lo < hi) {
+               int mi = (lo + hi) / 2;
+               struct commit_graft *graft = commit_graft[mi];
+               int cmp = memcmp(sha1, graft->sha1, 20);
+               if (!cmp)
+                       return mi;
+               if (cmp < 0)
+                       hi = mi;
+               else
+                       lo = mi + 1;
+       }
+       return -lo - 1;
+}
+
+static void prepare_commit_graft(void)
+{
+       char *graft_file = get_graft_file();
+       FILE *fp = fopen(graft_file, "r");
+       char buf[1024];
+       if (!fp) {
+               commit_graft = (struct commit_graft **) "hack";
+               return;
+       }
+       while (fgets(buf, sizeof(buf), fp)) {
+               /* The format is just "Commit Parent1 Parent2 ...\n" */
+               int len = strlen(buf);
+               int i;
+               struct commit_graft *graft = NULL;
+
+               if (buf[len-1] == '\n')
+                       buf[--len] = 0;
+               if (buf[0] == '#')
+                       continue;
+               if ((len + 1) % 41) {
+               bad_graft_data:
+                       error("bad graft data: %s", buf);
+                       free(graft);
+                       continue;
+               }
+               i = (len + 1) / 41 - 1;
+               graft = xmalloc(sizeof(*graft) + 20 * i);
+               graft->nr_parent = i;
+               if (get_sha1_hex(buf, graft->sha1))
+                       goto bad_graft_data;
+               for (i = 40; i < len; i += 41) {
+                       if (buf[i] != ' ')
+                               goto bad_graft_data;
+                       if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
+                               goto bad_graft_data;
+               }
+               i = commit_graft_pos(graft->sha1);
+               if (0 <= i) {
+                       error("duplicate graft data: %s", buf);
+                       free(graft);
+                       continue;
+               }
+               i = -i - 1;
+               if (commit_graft_alloc <= ++commit_graft_nr) {
+                       commit_graft_alloc = alloc_nr(commit_graft_alloc);
+                       commit_graft = xrealloc(commit_graft,
+                                               sizeof(*commit_graft) *
+                                               commit_graft_alloc);
+               }
+               if (i < commit_graft_nr)
+                       memmove(commit_graft + i + 1,
+                               commit_graft + i,
+                               (commit_graft_nr - i - 1) *
+                               sizeof(*commit_graft));
+               commit_graft[i] = graft;
+       }
+       fclose(fp);
+}
+
+static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
+{
+       int pos;
+       if (!commit_graft)
+               prepare_commit_graft();
+       pos = commit_graft_pos(sha1);
+       if (pos < 0)
+               return NULL;
+       return commit_graft[pos];
+}
+
+int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
+{
+       char *bufptr = buffer;
+       unsigned char parent[20];
+       struct commit_list **pptr;
+       struct commit_graft *graft;
+
+       if (item->object.parsed)
+               return 0;
+       item->object.parsed = 1;
+       if (memcmp(bufptr, "tree ", 5))
+               return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
+       if (get_sha1_hex(bufptr + 5, parent) < 0)
+               return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
+       item->tree = lookup_tree(parent);
+       if (item->tree)
+               add_ref(&item->object, &item->tree->object);
+       bufptr += 46; /* "tree " + "hex sha1" + "\n" */
+       pptr = &item->parents;
+
+       graft = lookup_commit_graft(item->object.sha1);
+       while (!memcmp(bufptr, "parent ", 7)) {
+               struct commit *new_parent;
+
+               if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
+                       return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
+               bufptr += 48;
+               if (graft)
+                       continue;
+               new_parent = lookup_commit(parent);
+               if (new_parent) {
+                       pptr = &commit_list_insert(new_parent, pptr)->next;
+                       add_ref(&item->object, &new_parent->object);
+               }
+       }
+       if (graft) {
+               int i;
+               struct commit *new_parent;
+               for (i = 0; i < graft->nr_parent; i++) {
+                       new_parent = lookup_commit(graft->parent[i]);
+                       if (!new_parent)
+                               continue;
+                       pptr = &commit_list_insert(new_parent, pptr)->next;
+                       add_ref(&item->object, &new_parent->object);
+               }
+       }
+       item->date = parse_commit_date(bufptr);
+       return 0;
+}
+
 int parse_commit(struct commit *item)
 {
        char type[20];
-       void * buffer, *bufptr;
+       void *buffer;
        unsigned long size;
-       unsigned char parent[20];
+       int ret;
+
        if (item->object.parsed)
                return 0;
-       item->object.parsed = 1;
-       buffer = bufptr = read_sha1_file(item->object.sha1, type, &size);
+       buffer = read_sha1_file(item->object.sha1, type, &size);
        if (!buffer)
                return error("Could not read %s",
                             sha1_to_hex(item->object.sha1));
-       if (strcmp(type, commit_type))
+       if (strcmp(type, commit_type)) {
+               free(buffer);
                return error("Object %s not a commit",
                             sha1_to_hex(item->object.sha1));
-       item->object.type = commit_type;
-       get_sha1_hex(bufptr + 5, parent);
-       item->tree = lookup_tree(parent);
-       add_ref(&item->object, &item->tree->object);
-       bufptr += 46; /* "tree " + "hex sha1" + "\n" */
-       while (!memcmp(bufptr, "parent ", 7) &&
-              !get_sha1_hex(bufptr + 7, parent)) {
-               struct commit_list *new_parent = 
-                       malloc(sizeof(struct commit_list));
-               new_parent->next = item->parents;
-               new_parent->item = lookup_commit(parent);
-               add_ref(&item->object, &new_parent->item->object);
-               item->parents = new_parent;
-               bufptr += 48;
        }
-       item->date = parse_commit_date(bufptr);
+       ret = parse_commit_buffer(item, buffer, size);
+       if (save_commit_buffer && !ret) {
+               item->buffer = buffer;
+               return 0;
+       }
        free(buffer);
-       return 0;
+       return ret;
+}
+
+struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
+{
+       struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
+       new_list->item = item;
+       new_list->next = *list_p;
+       *list_p = new_list;
+       return new_list;
 }
 
 void free_commit_list(struct commit_list *list)
@@ -83,3 +291,311 @@ void free_commit_list(struct commit_list *list)
                free(temp);
        }
 }
+
+struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
+{
+       struct commit_list **pp = list;
+       struct commit_list *p;
+       while ((p = *pp) != NULL) {
+               if (p->item->date < item->date) {
+                       break;
+               }
+               pp = &p->next;
+       }
+       return commit_list_insert(item, pp);
+}
+
+       
+void sort_by_date(struct commit_list **list)
+{
+       struct commit_list *ret = NULL;
+       while (*list) {
+               insert_by_date((*list)->item, &ret);
+               *list = (*list)->next;
+       }
+       *list = ret;
+}
+
+struct commit *pop_most_recent_commit(struct commit_list **list,
+                                     unsigned int mark)
+{
+       struct commit *ret = (*list)->item;
+       struct commit_list *parents = ret->parents;
+       struct commit_list *old = *list;
+
+       *list = (*list)->next;
+       free(old);
+
+       while (parents) {
+               struct commit *commit = parents->item;
+               parse_commit(commit);
+               if (!(commit->object.flags & mark)) {
+                       commit->object.flags |= mark;
+                       insert_by_date(commit, list);
+               }
+               parents = parents->next;
+       }
+       return ret;
+}
+
+/*
+ * Generic support for pretty-printing the header
+ */
+static int get_one_line(const char *msg, unsigned long len)
+{
+       int ret = 0;
+
+       while (len--) {
+               char c = *msg++;
+               ret++;
+               if (c == '\n')
+                       break;
+               if (!c)
+                       return 0;
+       }
+       return ret;
+}
+
+static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
+{
+       char *date;
+       int namelen;
+       unsigned long time;
+       int tz, ret;
+
+       if (fmt == CMIT_FMT_ONELINE)
+               return 0;
+       date = strchr(line, '>');
+       if (!date)
+               return 0;
+       namelen = ++date - line;
+       time = strtoul(date, &date, 10);
+       tz = strtol(date, NULL, 10);
+
+       ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
+       if (fmt == CMIT_FMT_MEDIUM)
+               ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
+       return ret;
+}
+
+static int is_empty_line(const char *line, int len)
+{
+       while (len && isspace(line[len-1]))
+               len--;
+       return !len;
+}
+
+static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
+{
+       int offset = 0;
+
+       if (fmt == CMIT_FMT_ONELINE)
+               return offset;
+       switch (parents) {
+       case 1:
+               break;
+       case 2:
+               /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
+               offset = sprintf(buf, "Merge: %.40s\n", line-41);
+               /* Fallthrough */
+       default:
+               /* Replace the previous '\n' with a space */
+               buf[offset-1] = ' ';
+               offset += sprintf(buf + offset, "%.40s\n", line+7);
+       }
+       return offset;
+}
+
+unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
+{
+       int hdr = 1, body = 0;
+       unsigned long offset = 0;
+       int parents = 0;
+       int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
+
+       for (;;) {
+               const char *line = msg;
+               int linelen = get_one_line(msg, len);
+
+               if (!linelen)
+                       break;
+
+               /*
+                * We want some slop for indentation and a possible
+                * final "...". Thus the "+ 20".
+                */
+               if (offset + linelen + 20 > space) {
+                       memcpy(buf + offset, "    ...\n", 8);
+                       offset += 8;
+                       break;
+               }
+
+               msg += linelen;
+               len -= linelen;
+               if (hdr) {
+                       if (linelen == 1) {
+                               hdr = 0;
+                               if (fmt != CMIT_FMT_ONELINE)
+                                       buf[offset++] = '\n';
+                               continue;
+                       }
+                       if (fmt == CMIT_FMT_RAW) {
+                               memcpy(buf + offset, line, linelen);
+                               offset += linelen;
+                               continue;
+                       }
+                       if (!memcmp(line, "parent ", 7)) {
+                               if (linelen != 48)
+                                       die("bad parent line in commit");
+                               offset += add_parent_info(fmt, buf + offset, line, ++parents);
+                       }
+                       if (!memcmp(line, "author ", 7))
+                               offset += add_user_info("Author", fmt, buf + offset, line + 7);
+                       if (fmt == CMIT_FMT_FULL) {
+                               if (!memcmp(line, "committer ", 10))
+                                       offset += add_user_info("Commit", fmt, buf + offset, line + 10);
+                       }
+                       continue;
+               }
+
+               if (is_empty_line(line, linelen)) {
+                       if (!body)
+                               continue;
+                       if (fmt == CMIT_FMT_SHORT)
+                               break;
+               } else {
+                       body = 1;
+               }
+
+               memset(buf + offset, ' ', indent);
+               memcpy(buf + offset + indent, line, linelen);
+               offset += linelen + indent;
+               if (fmt == CMIT_FMT_ONELINE)
+                       break;
+       }
+       if (fmt == CMIT_FMT_ONELINE) {
+               /* We do not want the terminating newline */
+               if (buf[offset - 1] == '\n')
+                       offset--;
+       }
+       else {
+               /* Make sure there is an EOLN */
+               if (buf[offset - 1] != '\n')
+                       buf[offset++] = '\n';
+       }
+       buf[offset] = '\0';
+       return offset;
+}
+
+struct commit *pop_commit(struct commit_list **stack)
+{
+       struct commit_list *top = *stack;
+       struct commit *item = top ? top->item : NULL;
+
+       if (top) {
+               *stack = top->next;
+               free(top);
+       }
+       return item;
+}
+
+int count_parents(struct commit * commit)
+{
+        int count = 0;
+        struct commit_list * parents = commit->parents;
+        for (count=0;parents; parents=parents->next,count++)
+          ;
+        return count;
+}
+
+/*
+ * Performs an in-place topological sort on the list supplied.
+ */
+void sort_in_topological_order(struct commit_list ** list)
+{
+       struct commit_list * next = *list;
+       struct commit_list * work = NULL;
+       struct commit_list ** pptr = list;
+       struct sort_node * nodes;
+       struct sort_node * next_nodes;
+       int count = 0;
+
+       /* determine the size of the list */
+       while (next) {
+               next = next->next;
+               count++;
+       }
+       /* allocate an array to help sort the list */
+       nodes = xcalloc(count, sizeof(*nodes));
+       /* link the list to the array */
+       next_nodes = nodes;
+       next=*list;
+       while (next) {
+               next_nodes->list_item = next;
+               next->item->object.util = next_nodes;
+               next_nodes++;
+               next = next->next;
+       }
+       /* update the indegree */
+       next=*list;
+       while (next) {
+               struct commit_list * parents = next->item->parents;
+               while (parents) {
+                       struct commit * parent=parents->item;
+                       struct sort_node * pn = (struct sort_node *)parent->object.util;
+                       
+                       if (pn)
+                               pn->indegree++;
+                       parents=parents->next;
+               }
+               next=next->next;
+       }
+       /* 
+         * find the tips
+         *
+         * tips are nodes not reachable from any other node in the list 
+         * 
+         * the tips serve as a starting set for the work queue.
+         */
+       next=*list;
+       while (next) {
+               struct sort_node * node = (struct sort_node *)next->item->object.util;
+
+               if (node->indegree == 0) {
+                       commit_list_insert(next->item, &work);
+               }
+               next=next->next;
+       }
+       /* process the list in topological order */
+       while (work) {
+               struct commit * work_item = pop_commit(&work);
+               struct sort_node * work_node = (struct sort_node *)work_item->object.util;
+               struct commit_list * parents = work_item->parents;
+
+               while (parents) {
+                       struct commit * parent=parents->item;
+                       struct sort_node * pn = (struct sort_node *)parent->object.util;
+                       
+                       if (pn) {
+                               /* 
+                                * parents are only enqueued for emission 
+                                 * when all their children have been emitted thereby
+                                 * guaranteeing topological order.
+                                 */
+                               pn->indegree--;
+                               if (!pn->indegree) 
+                                       commit_list_insert(parent, &work);
+                       }
+                       parents=parents->next;
+               }
+               /*
+                 * work_item is a commit all of whose children
+                 * have already been emitted. we can emit it now.
+                 */
+               *pptr = work_node->list_item;
+               pptr = &(*pptr)->next;
+               *pptr = NULL;
+               work_item->object.util = NULL;
+       }
+       free(nodes);
+}