Merge branch 'lt/fix-sol-pack' into next
[git/git.git] / pack-objects.c
index 7d62477..d7ba938 100644 (file)
@@ -3,6 +3,7 @@
 #include "delta.h"
 #include "pack.h"
 #include "csum-file.h"
+#include "tree-walk.h"
 #include <sys/time.h>
 #include <signal.h>
 
@@ -27,6 +28,10 @@ struct object_entry {
        struct object_entry *delta_sibling; /* other deltified objects who
                                             * uses the same base as me
                                             */
+       int preferred_base;     /* we do not pack this, but is encouraged to
+                                * be used as the base objectto delta huge
+                                * objects against.
+                                */
 };
 
 /*
@@ -49,7 +54,7 @@ static int local = 0;
 static int incremental = 0;
 static struct object_entry **sorted_by_sha, **sorted_by_type;
 static struct object_entry *objects = NULL;
-static int nr_objects = 0, nr_alloc = 0;
+static int nr_objects = 0, nr_alloc = 0, nr_result = 0;
 static const char *base_name;
 static unsigned char pack_file_sha1[20];
 static int progress = 1;
@@ -91,7 +96,7 @@ static int reused_delta = 0;
 
 static int pack_revindex_ix(struct packed_git *p)
 {
-       unsigned int ui = (unsigned int) p;
+       unsigned long ui = (unsigned long)p;
        int i;
 
        ui = ui ^ (ui >> 16); /* defeat structure alignment */
@@ -231,7 +236,8 @@ static int encode_header(enum object_type type, unsigned long size, unsigned cha
        return n;
 }
 
-static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
+static unsigned long write_object(struct sha1file *f,
+                                 struct object_entry *entry)
 {
        unsigned long size;
        char type[10];
@@ -241,6 +247,9 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry
        enum object_type obj_type;
        int to_reuse = 0;
 
+       if (entry->preferred_base)
+               return 0;
+
        obj_type = entry->type;
        if (! entry->in_pack)
                to_reuse = 0;   /* can't reuse what we don't have */
@@ -335,20 +344,22 @@ static void write_pack_file(void)
                do_progress = progress;
        }
        if (do_progress)
-               fprintf(stderr, "Writing %d objects.\n", nr_objects);
+               fprintf(stderr, "Writing %d objects.\n", nr_result);
 
        hdr.hdr_signature = htonl(PACK_SIGNATURE);
        hdr.hdr_version = htonl(PACK_VERSION);
-       hdr.hdr_entries = htonl(nr_objects);
+       hdr.hdr_entries = htonl(nr_result);
        sha1write(f, &hdr, sizeof(hdr));
        offset = sizeof(hdr);
+       if (!nr_result)
+               goto done;
        for (i = 0; i < nr_objects; i++) {
                offset = write_one(f, objects + i, offset);
                if (do_progress) {
-                       unsigned percent = written * 100 / nr_objects;
+                       unsigned percent = written * 100 / nr_result;
                        if (progress_update || percent != last_percent) {
                                fprintf(stderr, "%4u%% (%u/%u) done\r",
-                                       percent, written, nr_objects);
+                                       percent, written, nr_result);
                                progress_update = 0;
                                last_percent = percent;
                        }
@@ -356,16 +367,17 @@ static void write_pack_file(void)
        }
        if (do_progress)
                fputc('\n', stderr);
-
+ done:
        sha1close(f, pack_file_sha1, 1);
 }
 
 static void write_index_file(void)
 {
        int i;
-       struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
+       struct sha1file *f = sha1create("%s-%s.%s", base_name,
+                                       sha1_to_hex(object_list_sha1), "idx");
        struct object_entry **list = sorted_by_sha;
-       struct object_entry **last = list + nr_objects;
+       struct object_entry **last = list + nr_result;
        unsigned int array[256];
 
        /*
@@ -390,7 +402,7 @@ static void write_index_file(void)
         * Write the actual SHA1 entries..
         */
        list = sorted_by_sha;
-       for (i = 0; i < nr_objects; i++) {
+       for (i = 0; i < nr_result; i++) {
                struct object_entry *entry = *list++;
                unsigned int offset = htonl(entry->offset);
                sha1write(f, &offset, 4);
@@ -400,27 +412,139 @@ static void write_index_file(void)
        sha1close(f, NULL, 1);
 }
 
-static int add_object_entry(unsigned char *sha1, unsigned int hash)
+static int locate_object_entry_hash(const unsigned char *sha1)
+{
+       int i;
+       unsigned int ui;
+       memcpy(&ui, sha1, sizeof(unsigned int));
+       i = ui % object_ix_hashsz;
+       while (0 < object_ix[i]) {
+               if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
+                       return i;
+               if (++i == object_ix_hashsz)
+                       i = 0;
+       }
+       return -1 - i;
+}
+
+static struct object_entry *locate_object_entry(const unsigned char *sha1)
+{
+       int i;
+
+       if (!object_ix_hashsz)
+               return NULL;
+
+       i = locate_object_entry_hash(sha1);
+       if (0 <= i)
+               return &objects[object_ix[i]-1];
+       return NULL;
+}
+
+static void rehash_objects(void)
+{
+       int i;
+       struct object_entry *oe;
+
+       object_ix_hashsz = nr_objects * 3;
+       if (object_ix_hashsz < 1024)
+               object_ix_hashsz = 1024;
+       object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
+       object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
+       for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
+               int ix = locate_object_entry_hash(oe->sha1);
+               if (0 <= ix)
+                       continue;
+               ix = -1 - ix;
+               object_ix[ix] = i + 1;
+       }
+}
+
+struct name_path {
+       struct name_path *up;
+       const char *elem;
+       int len;
+};
+
+#define DIRBITS 12
+
+static unsigned name_hash(struct name_path *path, const char *name)
+{
+       struct name_path *p = path;
+       const char *n = name + strlen(name);
+       unsigned hash = 0, name_hash = 0, name_done = 0;
+
+       if (n != name && n[-1] == '\n')
+               n--;
+       while (name <= --n) {
+               unsigned char c = *n;
+               if (c == '/' && !name_done) {
+                       name_hash = hash;
+                       name_done = 1;
+                       hash = 0;
+               }
+               hash = hash * 11 + c;
+       }
+       if (!name_done) {
+               name_hash = hash;
+               hash = 0;
+       }
+       for (p = path; p; p = p->up) {
+               hash = hash * 11 + '/';
+               n = p->elem + p->len;
+               while (p->elem <= --n) {
+                       unsigned char c = *n;
+                       hash = hash * 11 + c;
+               }
+       }
+       /*
+        * Make sure "Makefile" and "t/Makefile" are hashed separately
+        * but close enough.
+        */
+       hash = (name_hash<<DIRBITS) | (hash & ((1U<<DIRBITS )-1));
+
+       if (0) { /* debug */
+               n = name + strlen(name);
+               if (n != name && n[-1] == '\n')
+                       n--;
+               while (name <= --n)
+                       fputc(*n, stderr);
+               for (p = path; p; p = p->up) {
+                       fputc('/', stderr);
+                       n = p->elem + p->len;
+                       while (p->elem <= --n)
+                               fputc(*n, stderr);
+               }
+               fprintf(stderr, "\t%08x\n", hash);
+       }
+       return hash;
+}
+
+static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 {
        unsigned int idx = nr_objects;
        struct object_entry *entry;
        struct packed_git *p;
        unsigned int found_offset = 0;
        struct packed_git *found_pack = NULL;
-
-       for (p = packed_git; p; p = p->next) {
-               struct pack_entry e;
-               if (find_pack_entry_one(sha1, &e, p)) {
-                       if (incremental)
-                               return 0;
-                       if (local && !p->pack_local)
-                               return 0;
-                       if (!found_pack) {
-                               found_offset = e.offset;
-                               found_pack = e.p;
+       int ix, status = 0;
+
+       if (!exclude) {
+               for (p = packed_git; p; p = p->next) {
+                       struct pack_entry e;
+                       if (find_pack_entry_one(sha1, &e, p)) {
+                               if (incremental)
+                                       return 0;
+                               if (local && !p->pack_local)
+                                       return 0;
+                               if (!found_pack) {
+                                       found_offset = e.offset;
+                                       found_pack = e.p;
+                               }
                        }
                }
        }
+       if ((entry = locate_object_entry(sha1)) != NULL)
+               goto already_added;
 
        if (idx >= nr_alloc) {
                unsigned int needed = (idx + 1024) * 3 / 2;
@@ -428,45 +552,94 @@ static int add_object_entry(unsigned char *sha1, unsigned int hash)
                nr_alloc = needed;
        }
        entry = objects + idx;
+       nr_objects = idx + 1;
        memset(entry, 0, sizeof(*entry));
        memcpy(entry->sha1, sha1, 20);
        entry->hash = hash;
-       if (found_pack) {
-               entry->in_pack = found_pack;
-               entry->in_pack_offset = found_offset;
+
+       if (object_ix_hashsz * 3 <= nr_objects * 4)
+               rehash_objects();
+       else {
+               ix = locate_object_entry_hash(entry->sha1);
+               if (0 <= ix)
+                       die("internal error in object hashing.");
+               object_ix[-1 - ix] = idx + 1;
        }
-       nr_objects = idx+1;
-       return 1;
+       status = 1;
+
+ already_added:
+       if (progress_update) {
+               fprintf(stderr, "Counting objects...%d\r", nr_objects);
+               progress_update = 0;
+       }
+       if (exclude)
+               entry->preferred_base = 1;
+       else {
+               if (found_pack) {
+                       entry->in_pack = found_pack;
+                       entry->in_pack_offset = found_offset;
+               }
+       }
+       return status;
 }
 
-static int locate_object_entry_hash(unsigned char *sha1)
+static void add_pbase_tree(struct tree_desc *tree, struct name_path *up)
 {
-       int i;
-       unsigned int ui;
-       memcpy(&ui, sha1, sizeof(unsigned int));
-       i = ui % object_ix_hashsz;
-       while (0 < object_ix[i]) {
-               if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
-                       return i;
-               if (++i == object_ix_hashsz)
-                       i = 0;
+       while (tree->size) {
+               const unsigned char *sha1;
+               const char *name;
+               unsigned mode, hash;
+               unsigned long size;
+               char type[20];
+
+               sha1 = tree_entry_extract(tree, &name, &mode);
+               update_tree_entry(tree);
+               if (!has_sha1_file(sha1))
+                       continue;
+               if (sha1_object_info(sha1, type, &size))
+                       continue;
+
+               hash = name_hash(up, name);
+               if (!add_object_entry(sha1, hash, 1))
+                       continue;
+
+               if (!strcmp(type, "tree")) {
+                       struct tree_desc sub;
+                       void *elem;
+                       struct name_path me;
+
+                       elem = read_sha1_file(sha1, type, &sub.size);
+                       sub.buf = elem;
+                       if (sub.buf) {
+                               me.up = up;
+                               me.elem = name;
+                               me.len = strlen(name);
+                               add_pbase_tree(&sub, &me);
+                               free(elem);
+                       }
+               }
        }
-       return -1 - i;
 }
 
-static struct object_entry *locate_object_entry(unsigned char *sha1)
+static void add_preferred_base(unsigned char *sha1)
 {
-       int i = locate_object_entry_hash(sha1);
-       if (0 <= i)
-               return &objects[object_ix[i]-1];
-       return NULL;
+       struct tree_desc tree;
+       void *elem;
+
+       elem = read_object_with_reference(sha1, "tree", &tree.size, NULL);
+       tree.buf = elem;
+       if (!tree.buf)
+               return;
+       if (add_object_entry(sha1, name_hash(NULL, ""), 1))
+               add_pbase_tree(&tree, NULL);
+       free(elem);
 }
 
 static void check_object(struct object_entry *entry)
 {
        char type[20];
 
-       if (entry->in_pack) {
+       if (entry->in_pack && !entry->preferred_base) {
                unsigned char base[20];
                unsigned long size;
                struct object_entry *base_entry;
@@ -485,7 +658,8 @@ static void check_object(struct object_entry *entry)
                 */
                if (!no_reuse_delta &&
                    entry->in_pack_type == OBJ_DELTA &&
-                   (base_entry = locate_object_entry(base))) {
+                   (base_entry = locate_object_entry(base)) &&
+                   (!base_entry->preferred_base)) {
 
                        /* Depth value does not matter - find_deltas()
                         * will never consider reused delta as the
@@ -523,25 +697,6 @@ static void check_object(struct object_entry *entry)
                    sha1_to_hex(entry->sha1), type);
 }
 
-static void hash_objects(void)
-{
-       int i;
-       struct object_entry *oe;
-
-       object_ix_hashsz = nr_objects * 2;
-       object_ix = xcalloc(sizeof(int), object_ix_hashsz);
-       for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
-               int ix = locate_object_entry_hash(oe->sha1);
-               if (0 <= ix) {
-                       error("the same object '%s' added twice",
-                             sha1_to_hex(oe->sha1));
-                       continue;
-               }
-               ix = -1 - ix;
-               object_ix[ix] = i + 1;
-       }
-}
-
 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 {
        struct object_entry *child = me->delta_child;
@@ -560,14 +715,26 @@ static void get_object_details(void)
        int i;
        struct object_entry *entry;
 
-       hash_objects();
        prepare_pack_ix();
        for (i = 0, entry = objects; i < nr_objects; i++, entry++)
                check_object(entry);
-       for (i = 0, entry = objects; i < nr_objects; i++, entry++)
-               if (!entry->delta && entry->delta_child)
-                       entry->delta_limit =
-                               check_delta_limit(entry, 1);
+
+       if (nr_objects == nr_result) {
+               /*
+                * Depth of objects that depend on the entry -- this
+                * is subtracted from depth-max to break too deep
+                * delta chain because of delta data reusing.
+                * However, we loosen this restriction when we know we
+                * are creating a thin pack -- it will have to be
+                * expanded on the other end anyway, so do not
+                * artificially cut the delta chain and let it go as
+                * deep as it wants.
+                */
+               for (i = 0, entry = objects; i < nr_objects; i++, entry++)
+                       if (!entry->delta && entry->delta_child)
+                               entry->delta_limit =
+                                       check_delta_limit(entry, 1);
+       }
 }
 
 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
@@ -598,6 +765,24 @@ static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
        return memcmp(a->sha1, b->sha1, 20);
 }
 
+static struct object_entry **create_final_object_list(void)
+{
+       struct object_entry **list;
+       int i, j;
+
+       for (i = nr_result = 0; i < nr_objects; i++)
+               if (!objects[i].preferred_base)
+                       nr_result++;
+       list = xmalloc(nr_result * sizeof(struct object_entry *));
+       for (i = j = 0; i < nr_objects; i++) {
+               if (!objects[i].preferred_base)
+                       list[j++] = objects + i;
+       }
+       current_sort = sha1_sort;
+       qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
+       return list;
+}
+
 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
 {
        if (a->type < b->type)
@@ -608,6 +793,10 @@ static int type_size_sort(const struct object_entry *a, const struct object_entr
                return -1;
        if (a->hash > b->hash)
                return 1;
+       if (a->preferred_base < b->preferred_base)
+               return -1;
+       if (a->preferred_base > b->preferred_base)
+               return 1;
        if (a->size < b->size)
                return -1;
        if (a->size > b->size)
@@ -640,9 +829,15 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
        if (cur_entry->type != old_entry->type)
                return -1;
 
-       /* If the current object is at edge, take the depth the objects
-        * that depend on the current object into account -- otherwise
-        * they would become too deep.
+       /* We do not compute delta to *create* objects we are not
+        * going to pack.
+        */
+       if (cur_entry->preferred_base)
+               return -1;
+
+       /* If the current object is at pack edge, take the depth the
+        * objects that depend on the current object into account --
+        * otherwise they would become too deep.
         */
        if (cur_entry->delta_child) {
                if (max_depth <= cur_entry->delta_limit)
@@ -651,11 +846,10 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
        }
 
        size = cur_entry->size;
-       if (size < 50)
-               return -1;
        oldsize = old_entry->size;
        sizediff = oldsize > size ? oldsize - size : size - oldsize;
-       if (sizediff > size / 8)
+
+       if (size < 50)
                return -1;
        if (old_entry->depth >= max_depth)
                return 0;
@@ -700,7 +894,7 @@ static void find_deltas(struct object_entry **list, int window, int depth)
        i = nr_objects;
        idx = 0;
        if (progress)
-               fprintf(stderr, "Deltifying %d objects.\n", nr_objects);
+               fprintf(stderr, "Deltifying %d objects.\n", nr_result);
 
        while (--i >= 0) {
                struct object_entry *entry = list[i];
@@ -709,12 +903,14 @@ static void find_deltas(struct object_entry **list, int window, int depth)
                char type[10];
                int j;
 
-               processed++;
+               if (!entry->preferred_base)
+                       processed++;
+
                if (progress) {
-                       unsigned percent = processed * 100 / nr_objects;
+                       unsigned percent = processed * 100 / nr_result;
                        if (percent != last_percent || progress_update) {
                                fprintf(stderr, "%4u%% (%u/%u) done\r",
-                                       percent, processed, nr_objects);
+                                       percent, processed, nr_result);
                                progress_update = 0;
                                last_percent = percent;
                        }
@@ -744,6 +940,15 @@ static void find_deltas(struct object_entry **list, int window, int depth)
                        if (try_delta(n, m, depth) < 0)
                                break;
                }
+#if 0
+               /* if we made n a delta, and if n is already at max
+                * depth, leaving it in the window is pointless.  we
+                * should evict it first.
+                * ... in theory only; somehow this makes things worse.
+                */
+               if (entry->delta && depth <= entry->depth)
+                       continue;
+#endif
                idx++;
                if (idx >= window)
                        idx = 0;
@@ -906,8 +1111,6 @@ int main(int argc, char **argv)
        }
 
        for (;;) {
-               unsigned int hash;
-               char *p;
                unsigned char sha1[20];
 
                if (!fgets(line, sizeof(line), stdin)) {
@@ -921,40 +1124,38 @@ int main(int argc, char **argv)
                        continue;
                }
 
-               if (progress_update) {
-                       fprintf(stderr, "Counting objects...%d\r", nr_objects);
-                       progress_update = 0;
+               if (line[0] == '-') {
+                       if (get_sha1_hex(line+1, sha1))
+                               die("expected edge sha1, got garbage:\n %s",
+                                   line+1);
+                       add_preferred_base(sha1);
+                       continue;
                }
                if (get_sha1_hex(line, sha1))
                        die("expected sha1, got garbage:\n %s", line);
-               hash = 0;
-               p = line+40;
-               while (*p) {
-                       unsigned char c = *p++;
-                       if (isspace(c))
-                               continue;
-                       hash = hash * 11 + c;
-               }
-               add_object_entry(sha1, hash);
+               add_object_entry(sha1, name_hash(NULL, line+41), 0);
        }
        if (progress)
                fprintf(stderr, "Done counting %d objects.\n", nr_objects);
-       if (non_empty && !nr_objects)
+       sorted_by_sha = create_final_object_list();
+       if (non_empty && !nr_result)
                return 0;
 
-       sorted_by_sha = create_sorted_list(sha1_sort);
        SHA1_Init(&ctx);
        list = sorted_by_sha;
-       for (i = 0; i < nr_objects; i++) {
+       for (i = 0; i < nr_result; i++) {
                struct object_entry *entry = *list++;
                SHA1_Update(&ctx, entry->sha1, 20);
        }
        SHA1_Final(object_list_sha1, &ctx);
+       if (progress && (nr_objects != nr_result))
+               fprintf(stderr, "Result has %d objects.\n", nr_result);
 
        if (reuse_cached_pack(object_list_sha1, pack_to_stdout))
                ;
        else {
-               prepare_pack(window, depth);
+               if (nr_result)
+                       prepare_pack(window, depth);
                if (progress && pack_to_stdout) {
                        /* the other end usually displays progress itself */
                        struct itimerval v = {{0,},};
@@ -970,6 +1171,6 @@ int main(int argc, char **argv)
        }
        if (progress)
                fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
-                       nr_objects, written, written_delta, reused, reused_delta);
+                       nr_result, written, written_delta, reused, reused_delta);
        return 0;
 }