Merge branch 'maint'
[gitweb.git] / sha1_file.c
index 57a9b532cfbfb56d4812555fb0079bcfe73f42eb..940bab561254842fd50c59cf9284a8c878cb3fd8 100644 (file)
@@ -349,6 +349,7 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 static void read_info_alternates(const char * relative_base, int depth)
 {
        char *map;
+       size_t mapsz;
        struct stat st;
        char path[PATH_MAX];
        int fd;
@@ -361,12 +362,13 @@ static void read_info_alternates(const char * relative_base, int depth)
                close(fd);
                return;
        }
-       map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       mapsz = xsize_t(st.st_size);
+       map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
 
-       link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
+       link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
 
-       munmap(map, st.st_size);
+       munmap(map, mapsz);
 }
 
 void prepare_alt_odb(void)
@@ -430,48 +432,50 @@ void pack_report()
                pack_mapped, peak_pack_mapped);
 }
 
-static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
-                               void **idx_map_)
+static int check_packed_git_idx(const char *path,  struct packed_git *p)
 {
        void *idx_map;
-       uint32_t *index;
-       unsigned long idx_size;
-       int nr, i;
+       struct pack_idx_header *hdr;
+       size_t idx_size;
+       uint32_t nr, i, *index;
        int fd = open(path, O_RDONLY);
        struct stat st;
+
        if (fd < 0)
                return -1;
        if (fstat(fd, &st)) {
                close(fd);
                return -1;
        }
-       idx_size = st.st_size;
+       idx_size = xsize_t(st.st_size);
+       if (idx_size < 4 * 256 + 20 + 20) {
+               close(fd);
+               return error("index file %s is too small", path);
+       }
        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
 
-       index = idx_map;
-       *idx_map_ = idx_map;
-       *idx_size_ = idx_size;
-
-       /* check index map */
-       if (idx_size < 4*256 + 20 + 20)
-               return error("index file %s is too small", path);
-
        /* a future index format would start with this, as older git
         * binaries would fail the non-monotonic index check below.
         * give a nicer warning to the user if we can.
         */
-       if (index[0] == htonl(PACK_IDX_SIGNATURE))
+       hdr = idx_map;
+       if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
+               munmap(idx_map, idx_size);
                return error("index file %s is a newer version"
                        " and is not supported by this binary"
                        " (try upgrading GIT to a newer version)",
                        path);
+       }
 
        nr = 0;
+       index = idx_map;
        for (i = 0; i < 256; i++) {
-               unsigned int n = ntohl(index[i]);
-               if (n < nr)
+               uint32_t n = ntohl(index[i]);
+               if (n < nr) {
+                       munmap(idx_map, idx_size);
                        return error("non-monotonic index %s", path);
+               }
                nr = n;
        }
 
@@ -482,9 +486,14 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
         *  - 20-byte SHA1 of the packfile
         *  - 20-byte SHA1 file checksum
         */
-       if (idx_size != 4*256 + nr * 24 + 20 + 20)
+       if (idx_size != 4*256 + nr * 24 + 20 + 20) {
+               munmap(idx_map, idx_size);
                return error("wrong index file size in %s", path);
+       }
 
+       p->index_version = 1;
+       p->index_data = idx_map;
+       p->index_size = idx_size;
        return 0;
 }
 
@@ -605,7 +614,7 @@ static int open_packed_git_1(struct packed_git *p)
                return error("end of packfile %s is unavailable", p->pack_name);
        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
                return error("packfile %s signature is unavailable", p->pack_name);
-       idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
+       idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
        if (hashcmp(sha1, idx_sha1))
                return error("packfile %s does not match index", p->pack_name);
        return 0;
@@ -622,7 +631,7 @@ static int open_packed_git(struct packed_git *p)
        return -1;
 }
 
-static int in_window(struct pack_window *win, unsigned long offset)
+static int in_window(struct pack_window *win, off_t offset)
 {
        /* We must promise at least 20 bytes (one hash) after the
         * offset is available from this window, otherwise the offset
@@ -637,7 +646,7 @@ static int in_window(struct pack_window *win, unsigned long offset)
 
 unsigned char* use_pack(struct packed_git *p,
                struct pack_window **w_cursor,
-               unsigned long offset,
+               off_t offset,
                unsigned int *left)
 {
        struct pack_window *win = *w_cursor;
@@ -662,11 +671,13 @@ unsigned char* use_pack(struct packed_git *p,
                }
                if (!win) {
                        size_t window_align = packed_git_window_size / 2;
+                       off_t len;
                        win = xcalloc(1, sizeof(*win));
                        win->offset = (offset / window_align) * window_align;
-                       win->len = p->pack_size - win->offset;
-                       if (win->len > packed_git_window_size)
-                               win->len = packed_git_window_size;
+                       len = p->pack_size - win->offset;
+                       if (len > packed_git_window_size)
+                               len = packed_git_window_size;
+                       win->len = (size_t)len;
                        pack_mapped += win->len;
                        while (packed_git_limit < pack_mapped
                                && unuse_one_window(p))
@@ -695,41 +706,41 @@ unsigned char* use_pack(struct packed_git *p,
        }
        offset -= win->offset;
        if (left)
-               *left = win->len - offset;
+               *left = win->len - xsize_t(offset);
        return win->base + offset;
 }
 
-struct packed_git *add_packed_git(char *path, int path_len, int local)
+struct packed_git *add_packed_git(const char *path, int path_len, int local)
 {
        struct stat st;
-       struct packed_git *p;
-       unsigned long idx_size;
-       void *idx_map;
-       unsigned char sha1[20];
+       struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2);
 
-       if (check_packed_git_idx(path, &idx_size, &idx_map))
+       /*
+        * Make sure a corresponding .pack file exists and that
+        * the index looks sane.
+        */
+       path_len -= strlen(".idx");
+       if (path_len < 1)
                return NULL;
-
-       /* do we have a corresponding .pack file? */
-       strcpy(path + path_len - 4, ".pack");
-       if (stat(path, &st) || !S_ISREG(st.st_mode)) {
-               munmap(idx_map, idx_size);
+       memcpy(p->pack_name, path, path_len);
+       strcpy(p->pack_name + path_len, ".pack");
+       if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode) ||
+           check_packed_git_idx(path, p)) {
+               free(p);
                return NULL;
        }
+
        /* ok, it looks sane as far as we can check without
         * actually mapping the pack file.
         */
-       p = xmalloc(sizeof(*p) + path_len + 2);
-       strcpy(p->pack_name, path);
-       p->index_size = idx_size;
        p->pack_size = st.st_size;
-       p->index_base = idx_map;
        p->next = NULL;
        p->windows = NULL;
        p->pack_fd = -1;
        p->pack_local = local;
-       if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
-               hashcpy(p->sha1, sha1);
+       p->mtime = st.st_mtime;
+       if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
+               hashclr(p->sha1);
        return p;
 }
 
@@ -739,23 +750,19 @@ struct packed_git *parse_pack_index(unsigned char *sha1)
        return parse_pack_index_file(sha1, path);
 }
 
-struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
+struct packed_git *parse_pack_index_file(const unsigned char *sha1,
+                                        const char *idx_path)
 {
-       struct packed_git *p;
-       unsigned long idx_size;
-       void *idx_map;
-       char *path;
+       const char *path = sha1_pack_name(sha1);
+       struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
 
-       if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
+       if (check_packed_git_idx(idx_path, p)) {
+               free(p);
                return NULL;
+       }
 
-       path = sha1_pack_name(sha1);
-
-       p = xmalloc(sizeof(*p) + strlen(path) + 2);
        strcpy(p->pack_name, path);
-       p->index_size = idx_size;
        p->pack_size = 0;
-       p->index_base = idx_map;
        p->next = NULL;
        p->windows = NULL;
        p->pack_fd = -1;
@@ -812,6 +819,60 @@ static void prepare_packed_git_one(char *objdir, int local)
        closedir(dir);
 }
 
+static int sort_pack(const void *a_, const void *b_)
+{
+       struct packed_git *a = *((struct packed_git **)a_);
+       struct packed_git *b = *((struct packed_git **)b_);
+       int st;
+
+       /*
+        * Local packs tend to contain objects specific to our
+        * variant of the project than remote ones.  In addition,
+        * remote ones could be on a network mounted filesystem.
+        * Favor local ones for these reasons.
+        */
+       st = a->pack_local - b->pack_local;
+       if (st)
+               return -st;
+
+       /*
+        * Younger packs tend to contain more recent objects,
+        * and more recent objects tend to get accessed more
+        * often.
+        */
+       if (a->mtime < b->mtime)
+               return 1;
+       else if (a->mtime == b->mtime)
+               return 0;
+       return -1;
+}
+
+static void rearrange_packed_git(void)
+{
+       struct packed_git **ary, *p;
+       int i, n;
+
+       for (n = 0, p = packed_git; p; p = p->next)
+               n++;
+       if (n < 2)
+               return;
+
+       /* prepare an array of packed_git for easier sorting */
+       ary = xcalloc(n, sizeof(struct packed_git *));
+       for (n = 0, p = packed_git; p; p = p->next)
+               ary[n++] = p;
+
+       qsort(ary, n, sizeof(struct packed_git *), sort_pack);
+
+       /* link them back again */
+       for (i = 0; i < n - 1; i++)
+               ary[i]->next = ary[i + 1];
+       ary[n - 1]->next = NULL;
+       packed_git = ary[0];
+
+       free(ary);
+}
+
 static int prepare_packed_git_run_once = 0;
 void prepare_packed_git(void)
 {
@@ -826,6 +887,7 @@ void prepare_packed_git(void)
                prepare_packed_git_one(alt->base, 0);
                alt->name[-1] = '/';
        }
+       rearrange_packed_git();
        prepare_packed_git_run_once = 1;
 }
 
@@ -871,9 +933,9 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
                 */
                sha1_file_open_flag = 0;
        }
-       map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       *size = xsize_t(st.st_size);
+       map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
-       *size = st.st_size;
        return map;
 }
 
@@ -952,30 +1014,54 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
 
        /* And generate the fake traditional header */
        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
-                                        type_names[type], size);
+                                        typename(type), size);
        return 0;
 }
 
-static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
+static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 {
        int bytes = strlen(buffer) + 1;
        unsigned char *buf = xmalloc(1+size);
        unsigned long n;
+       int status = Z_OK;
 
        n = stream->total_out - bytes;
        if (n > size)
                n = size;
        memcpy(buf, (char *) buffer + bytes, n);
        bytes = n;
-       if (bytes < size) {
+       if (bytes <= size) {
+               /*
+                * The above condition must be (bytes <= size), not
+                * (bytes < size).  In other words, even though we
+                * expect no more output and set avail_out to zer0,
+                * the input zlib stream may have bytes that express
+                * "this concludes the stream", and we *do* want to
+                * eat that input.
+                *
+                * Otherwise we would not be able to test that we
+                * consumed all the input to reach the expected size;
+                * we also want to check that zlib tells us that all
+                * went well with status == Z_STREAM_END at the end.
+                */
                stream->next_out = buf + bytes;
                stream->avail_out = size - bytes;
-               while (inflate(stream, Z_FINISH) == Z_OK)
-                       /* nothing */;
+               while (status == Z_OK)
+                       status = inflate(stream, Z_FINISH);
        }
        buf[size] = 0;
-       inflateEnd(stream);
-       return buf;
+       if (status == Z_STREAM_END && !stream->avail_in) {
+               inflateEnd(stream);
+               return buf;
+       }
+
+       if (status < 0)
+               error("corrupt loose object '%s'", sha1_to_hex(sha1));
+       else if (stream->avail_in)
+               error("garbage at end of loose object '%s'",
+                     sha1_to_hex(sha1));
+       free(buf);
+       return NULL;
 }
 
 /*
@@ -983,26 +1069,27 @@ static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size
  * too permissive for what we want to check. So do an anal
  * object header parse by hand.
  */
-static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
+static int parse_sha1_header(const char *hdr, unsigned long *sizep)
 {
+       char type[10];
        int i;
        unsigned long size;
 
        /*
         * The type can be at most ten bytes (including the 
         * terminating '\0' that we add), and is followed by
-        * a space. 
+        * a space.
         */
-       i = 10;
+       i = 0;
        for (;;) {
                char c = *hdr++;
                if (c == ' ')
                        break;
-               if (!--i)
+               type[i++] = c;
+               if (i >= sizeof(type))
                        return -1;
-               *type++ = c;
        }
-       *type = 0;
+       type[i] = 0;
 
        /*
         * The length must follow immediately, and be in canonical
@@ -1025,31 +1112,30 @@ static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
        /*
         * The length must be followed by a zero byte
         */
-       return *hdr ? -1 : 0;
+       return *hdr ? -1 : type_from_string(type);
 }
 
-void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
+static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
 {
        int ret;
        z_stream stream;
        char hdr[8192];
 
        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
-       if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
+       if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
                return NULL;
 
-       return unpack_sha1_rest(&stream, hdr, *size);
+       return unpack_sha1_rest(&stream, hdr, *size, sha1);
 }
 
-static unsigned long get_delta_base(struct packed_git *p,
+static off_t get_delta_base(struct packed_git *p,
                                    struct pack_window **w_curs,
-                                   unsigned long offset,
-                                   enum object_type kind,
-                                   unsigned long delta_obj_offset,
-                                   unsigned long *base_obj_offset)
+                                   off_t *curpos,
+                                   enum object_type type,
+                                   off_t delta_obj_offset)
 {
-       unsigned char *base_info = use_pack(p, w_curs, offset, NULL);
-       unsigned long base_offset;
+       unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
+       off_t base_offset;
 
        /* use_pack() assured us we have [base_info, base_info + 20)
         * as a range that we can look at without walking off the
@@ -1057,7 +1143,7 @@ static unsigned long get_delta_base(struct packed_git *p,
         * that is assured.  An OFS_DELTA longer than the hash size
         * is stupid, as then a REF_DELTA would be smaller to store.
         */
-       if (kind == OBJ_OFS_DELTA) {
+       if (type == OBJ_OFS_DELTA) {
                unsigned used = 0;
                unsigned char c = base_info[used++];
                base_offset = c & 127;
@@ -1071,49 +1157,43 @@ static unsigned long get_delta_base(struct packed_git *p,
                base_offset = delta_obj_offset - base_offset;
                if (base_offset >= delta_obj_offset)
                        die("delta base offset out of bound");
-               offset += used;
-       } else if (kind == OBJ_REF_DELTA) {
+               *curpos += used;
+       } else if (type == OBJ_REF_DELTA) {
                /* The base entry _must_ be in the same pack */
                base_offset = find_pack_entry_one(base_info, p);
                if (!base_offset)
                        die("failed to find delta-pack base object %s",
                                sha1_to_hex(base_info));
-               offset += 20;
+               *curpos += 20;
        } else
                die("I am totally screwed");
-       *base_obj_offset = base_offset;
-       return offset;
+       return base_offset;
 }
 
 /* forward declaration for a mutually recursive function */
-static int packed_object_info(struct packed_git *p, unsigned long offset,
-                             char *type, unsigned long *sizep);
+static int packed_object_info(struct packed_git *p, off_t offset,
+                             unsigned long *sizep);
 
 static int packed_delta_info(struct packed_git *p,
                             struct pack_window **w_curs,
-                            unsigned long offset,
-                            enum object_type kind,
-                            unsigned long obj_offset,
-                            char *type,
+                            off_t curpos,
+                            enum object_type type,
+                            off_t obj_offset,
                             unsigned long *sizep)
 {
-       unsigned long base_offset;
+       off_t base_offset;
 
-       offset = get_delta_base(p, w_curs, offset, kind,
-               obj_offset, &base_offset);
+       base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
+       type = packed_object_info(p, base_offset, NULL);
 
        /* We choose to only get the type of the base object and
         * ignore potentially corrupt pack file that expects the delta
         * based on a base with a wrong size.  This saves tons of
         * inflate() calls.
         */
-       if (packed_object_info(p, base_offset, type, NULL))
-               die("cannot get info for delta-pack base");
-
        if (sizep) {
                const unsigned char *data;
                unsigned char delta_head[20], *in;
-               unsigned long result_size;
                z_stream stream;
                int st;
 
@@ -1123,10 +1203,10 @@ static int packed_delta_info(struct packed_git *p,
 
                inflateInit(&stream);
                do {
-                       in = use_pack(p, w_curs, offset, &stream.avail_in);
+                       in = use_pack(p, w_curs, curpos, &stream.avail_in);
                        stream.next_in = in;
                        st = inflate(&stream, Z_FINISH);
-                       offset += stream.next_in - in;
+                       curpos += stream.next_in - in;
                } while ((st == Z_OK || st == Z_BUF_ERROR)
                        && stream.total_out < sizeof(delta_head));
                inflateEnd(&stream);
@@ -1143,21 +1223,21 @@ static int packed_delta_info(struct packed_git *p,
                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 
                /* Read the result size */
-               result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
-               *sizep = result_size;
+               *sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
        }
-       return 0;
+
+       return type;
 }
 
-static unsigned long unpack_object_header(struct packed_git *p,
-               struct pack_window **w_curs,
-               unsigned long offset,
-               enum object_type *type,
-               unsigned long *sizep)
+static int unpack_object_header(struct packed_git *p,
+                               struct pack_window **w_curs,
+                               off_t *curpos,
+                               unsigned long *sizep)
 {
        unsigned char *base;
        unsigned int left;
        unsigned long used;
+       enum object_type type;
 
        /* use_pack() assures us we have [base, base + 20) available
         * as a range that we can look at at.  (Its actually the hash
@@ -1165,100 +1245,98 @@ static unsigned long unpack_object_header(struct packed_git *p,
         * the maximum deflated object size is 2^137, which is just
         * insane, so we know won't exceed what we have been given.
         */
-       base = use_pack(p, w_curs, offset, &left);
-       used = unpack_object_header_gently(base, left, type, sizep);
+       base = use_pack(p, w_curs, *curpos, &left);
+       used = unpack_object_header_gently(base, left, &type, sizep);
        if (!used)
                die("object offset outside of pack file");
+       *curpos += used;
 
-       return offset + used;
+       return type;
 }
 
-void packed_object_info_detail(struct packed_git *p,
-                              unsigned long offset,
-                              char *type,
-                              unsigned long *size,
-                              unsigned long *store_size,
-                              unsigned int *delta_chain_length,
-                              unsigned char *base_sha1)
+const char *packed_object_info_detail(struct packed_git *p,
+                                     off_t obj_offset,
+                                     unsigned long *size,
+                                     unsigned long *store_size,
+                                     unsigned int *delta_chain_length,
+                                     unsigned char *base_sha1)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long obj_offset, val;
+       off_t curpos;
+       unsigned long dummy;
        unsigned char *next_sha1;
-       enum object_type kind;
+       enum object_type type;
 
        *delta_chain_length = 0;
-       obj_offset = offset;
-       offset = unpack_object_header(p, &w_curs, offset, &kind, size);
+       curpos = obj_offset;
+       type = unpack_object_header(p, &w_curs, &curpos, size);
 
        for (;;) {
-               switch (kind) {
+               switch (type) {
                default:
                        die("pack %s contains unknown object type %d",
-                           p->pack_name, kind);
+                           p->pack_name, type);
                case OBJ_COMMIT:
                case OBJ_TREE:
                case OBJ_BLOB:
                case OBJ_TAG:
-                       strcpy(type, type_names[kind]);
                        *store_size = 0; /* notyet */
                        unuse_pack(&w_curs);
-                       return;
+                       return typename(type);
                case OBJ_OFS_DELTA:
-                       get_delta_base(p, &w_curs, offset, kind,
-                               obj_offset, &offset);
+                       obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
                        if (*delta_chain_length == 0) {
-                               /* TODO: find base_sha1 as pointed by offset */
+                               /* TODO: find base_sha1 as pointed by curpos */
+                               hashclr(base_sha1);
                        }
                        break;
                case OBJ_REF_DELTA:
-                       next_sha1 = use_pack(p, &w_curs, offset, NULL);
+                       next_sha1 = use_pack(p, &w_curs, curpos, NULL);
                        if (*delta_chain_length == 0)
                                hashcpy(base_sha1, next_sha1);
-                       offset = find_pack_entry_one(next_sha1, p);
+                       obj_offset = find_pack_entry_one(next_sha1, p);
                        break;
                }
-               obj_offset = offset;
-               offset = unpack_object_header(p, &w_curs, offset, &kind, &val);
                (*delta_chain_length)++;
+               curpos = obj_offset;
+               type = unpack_object_header(p, &w_curs, &curpos, &dummy);
        }
 }
 
-static int packed_object_info(struct packed_git *p, unsigned long offset,
-                             char *type, unsigned long *sizep)
+static int packed_object_info(struct packed_git *p, off_t obj_offset,
+                             unsigned long *sizep)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long size, obj_offset = offset;
-       enum object_type kind;
-       int r;
+       unsigned long size;
+       off_t curpos = obj_offset;
+       enum object_type type;
 
-       offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
+       type = unpack_object_header(p, &w_curs, &curpos, &size);
 
-       switch (kind) {
+       switch (type) {
        case OBJ_OFS_DELTA:
        case OBJ_REF_DELTA:
-               r = packed_delta_info(p, &w_curs, offset, kind,
-                       obj_offset, type, sizep);
-               unuse_pack(&w_curs);
-               return r;
+               type = packed_delta_info(p, &w_curs, curpos,
+                                        type, obj_offset, sizep);
+               break;
        case OBJ_COMMIT:
        case OBJ_TREE:
        case OBJ_BLOB:
        case OBJ_TAG:
-               strcpy(type, type_names[kind]);
-               unuse_pack(&w_curs);
+               if (sizep)
+                       *sizep = size;
                break;
        default:
                die("pack %s contains unknown object type %d",
-                   p->pack_name, kind);
+                   p->pack_name, type);
        }
-       if (sizep)
-               *sizep = size;
-       return 0;
+       unuse_pack(&w_curs);
+       return type;
 }
 
 static void *unpack_compressed_entry(struct packed_git *p,
                                    struct pack_window **w_curs,
-                                   unsigned long offset,
+                                   off_t curpos,
                                    unsigned long size)
 {
        int st;
@@ -1273,10 +1351,10 @@ static void *unpack_compressed_entry(struct packed_git *p,
 
        inflateInit(&stream);
        do {
-               in = use_pack(p, w_curs, offset, &stream.avail_in);
+               in = use_pack(p, w_curs, curpos, &stream.avail_in);
                stream.next_in = in;
                st = inflate(&stream, Z_FINISH);
-               offset += stream.next_in - in;
+               curpos += stream.next_in - in;
        } while (st == Z_OK || st == Z_BUF_ERROR);
        inflateEnd(&stream);
        if ((st != Z_STREAM_END) || stream.total_out != size) {
@@ -1287,94 +1365,197 @@ static void *unpack_compressed_entry(struct packed_git *p,
        return buffer;
 }
 
+#define MAX_DELTA_CACHE (256)
+
+static size_t delta_base_cached;
+
+static struct delta_base_cache_lru_list {
+       struct delta_base_cache_lru_list *prev;
+       struct delta_base_cache_lru_list *next;
+} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
+
+static struct delta_base_cache_entry {
+       struct delta_base_cache_lru_list lru;
+       void *data;
+       struct packed_git *p;
+       off_t base_offset;
+       unsigned long size;
+       enum object_type type;
+} delta_base_cache[MAX_DELTA_CACHE];
+
+static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
+{
+       unsigned long hash;
+
+       hash = (unsigned long)p + (unsigned long)base_offset;
+       hash += (hash >> 8) + (hash >> 16);
+       return hash % MAX_DELTA_CACHE;
+}
+
+static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
+       unsigned long *base_size, enum object_type *type, int keep_cache)
+{
+       void *ret;
+       unsigned long hash = pack_entry_hash(p, base_offset);
+       struct delta_base_cache_entry *ent = delta_base_cache + hash;
+
+       ret = ent->data;
+       if (ret && ent->p == p && ent->base_offset == base_offset)
+               goto found_cache_entry;
+       return unpack_entry(p, base_offset, type, base_size);
+
+found_cache_entry:
+       if (!keep_cache) {
+               ent->data = NULL;
+               ent->lru.next->prev = ent->lru.prev;
+               ent->lru.prev->next = ent->lru.next;
+               delta_base_cached -= ent->size;
+       }
+       else {
+               ret = xmalloc(ent->size + 1);
+               memcpy(ret, ent->data, ent->size);
+               ((char *)ret)[ent->size] = 0;
+       }
+       *type = ent->type;
+       *base_size = ent->size;
+       return ret;
+}
+
+static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
+{
+       if (ent->data) {
+               free(ent->data);
+               ent->data = NULL;
+               ent->lru.next->prev = ent->lru.prev;
+               ent->lru.prev->next = ent->lru.next;
+               delta_base_cached -= ent->size;
+       }
+}
+
+static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
+       void *base, unsigned long base_size, enum object_type type)
+{
+       unsigned long hash = pack_entry_hash(p, base_offset);
+       struct delta_base_cache_entry *ent = delta_base_cache + hash;
+       struct delta_base_cache_lru_list *lru;
+
+       release_delta_base_cache(ent);
+       delta_base_cached += base_size;
+
+       for (lru = delta_base_cache_lru.next;
+            delta_base_cached > delta_base_cache_limit
+            && lru != &delta_base_cache_lru;
+            lru = lru->next) {
+               struct delta_base_cache_entry *f = (void *)lru;
+               if (f->type == OBJ_BLOB)
+                       release_delta_base_cache(f);
+       }
+       for (lru = delta_base_cache_lru.next;
+            delta_base_cached > delta_base_cache_limit
+            && lru != &delta_base_cache_lru;
+            lru = lru->next) {
+               struct delta_base_cache_entry *f = (void *)lru;
+               release_delta_base_cache(f);
+       }
+
+       ent->p = p;
+       ent->base_offset = base_offset;
+       ent->type = type;
+       ent->data = base;
+       ent->size = base_size;
+       ent->lru.next = &delta_base_cache_lru;
+       ent->lru.prev = delta_base_cache_lru.prev;
+       delta_base_cache_lru.prev->next = &ent->lru;
+       delta_base_cache_lru.prev = &ent->lru;
+}
+
 static void *unpack_delta_entry(struct packed_git *p,
                                struct pack_window **w_curs,
-                               unsigned long offset,
+                               off_t curpos,
                                unsigned long delta_size,
-                               enum object_type kind,
-                               unsigned long obj_offset,
-                               char *type,
+                               off_t obj_offset,
+                               enum object_type *type,
                                unsigned long *sizep)
 {
        void *delta_data, *result, *base;
-       unsigned long result_size, base_size, base_offset;
+       unsigned long base_size;
+       off_t base_offset;
 
-       offset = get_delta_base(p, w_curs, offset, kind,
-               obj_offset, &base_offset);
-       base = unpack_entry(p, base_offset, type, &base_size);
+       base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
+       base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
        if (!base)
-               die("failed to read delta base object at %lu from %s",
-                   base_offset, p->pack_name);
+               die("failed to read delta base object"
+                   " at %"PRIuMAX" from %s",
+                   (uintmax_t)base_offset, p->pack_name);
 
-       delta_data = unpack_compressed_entry(p, w_curs, offset, delta_size);
+       delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
        result = patch_delta(base, base_size,
                             delta_data, delta_size,
-                            &result_size);
+                            sizep);
        if (!result)
                die("failed to apply delta");
        free(delta_data);
-       free(base);
-       *sizep = result_size;
+       add_delta_base_cache(p, base_offset, base, base_size, *type);
        return result;
 }
 
-void *unpack_entry(struct packed_git *p, unsigned long offset,
-                         char *type, unsigned long *sizep)
+void *unpack_entry(struct packed_git *p, off_t obj_offset,
+                  enum object_type *type, unsigned long *sizep)
 {
        struct pack_window *w_curs = NULL;
-       unsigned long size, obj_offset = offset;
-       enum object_type kind;
-       void *retval;
+       off_t curpos = obj_offset;
+       void *data;
 
-       offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
-       switch (kind) {
+       *type = unpack_object_header(p, &w_curs, &curpos, sizep);
+       switch (*type) {
        case OBJ_OFS_DELTA:
        case OBJ_REF_DELTA:
-               retval = unpack_delta_entry(p, &w_curs, offset, size,
-                       kind, obj_offset, type, sizep);
+               data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
+                                         obj_offset, type, sizep);
                break;
        case OBJ_COMMIT:
        case OBJ_TREE:
        case OBJ_BLOB:
        case OBJ_TAG:
-               strcpy(type, type_names[kind]);
-               *sizep = size;
-               retval = unpack_compressed_entry(p, &w_curs, offset, size);
+               data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
                break;
        default:
-               die("unknown object type %i in %s", kind, p->pack_name);
+               die("unknown object type %i in %s", *type, p->pack_name);
        }
        unuse_pack(&w_curs);
-       return retval;
+       return data;
 }
 
-int num_packed_objects(const struct packed_git *p)
+uint32_t num_packed_objects(const struct packed_git *p)
 {
        /* See check_packed_git_idx() */
-       return (p->index_size - 20 - 20 - 4*256) / 24;
+       return (uint32_t)((p->index_size - 20 - 20 - 4*256) / 24);
 }
 
-int nth_packed_object_sha1(const struct packed_git *p, int n,
+int nth_packed_object_sha1(const struct packed_git *p, uint32_t n,
                           unsigned char* sha1)
 {
-       void *index = p->index_base + 256;
-       if (n < 0 || num_packed_objects(p) <= n)
+       const unsigned char *index = p->index_data;
+       index += 4 * 256;
+       if (num_packed_objects(p) <= n)
                return -1;
-       hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
+       hashcpy(sha1, index + 24 * n + 4);
        return 0;
 }
 
-unsigned long find_pack_entry_one(const unsigned char *sha1,
+off_t find_pack_entry_one(const unsigned char *sha1,
                                  struct packed_git *p)
 {
-       uint32_t *level1_ofs = p->index_base;
+       const uint32_t *level1_ofs = p->index_data;
        int hi = ntohl(level1_ofs[*sha1]);
        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
-       void *index = p->index_base + 256;
+       const unsigned char *index = p->index_data;
+
+       index += 4 * 256;
 
        do {
                int mi = (lo + hi) / 2;
-               int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
+               int cmp = hashcmp(index + 24 * mi + 4, sha1);
                if (!cmp)
                        return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
                if (cmp > 0)
@@ -1406,7 +1587,7 @@ static int matches_pack_name(struct packed_git *p, const char *ig)
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
 {
        struct packed_git *p;
-       unsigned long offset;
+       off_t offset;
 
        prepare_packed_git();
 
@@ -1452,10 +1633,10 @@ struct packed_git *find_sha1_pack(const unsigned char *sha1,
                        return p;
        }
        return NULL;
-       
+
 }
 
-static int sha1_loose_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
+static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
        int status;
        unsigned long mapsize, size;
@@ -1469,38 +1650,36 @@ static int sha1_loose_object_info(const unsigned char *sha1, char *type, unsigne
        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
                status = error("unable to unpack %s header",
                               sha1_to_hex(sha1));
-       if (parse_sha1_header(hdr, type, &size) < 0)
+       else if ((status = parse_sha1_header(hdr, &size)) < 0)
                status = error("unable to parse %s header", sha1_to_hex(sha1));
-       else {
-               status = 0;
-               if (sizep)
-                       *sizep = size;
-       }
+       else if (sizep)
+               *sizep = size;
        inflateEnd(&stream);
        munmap(map, mapsize);
        return status;
 }
 
-int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
+int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
        struct pack_entry e;
 
        if (!find_pack_entry(sha1, &e, NULL)) {
                reprepare_packed_git();
                if (!find_pack_entry(sha1, &e, NULL))
-                       return sha1_loose_object_info(sha1, type, sizep);
+                       return sha1_loose_object_info(sha1, sizep);
        }
-       return packed_object_info(e.p, e.offset, type, sizep);
+       return packed_object_info(e.p, e.offset, sizep);
 }
 
-static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
+static void *read_packed_sha1(const unsigned char *sha1,
+                             enum object_type *type, unsigned long *size)
 {
        struct pack_entry e;
 
        if (!find_pack_entry(sha1, &e, NULL))
                return NULL;
        else
-               return unpack_entry(e.p, e.offset, type, size);
+               return cache_or_unpack_entry(e.p, e.offset, size, type, 1);
 }
 
 /*
@@ -1511,7 +1690,7 @@ static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned lo
  */
 static struct cached_object {
        unsigned char sha1[20];
-       const char *type;
+       enum object_type type;
        void *buf;
        unsigned long size;
 } *cached_objects;
@@ -1529,11 +1708,12 @@ static struct cached_object *find_cached_object(const unsigned char *sha1)
        return NULL;
 }
 
-int pretend_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *sha1)
+int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
+                     unsigned char *sha1)
 {
        struct cached_object *co;
 
-       hash_sha1_file(buf, len, type, sha1);
+       hash_sha1_file(buf, len, typename(type), sha1);
        if (has_sha1_file(sha1) || find_cached_object(sha1))
                return 0;
        if (cached_object_alloc <= cached_object_nr) {
@@ -1544,14 +1724,15 @@ int pretend_sha1_file(void *buf, unsigned long len, const char *type, unsigned c
        }
        co = &cached_objects[cached_object_nr++];
        co->size = len;
-       co->type = strdup(type);
+       co->type = type;
        co->buf = xmalloc(len);
        memcpy(co->buf, buf, len);
        hashcpy(co->sha1, sha1);
        return 0;
 }
 
-void *read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
+void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
+                    unsigned long *size)
 {
        unsigned long mapsize;
        void *map, *buf;
@@ -1562,7 +1743,7 @@ void *read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
                buf = xmalloc(co->size + 1);
                memcpy(buf, co->buf, co->size);
                ((char*)buf)[co->size] = 0;
-               strcpy(type, co->type);
+               *type = co->type;
                *size = co->size;
                return buf;
        }
@@ -1572,7 +1753,7 @@ void *read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
                return buf;
        map = map_sha1_file(sha1, &mapsize);
        if (map) {
-               buf = unpack_sha1_file(map, mapsize, type, size);
+               buf = unpack_sha1_file(map, mapsize, type, size, sha1);
                munmap(map, mapsize);
                return buf;
        }
@@ -1581,33 +1762,34 @@ void *read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 }
 
 void *read_object_with_reference(const unsigned char *sha1,
-                                const char *required_type,
+                                const char *required_type_name,
                                 unsigned long *size,
                                 unsigned char *actual_sha1_return)
 {
-       char type[20];
+       enum object_type type, required_type;
        void *buffer;
        unsigned long isize;
        unsigned char actual_sha1[20];
 
+       required_type = type_from_string(required_type_name);
        hashcpy(actual_sha1, sha1);
        while (1) {
                int ref_length = -1;
                const char *ref_type = NULL;
 
-               buffer = read_sha1_file(actual_sha1, type, &isize);
+               buffer = read_sha1_file(actual_sha1, &type, &isize);
                if (!buffer)
                        return NULL;
-               if (!strcmp(type, required_type)) {
+               if (type == required_type) {
                        *size = isize;
                        if (actual_sha1_return)
                                hashcpy(actual_sha1_return, actual_sha1);
                        return buffer;
                }
                /* Handle references */
-               else if (!strcmp(type, commit_type))
+               else if (type == OBJ_COMMIT)
                        ref_type = "tree ";
-               else if (!strcmp(type, tag_type))
+               else if (type == OBJ_TAG)
                        ref_type = "object ";
                else {
                        free(buffer);
@@ -1626,7 +1808,7 @@ void *read_object_with_reference(const unsigned char *sha1,
        }
 }
 
-static void write_sha1_file_prepare(void *buf, unsigned long len,
+static void write_sha1_file_prepare(const void *buf, unsigned long len,
                                     const char *type, unsigned char *sha1,
                                     char *hdr, int *hdrlen)
 {
@@ -1747,23 +1929,14 @@ static void setup_object_header(z_stream *stream, const char *type, unsigned lon
                        /* nothing */;
                return;
        }
-       if (!strcmp(type, blob_type))
-               obj_type = OBJ_BLOB;
-       else if (!strcmp(type, tree_type))
-               obj_type = OBJ_TREE;
-       else if (!strcmp(type, commit_type))
-               obj_type = OBJ_COMMIT;
-       else if (!strcmp(type, tag_type))
-               obj_type = OBJ_TAG;
-       else
-               die("trying to generate bogus object of type '%s'", type);
+       obj_type = type_from_string(type);
        hdrlen = write_binary_header(stream->next_out, obj_type, len);
        stream->total_out = hdrlen;
        stream->next_out += hdrlen;
        stream->avail_out -= hdrlen;
 }
 
-int hash_sha1_file(void *buf, unsigned long len, const char *type,
+int hash_sha1_file(const void *buf, unsigned long len, const char *type,
                    unsigned char *sha1)
 {
        char hdr[32];
@@ -1774,7 +1947,7 @@ int hash_sha1_file(void *buf, unsigned long len, const char *type,
 
 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
-       int size;
+       int size, ret;
        unsigned char *compressed;
        z_stream stream;
        unsigned char sha1[20];
@@ -1834,9 +2007,14 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
        /* Then the data itself.. */
        stream.next_in = buf;
        stream.avail_in = len;
-       while (deflate(&stream, Z_FINISH) == Z_OK)
-               /* nothing */;
-       deflateEnd(&stream);
+       ret = deflate(&stream, Z_FINISH);
+       if (ret != Z_STREAM_END)
+               die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
+
+       ret = deflateEnd(&stream);
+       if (ret != Z_OK)
+               die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
+
        size = stream.total_out;
 
        if (write_buffer(fd, compressed, size) < 0)
@@ -1858,17 +2036,17 @@ static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
        z_stream stream;
        unsigned char *unpacked;
        unsigned long len;
-       char type[20];
+       enum object_type type;
        char hdr[32];
        int hdrlen;
        void *buf;
 
        /* need to unpack and recompress it by itself */
-       unpacked = read_packed_sha1(sha1, type, &len);
+       unpacked = read_packed_sha1(sha1, &type, &len);
        if (!unpacked)
                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
 
-       hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
+       hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
 
        /* Set it up */
        memset(&stream, 0, sizeof(stream));
@@ -2078,27 +2256,27 @@ int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
        return ret;
 }
 
-int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
+int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
+            enum object_type type, const char *path)
 {
-       unsigned long size = st->st_size;
-       void *buf;
+       size_t size = xsize_t(st->st_size);
+       void *buf = NULL;
        int ret, re_allocated = 0;
 
-       buf = "";
        if (size)
                buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
        close(fd);
 
        if (!type)
-               type = blob_type;
+               type = OBJ_BLOB;
 
        /*
         * Convert blobs to git internal format
         */
-       if (!strcmp(type, blob_type)) {
+       if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
                unsigned long nsize = size;
                char *nbuf = buf;
-               if (convert_to_git(NULL, &nbuf, &nsize)) {
+               if (convert_to_git(path, &nbuf, &nsize)) {
                        if (size)
                                munmap(buf, size);
                        size = nsize;
@@ -2108,9 +2286,9 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
        }
 
        if (write_object)
-               ret = write_sha1_file(buf, size, type, sha1);
+               ret = write_sha1_file(buf, size, typename(type), sha1);
        else
-               ret = hash_sha1_file(buf, size, type, sha1);
+               ret = hash_sha1_file(buf, size, typename(type), sha1);
        if (re_allocated) {
                free(buf);
                return ret;
@@ -2124,6 +2302,7 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 {
        int fd;
        char *target;
+       size_t len;
 
        switch (st->st_mode & S_IFMT) {
        case S_IFREG:
@@ -2131,21 +2310,22 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
                if (fd < 0)
                        return error("open(\"%s\"): %s", path,
                                     strerror(errno));
-               if (index_fd(sha1, fd, st, write_object, NULL) < 0)
+               if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
                        return error("%s: failed to insert into database",
                                     path);
                break;
        case S_IFLNK:
-               target = xmalloc(st->st_size+1);
-               if (readlink(path, target, st->st_size+1) != st->st_size) {
+               len = xsize_t(st->st_size);
+               target = xmalloc(len + 1);
+               if (readlink(path, target, len + 1) != st->st_size) {
                        char *errstr = strerror(errno);
                        free(target);
                        return error("readlink(\"%s\"): %s", path,
                                     errstr);
                }
                if (!write_object)
-                       hash_sha1_file(target, st->st_size, blob_type, sha1);
-               else if (write_sha1_file(target, st->st_size, blob_type, sha1))
+                       hash_sha1_file(target, len, blob_type, sha1);
+               else if (write_sha1_file(target, len, blob_type, sha1))
                        return error("%s: failed to insert into database",
                                     path);
                free(target);