Teach revision walking machinery to walk multiple times sequencially
[gitweb.git] / sha1_file.c
index 32268d11d0c929624729b01f143845b13d7a569c..f9f8d5e91c278000e5869f49ba6a79ddfaf13145 100644 (file)
@@ -18,6 +18,7 @@
 #include "refs.h"
 #include "pack-revindex.h"
 #include "sha1-lookup.h"
+#include "bulk-checkin.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -53,6 +54,8 @@ static struct cached_object empty_tree = {
        0
 };
 
+static struct packed_git *last_found_pack;
+
 static struct cached_object *find_cached_object(const unsigned char *sha1)
 {
        int i;
@@ -248,27 +251,30 @@ static int link_alt_odb_entry(const char * entry, int len, const char * relative
        const char *objdir = get_object_directory();
        struct alternate_object_database *ent;
        struct alternate_object_database *alt;
-       /* 43 = 40-byte + 2 '/' + terminating NUL */
-       int pfxlen = len;
-       int entlen = pfxlen + 43;
-       int base_len = -1;
+       int pfxlen, entlen;
+       struct strbuf pathbuf = STRBUF_INIT;
 
        if (!is_absolute_path(entry) && relative_base) {
-               /* Relative alt-odb */
-               if (base_len < 0)
-                       base_len = strlen(relative_base) + 1;
-               entlen += base_len;
-               pfxlen += base_len;
+               strbuf_addstr(&pathbuf, real_path(relative_base));
+               strbuf_addch(&pathbuf, '/');
        }
-       ent = xmalloc(sizeof(*ent) + entlen);
+       strbuf_add(&pathbuf, entry, len);
 
-       if (!is_absolute_path(entry) && relative_base) {
-               memcpy(ent->base, relative_base, base_len - 1);
-               ent->base[base_len - 1] = '/';
-               memcpy(ent->base + base_len, entry, len);
-       }
-       else
-               memcpy(ent->base, entry, pfxlen);
+       normalize_path_copy(pathbuf.buf, pathbuf.buf);
+
+       pfxlen = strlen(pathbuf.buf);
+
+       /*
+        * The trailing slash after the directory name is given by
+        * this function at the end. Remove duplicates.
+        */
+       while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
+               pfxlen -= 1;
+
+       entlen = pfxlen + 43; /* '/' + 2 hex + '/' + 38 hex + NUL */
+       ent = xmalloc(sizeof(*ent) + entlen);
+       memcpy(ent->base, pathbuf.buf, pfxlen);
+       strbuf_release(&pathbuf);
 
        ent->name = ent->base + pfxlen + 1;
        ent->base[pfxlen + 3] = '/';
@@ -716,6 +722,8 @@ void free_pack_by_name(const char *pack_name)
                        close_pack_index(p);
                        free(p->bad_object_sha1);
                        *pp = p->next;
+                       if (last_found_pack == p)
+                               last_found_pack = NULL;
                        free(p);
                        return;
                }
@@ -1186,7 +1194,7 @@ static int open_sha1_file(const unsigned char *sha1)
        return -1;
 }
 
-static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
        void *map;
        int fd;
@@ -1198,6 +1206,11 @@ static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 
                if (!fstat(fd, &st)) {
                        *size = xsize_t(st.st_size);
+                       if (!*size) {
+                               /* mmap() is forbidden on empty files */
+                               error("object file %s is empty", sha1_file_name(sha1));
+                               return NULL;
+                       }
                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
                }
                close(fd);
@@ -1217,14 +1230,34 @@ static int experimental_loose_object(unsigned char *map)
        unsigned int word;
 
        /*
-        * Is it a zlib-compressed buffer? If so, the first byte
-        * must be 0x78 (15-bit window size, deflated), and the
-        * first 16-bit word is evenly divisible by 31. If so,
-        * we are looking at the official format, not the experimental
-        * one.
+        * We must determine if the buffer contains the standard
+        * zlib-deflated stream or the experimental format based
+        * on the in-pack object format. Compare the header byte
+        * for each format:
+        *
+        * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7
+        * Experimental pack-based : Stttssss : ttt = 1,2,3,4
+        *
+        * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be
+        * in standard loose-object format, UNLESS it is a Git-pack
+        * format object *exactly* 8 bytes in size when inflated.
+        *
+        * However, RFC1950 also specifies that the 1st 16-bit word
+        * must be divisible by 31 - this checksum tells us our buffer
+        * is in the standard format, giving a false positive only if
+        * the 1st word of the Git-pack format object happens to be
+        * divisible by 31, ie:
+        *      ((byte0 * 256) + byte1) % 31 = 0
+        *   =>        0ttt10000www1000 % 31 = 0
+        *
+        * As it happens, this case can only arise for www=3 & ttt=1
+        * - ie, a Commit object, which would have to be 8 bytes in
+        * size. As no Commit can be that small, we find that the
+        * combination of these two criteria (bitmask & checksum)
+        * can always correctly determine the buffer format.
         */
        word = (map[0] << 8) + map[1];
-       if (map[0] == 0x78 && !(word % 31))
+       if ((map[0] & 0x8F) == 0x08 && !(word % 31))
                return 0;
        else
                return 1;
@@ -1244,7 +1277,8 @@ unsigned long unpack_object_header_buffer(const unsigned char *buf,
        while (c & 0x80) {
                if (len <= used || bitsizeof(long) <= shift) {
                        error("bad object header");
-                       return 0;
+                       size = used = 0;
+                       break;
                }
                c = buf[used++];
                size += (c & 0x7f) << shift;
@@ -1254,7 +1288,7 @@ unsigned long unpack_object_header_buffer(const unsigned char *buf,
        return used;
 }
 
-static int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
+int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 {
        unsigned long size, used;
        static const char valid_loose_object_type[8] = {
@@ -1346,7 +1380,7 @@ static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long s
  * too permissive for what we want to check. So do an anal
  * object header parse by hand.
  */
-static int parse_sha1_header(const char *hdr, unsigned long *sizep)
+int parse_sha1_header(const char *hdr, unsigned long *sizep)
 {
        char type[10];
        int i;
@@ -1485,7 +1519,7 @@ static off_t get_delta_base(struct packed_git *p,
 
 /* forward declaration for a mutually recursive function */
 static int packed_object_info(struct packed_git *p, off_t offset,
-                             unsigned long *sizep);
+                             unsigned long *sizep, int *rtype);
 
 static int packed_delta_info(struct packed_git *p,
                             struct pack_window **w_curs,
@@ -1499,7 +1533,7 @@ static int packed_delta_info(struct packed_git *p,
        base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
        if (!base_offset)
                return OBJ_BAD;
-       type = packed_object_info(p, base_offset, NULL);
+       type = packed_object_info(p, base_offset, NULL, NULL);
        if (type <= OBJ_NONE) {
                struct revindex_entry *revidx;
                const unsigned char *base_sha1;
@@ -1527,10 +1561,10 @@ static int packed_delta_info(struct packed_git *p,
        return type;
 }
 
-static int unpack_object_header(struct packed_git *p,
-                               struct pack_window **w_curs,
-                               off_t *curpos,
-                               unsigned long *sizep)
+int unpack_object_header(struct packed_git *p,
+                        struct pack_window **w_curs,
+                        off_t *curpos,
+                        unsigned long *sizep)
 {
        unsigned char *base;
        unsigned long left;
@@ -1553,63 +1587,8 @@ static int unpack_object_header(struct packed_git *p,
        return type;
 }
 
-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;
-       off_t curpos;
-       unsigned long dummy;
-       unsigned char *next_sha1;
-       enum object_type type;
-       struct revindex_entry *revidx;
-
-       *delta_chain_length = 0;
-       curpos = obj_offset;
-       type = unpack_object_header(p, &w_curs, &curpos, size);
-
-       revidx = find_pack_revindex(p, obj_offset);
-       *store_size = revidx[1].offset - obj_offset;
-
-       for (;;) {
-               switch (type) {
-               default:
-                       die("pack %s contains unknown object type %d",
-                           p->pack_name, type);
-               case OBJ_COMMIT:
-               case OBJ_TREE:
-               case OBJ_BLOB:
-               case OBJ_TAG:
-                       unuse_pack(&w_curs);
-                       return typename(type);
-               case OBJ_OFS_DELTA:
-                       obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
-                       if (!obj_offset)
-                               die("pack %s contains bad delta base reference of type %s",
-                                   p->pack_name, typename(type));
-                       if (*delta_chain_length == 0) {
-                               revidx = find_pack_revindex(p, obj_offset);
-                               hashcpy(base_sha1, nth_packed_object_sha1(p, revidx->nr));
-                       }
-                       break;
-               case OBJ_REF_DELTA:
-                       next_sha1 = use_pack(p, &w_curs, curpos, NULL);
-                       if (*delta_chain_length == 0)
-                               hashcpy(base_sha1, next_sha1);
-                       obj_offset = find_pack_entry_one(next_sha1, p);
-                       break;
-               }
-               (*delta_chain_length)++;
-               curpos = obj_offset;
-               type = unpack_object_header(p, &w_curs, &curpos, &dummy);
-       }
-}
-
 static int packed_object_info(struct packed_git *p, off_t obj_offset,
-                             unsigned long *sizep)
+                             unsigned long *sizep, int *rtype)
 {
        struct pack_window *w_curs = NULL;
        unsigned long size;
@@ -1617,6 +1596,8 @@ static int packed_object_info(struct packed_git *p, off_t obj_offset,
        enum object_type type;
 
        type = unpack_object_header(p, &w_curs, &curpos, &size);
+       if (rtype)
+               *rtype = type; /* representation type */
 
        switch (type) {
        case OBJ_OFS_DELTA:
@@ -1699,6 +1680,13 @@ static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
        return hash % MAX_DELTA_CACHE;
 }
 
+static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
+{
+       unsigned long hash = pack_entry_hash(p, base_offset);
+       struct delta_base_cache_entry *ent = delta_base_cache + hash;
+       return (ent->data && ent->p == p && ent->base_offset == base_offset);
+}
+
 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)
 {
@@ -1843,6 +1831,24 @@ static void *unpack_delta_entry(struct packed_git *p,
        return result;
 }
 
+static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
+{
+       static FILE *log_file;
+
+       if (!log_file) {
+               log_file = fopen(log_pack_access, "w");
+               if (!log_file) {
+                       error("cannot open pack access log '%s' for writing: %s",
+                             log_pack_access, strerror(errno));
+                       log_pack_access = NULL;
+                       return;
+               }
+       }
+       fprintf(log_file, "%s %"PRIuMAX"\n",
+               p->pack_name, (uintmax_t)obj_offset);
+       fflush(log_file);
+}
+
 int do_check_packed_object_crc;
 
 void *unpack_entry(struct packed_git *p, off_t obj_offset,
@@ -1852,6 +1858,9 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
        off_t curpos = obj_offset;
        void *data;
 
+       if (log_pack_access)
+               write_pack_access_log(p, obj_offset);
+
        if (do_check_packed_object_crc && p->index_version > 1) {
                struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
                unsigned long len = revidx[1].offset - obj_offset;
@@ -1989,7 +1998,7 @@ off_t find_pack_entry_one(const unsigned char *sha1,
        return 0;
 }
 
-static int is_pack_valid(struct packed_git *p)
+int is_pack_valid(struct packed_git *p)
 {
        /* An already open pack is known to be valid. */
        if (p->pack_fd != -1)
@@ -2010,54 +2019,58 @@ static int is_pack_valid(struct packed_git *p)
        return !open_packed_git(p);
 }
 
+static int fill_pack_entry(const unsigned char *sha1,
+                          struct pack_entry *e,
+                          struct packed_git *p)
+{
+       off_t offset;
+
+       if (p->num_bad_objects) {
+               unsigned i;
+               for (i = 0; i < p->num_bad_objects; i++)
+                       if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+                               return 0;
+       }
+
+       offset = find_pack_entry_one(sha1, p);
+       if (!offset)
+               return 0;
+
+       /*
+        * We are about to tell the caller where they can locate the
+        * requested object.  We better make sure the packfile is
+        * still here and can be accessed before supplying that
+        * answer, as it may have been deleted since the index was
+        * loaded!
+        */
+       if (!is_pack_valid(p)) {
+               warning("packfile %s cannot be accessed", p->pack_name);
+               return 0;
+       }
+       e->offset = offset;
+       e->p = p;
+       hashcpy(e->sha1, sha1);
+       return 1;
+}
+
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 {
-       static struct packed_git *last_found = (void *)1;
        struct packed_git *p;
-       off_t offset;
 
        prepare_packed_git();
        if (!packed_git)
                return 0;
-       p = (last_found == (void *)1) ? packed_git : last_found;
 
-       do {
-               if (p->num_bad_objects) {
-                       unsigned i;
-                       for (i = 0; i < p->num_bad_objects; i++)
-                               if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
-                                       goto next;
-               }
+       if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack))
+               return 1;
 
-               offset = find_pack_entry_one(sha1, p);
-               if (offset) {
-                       /*
-                        * We are about to tell the caller where they can
-                        * locate the requested object.  We better make
-                        * sure the packfile is still here and can be
-                        * accessed before supplying that answer, as
-                        * it may have been deleted since the index
-                        * was loaded!
-                        */
-                       if (!is_pack_valid(p)) {
-                               error("packfile %s cannot be accessed", p->pack_name);
-                               goto next;
-                       }
-                       e->offset = offset;
-                       e->p = p;
-                       hashcpy(e->sha1, sha1);
-                       last_found = p;
-                       return 1;
-               }
+       for (p = packed_git; p; p = p->next) {
+               if (p == last_found_pack || !fill_pack_entry(sha1, e, p))
+                       continue;
 
-               next:
-               if (p == last_found)
-                       p = packed_git;
-               else
-                       p = p->next;
-               if (p == last_found)
-                       p = p->next;
-       } while (p);
+               last_found_pack = p;
+               return 1;
+       }
        return 0;
 }
 
@@ -2097,24 +2110,28 @@ static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *size
        return status;
 }
 
-int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
+/* returns enum object_type or negative */
+int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
 {
        struct cached_object *co;
        struct pack_entry e;
-       int status;
+       int status, rtype;
 
        co = find_cached_object(sha1);
        if (co) {
-               if (sizep)
-                       *sizep = co->size;
+               if (oi->sizep)
+                       *(oi->sizep) = co->size;
+               oi->whence = OI_CACHED;
                return co->type;
        }
 
        if (!find_pack_entry(sha1, &e)) {
                /* Most likely it's a loose object. */
-               status = sha1_loose_object_info(sha1, sizep);
-               if (status >= 0)
+               status = sha1_loose_object_info(sha1, oi->sizep);
+               if (status >= 0) {
+                       oi->whence = OI_LOOSE;
                        return status;
+               }
 
                /* Not a loose object; someone else may have just packed it. */
                reprepare_packed_git();
@@ -2122,15 +2139,31 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
                        return status;
        }
 
-       status = packed_object_info(e.p, e.offset, sizep);
+       status = packed_object_info(e.p, e.offset, oi->sizep, &rtype);
        if (status < 0) {
                mark_bad_packed_object(e.p, sha1);
-               status = sha1_object_info(sha1, sizep);
+               status = sha1_object_info_extended(sha1, oi);
+       } else if (in_delta_base_cache(e.p, e.offset)) {
+               oi->whence = OI_DBCACHED;
+       } else {
+               oi->whence = OI_PACKED;
+               oi->u.packed.offset = e.offset;
+               oi->u.packed.pack = e.p;
+               oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
+                                        rtype == OBJ_OFS_DELTA);
        }
 
        return status;
 }
 
+int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
+{
+       struct object_info oi;
+
+       oi.sizep = sizep;
+       return sha1_object_info_extended(sha1, &oi);
+}
+
 static void *read_packed_sha1(const unsigned char *sha1,
                              enum object_type *type, unsigned long *size)
 {
@@ -2432,15 +2465,15 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
        git_SHA_CTX c;
        unsigned char parano_sha1[20];
        char *filename;
-       static char tmpfile[PATH_MAX];
+       static char tmp_file[PATH_MAX];
 
        filename = sha1_file_name(sha1);
-       fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
+       fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
        if (fd < 0) {
                if (errno == EACCES)
                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
                else
-                       return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
+                       return error("unable to create temporary sha1 filename %s: %s\n", tmp_file, strerror(errno));
        }
 
        /* Set it up */
@@ -2485,12 +2518,12 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
                struct utimbuf utb;
                utb.actime = mtime;
                utb.modtime = mtime;
-               if (utime(tmpfile, &utb) < 0)
+               if (utime(tmp_file, &utb) < 0)
                        warning("failed utime() on %s: %s",
-                               tmpfile, strerror(errno));
+                               tmp_file, strerror(errno));
        }
 
-       return move_temp_to_file(tmpfile, filename);
+       return move_temp_to_file(tmp_file, filename);
 }
 
 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
@@ -2598,7 +2631,7 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
        if ((type == OBJ_BLOB) && path) {
                struct strbuf nbuf = STRBUF_INIT;
                if (convert_to_git(path, buf, size, &nbuf,
-                                  write_object ? safe_crlf : 0)) {
+                                  write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
                        buf = strbuf_detach(&nbuf, &size);
                        re_allocated = 1;
                }
@@ -2661,10 +2694,8 @@ static int index_core(unsigned char *sha1, int fd, size_t size,
 }
 
 /*
- * This creates one packfile per large blob, because the caller
- * immediately wants the result sha1, and fast-import can report the
- * object name via marks mechanism only by closing the created
- * packfile.
+ * This creates one packfile per large blob unless bulk-checkin
+ * machinery is "plugged".
  *
  * This also bypasses the usual "convert-to-git" dance, and that is on
  * purpose. We could write a streaming version of the converting
@@ -2678,65 +2709,7 @@ static int index_stream(unsigned char *sha1, int fd, size_t size,
                        enum object_type type, const char *path,
                        unsigned flags)
 {
-       struct child_process fast_import;
-       char export_marks[512];
-       const char *argv[] = { "fast-import", "--quiet", export_marks, NULL };
-       char tmpfile[512];
-       char fast_import_cmd[512];
-       char buf[512];
-       int len, tmpfd;
-
-       strcpy(tmpfile, git_path("hashstream_XXXXXX"));
-       tmpfd = git_mkstemp_mode(tmpfile, 0600);
-       if (tmpfd < 0)
-               die_errno("cannot create tempfile: %s", tmpfile);
-       if (close(tmpfd))
-               die_errno("cannot close tempfile: %s", tmpfile);
-       sprintf(export_marks, "--export-marks=%s", tmpfile);
-
-       memset(&fast_import, 0, sizeof(fast_import));
-       fast_import.in = -1;
-       fast_import.argv = argv;
-       fast_import.git_cmd = 1;
-       if (start_command(&fast_import))
-               die_errno("index-stream: git fast-import failed");
-
-       len = sprintf(fast_import_cmd, "blob\nmark :1\ndata %lu\n",
-                     (unsigned long) size);
-       write_or_whine(fast_import.in, fast_import_cmd, len,
-                      "index-stream: feeding fast-import");
-       while (size) {
-               char buf[10240];
-               size_t sz = size < sizeof(buf) ? size : sizeof(buf);
-               size_t actual;
-
-               actual = read_in_full(fd, buf, sz);
-               if (actual < 0)
-                       die_errno("index-stream: reading input");
-               if (write_in_full(fast_import.in, buf, actual) != actual)
-                       die_errno("index-stream: feeding fast-import");
-               size -= actual;
-       }
-       if (close(fast_import.in))
-               die_errno("index-stream: closing fast-import");
-       if (finish_command(&fast_import))
-               die_errno("index-stream: finishing fast-import");
-
-       tmpfd = open(tmpfile, O_RDONLY);
-       if (tmpfd < 0)
-               die_errno("index-stream: cannot open fast-import mark");
-       len = read(tmpfd, buf, sizeof(buf));
-       if (len < 0)
-               die_errno("index-stream: reading fast-import mark");
-       if (close(tmpfd) < 0)
-               die_errno("index-stream: closing fast-import mark");
-       if (unlink(tmpfile))
-               die_errno("index-stream: unlinking fast-import mark");
-       if (len != 44 ||
-           memcmp(":1 ", buf, 3) ||
-           get_sha1_hex(buf + 3, sha1))
-               die_errno("index-stream: unexpected fast-import mark: <%s>", buf);
-       return 0;
+       return index_bulk_checkin(sha1, fd, size, type, path, flags);
 }
 
 int index_fd(unsigned char *sha1, int fd, struct stat *st,