Documentation(cvs-migration): minor cleanups.
[gitweb.git] / sha1_file.c
index e9285c144e05b4b3528c7a96025730dd9a7b3668..111a71de6b3bb33b7e2ca1879613a70bc3a6ed81 100644 (file)
@@ -20,6 +20,8 @@
 #endif
 #endif
 
+const unsigned char null_sha1[20] = { 0, };
+
 static unsigned int sha1_file_open_flag = O_NOATIME;
 
 static unsigned hexval(char c)
@@ -46,61 +48,11 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
        return 0;
 }
 
-static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
-       *git_graft_file;
-static void setup_git_env(void)
-{
-       git_dir = gitenv(GIT_DIR_ENVIRONMENT);
-       if (!git_dir)
-               git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
-       git_object_dir = gitenv(DB_ENVIRONMENT);
-       if (!git_object_dir) {
-               git_object_dir = xmalloc(strlen(git_dir) + 9);
-               sprintf(git_object_dir, "%s/objects", git_dir);
-       }
-       git_refs_dir = xmalloc(strlen(git_dir) + 6);
-       sprintf(git_refs_dir, "%s/refs", git_dir);
-       git_index_file = gitenv(INDEX_ENVIRONMENT);
-       if (!git_index_file) {
-               git_index_file = xmalloc(strlen(git_dir) + 7);
-               sprintf(git_index_file, "%s/index", git_dir);
-       }
-       git_graft_file = gitenv(GRAFT_ENVIRONMENT);
-       if (!git_graft_file)
-               git_graft_file = strdup(git_path("info/grafts"));
-}
-
-char *get_object_directory(void)
-{
-       if (!git_object_dir)
-               setup_git_env();
-       return git_object_dir;
-}
-
-char *get_refs_directory(void)
-{
-       if (!git_refs_dir)
-               setup_git_env();
-       return git_refs_dir;
-}
-
-char *get_index_file(void)
-{
-       if (!git_index_file)
-               setup_git_env();
-       return git_index_file;
-}
-
-char *get_graft_file(void)
-{
-       if (!git_graft_file)
-               setup_git_env();
-       return git_graft_file;
-}
-
 int safe_create_leading_directories(char *path)
 {
        char *pos = path;
+       if (*pos == '/')
+               pos++;
 
        while (pos) {
                pos = strchr(pos, '/');
@@ -222,84 +174,139 @@ char *sha1_pack_index_name(const unsigned char *sha1)
        return base;
 }
 
-struct alternate_object_database *alt_odb;
+struct alternate_object_database *alt_odb_list;
+static struct alternate_object_database **alt_odb_tail;
 
 /*
  * Prepare alternate object database registry.
- * alt_odb points at an array of struct alternate_object_database.
- * This array is terminated with an element that has both its base
- * and name set to NULL.  alt_odb[n] comes from n'th non-empty
- * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
- * variable, and its base points at a statically allocated buffer
- * that contains "/the/directory/corresponding/to/.git/objects/...",
- * while its name points just after the slash at the end of
- * ".git/objects/" in the example above, and has enough space to hold
- * 40-byte hex SHA1, an extra slash for the first level indirection,
- * and the terminating NUL.
- * This function allocates the alt_odb array and all the strings
- * pointed by base fields of the array elements with one xmalloc();
- * the string pool immediately follows the array.
+ *
+ * The variable alt_odb_list points at the list of struct
+ * alternate_object_database.  The elements on this list come from
+ * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
+ * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
+ * whose contents is similar to that environment variable but can be
+ * LF separated.  Its base points at a statically allocated buffer that
+ * contains "/the/directory/corresponding/to/.git/objects/...", while
+ * its name points just after the slash at the end of ".git/objects/"
+ * in the example above, and has enough space to hold 40-byte hex
+ * SHA1, an extra slash for the first level indirection, and the
+ * terminating NUL.
  */
-void prepare_alt_odb(void)
+static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
+                                const char *relative_base)
 {
-       int pass, totlen, i;
        const char *cp, *last;
-       char *op = NULL;
-       const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
+       struct alternate_object_database *ent;
+       const char *objdir = get_object_directory();
+       int base_len = -1;
+
+       last = alt;
+       while (last < ep) {
+               cp = last;
+               if (cp < ep && *cp == '#') {
+                       while (cp < ep && *cp != sep)
+                               cp++;
+                       last = cp + 1;
+                       continue;
+               }
+               for ( ; cp < ep && *cp != sep; cp++)
+                       ;
+               if (last != cp) {
+                       struct alternate_object_database *alt;
+                       /* 43 = 40-byte + 2 '/' + terminating NUL */
+                       int pfxlen = cp - last;
+                       int entlen = pfxlen + 43;
+
+                       if (*last != '/' && relative_base) {
+                               /* Relative alt-odb */
+                               if (base_len < 0)
+                                       base_len = strlen(relative_base) + 1;
+                               entlen += base_len;
+                               pfxlen += base_len;
+                       }
+                       ent = xmalloc(sizeof(*ent) + entlen);
 
-       if (alt_odb)
-               return;
-       /* The first pass counts how large an area to allocate to
-        * hold the entire alt_odb structure, including array of
-        * structs and path buffers for them.  The second pass fills
-        * the structure and prepares the path buffers for use by
-        * fill_sha1_path().
-        */
-       for (totlen = pass = 0; pass < 2; pass++) {
-               last = alt;
-               i = 0;
-               do {
-                       cp = strchr(last, ':') ? : last + strlen(last);
-                       if (last != cp) {
-                               /* 43 = 40-byte + 2 '/' + terminating NUL */
-                               int pfxlen = cp - last;
-                               int entlen = pfxlen + 43;
-                               if (pass == 0)
-                                       totlen += entlen;
-                               else {
-                                       alt_odb[i].base = op;
-                                       alt_odb[i].name = op + pfxlen + 1;
-                                       memcpy(op, last, pfxlen);
-                                       op[pfxlen] = op[pfxlen + 3] = '/';
-                                       op[entlen-1] = 0;
-                                       op += entlen;
-                               }
-                               i++;
+                       if (*last != '/' && relative_base) {
+                               memcpy(ent->base, relative_base, base_len - 1);
+                               ent->base[base_len - 1] = '/';
+                               memcpy(ent->base + base_len,
+                                      last, cp - last);
                        }
-                       while (*cp && *cp == ':')
-                               cp++;
-                       last = cp;
-               } while (*cp);
-               if (pass)
-                       break;
-               alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
-               alt_odb[i].base = alt_odb[i].name = NULL;
-               op = (char*)(&alt_odb[i+1]);
+                       else
+                               memcpy(ent->base, last, pfxlen);
+                       ent->name = ent->base + pfxlen + 1;
+                       ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
+                       ent->base[entlen-1] = 0;
+
+                       /* Prevent the common mistake of listing the same
+                        * thing twice, or object directory itself.
+                        */
+                       for (alt = alt_odb_list; alt; alt = alt->next)
+                               if (!memcmp(ent->base, alt->base, pfxlen))
+                                       goto bad;
+                       if (!memcmp(ent->base, objdir, pfxlen)) {
+                       bad:
+                               free(ent);
+                       }
+                       else {
+                               *alt_odb_tail = ent;
+                               alt_odb_tail = &(ent->next);
+                               ent->next = NULL;
+                       }
+               }
+               while (cp < ep && *cp == sep)
+                       cp++;
+               last = cp;
+       }
+}
+
+void prepare_alt_odb(void)
+{
+       char path[PATH_MAX];
+       char *map;
+       int fd;
+       struct stat st;
+       char *alt;
+
+       alt = getenv(ALTERNATE_DB_ENVIRONMENT);
+       if (!alt) alt = "";
+
+       if (alt_odb_tail)
+               return;
+       alt_odb_tail = &alt_odb_list;
+       link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
+
+       sprintf(path, "%s/info/alternates", get_object_directory());
+       fd = open(path, O_RDONLY);
+       if (fd < 0)
+               return;
+       if (fstat(fd, &st) || (st.st_size == 0)) {
+               close(fd);
+               return;
        }
+       map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       close(fd);
+       if (map == MAP_FAILED)
+               return;
+
+       link_alt_odb_entries(map, map + st.st_size, '\n',
+                            get_object_directory());
+       munmap(map, st.st_size);
 }
 
 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 {
-       int i;
        char *name = sha1_file_name(sha1);
+       struct alternate_object_database *alt;
 
        if (!stat(name, st))
                return name;
        prepare_alt_odb();
-       for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
+       for (alt = alt_odb_list; alt; alt = alt->next) {
+               name = alt->name;
                fill_sha1_path(name, sha1);
-               if (!stat(alt_odb[i].base, st))
-                       return alt_odb[i].base;
+               if (!stat(alt->base, st))
+                       return alt->base;
        }
        return NULL;
 }
@@ -427,12 +434,13 @@ int use_packed_git(struct packed_git *p)
        return 0;
 }
 
-struct packed_git *add_packed_git(char *path, int path_len)
+struct packed_git *add_packed_git(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];
 
        if (check_packed_git_idx(path, &idx_size, &idx_map))
                return NULL;
@@ -455,17 +463,26 @@ struct packed_git *add_packed_git(char *path, int path_len)
        p->pack_base = NULL;
        p->pack_last_used = 0;
        p->pack_use_cnt = 0;
+       p->pack_local = local;
+       if (!get_sha1_hex(path + path_len - 40 - 4, sha1))
+               memcpy(p->sha1, sha1, 20);
        return p;
 }
 
 struct packed_git *parse_pack_index(unsigned char *sha1)
+{
+       char *path = sha1_pack_index_name(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 *p;
        unsigned long idx_size;
        void *idx_map;
-       char *path = sha1_pack_index_name(sha1);
+       char *path;
 
-       if (check_packed_git_idx(path, &idx_size, &idx_map))
+       if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
                return NULL;
 
        path = sha1_pack_name(sha1);
@@ -489,7 +506,7 @@ void install_packed_git(struct packed_git *pack)
        packed_git = pack;
 }
 
-static void prepare_packed_git_one(char *objdir)
+static void prepare_packed_git_one(char *objdir, int local)
 {
        char path[PATH_MAX];
        int len;
@@ -511,7 +528,7 @@ static void prepare_packed_git_one(char *objdir)
 
                /* we have .idx.  Is it a file we can map? */
                strcpy(path + len, de->d_name);
-               p = add_packed_git(path, len + namelen);
+               p = add_packed_git(path, len + namelen, local);
                if (!p)
                        continue;
                p->next = packed_git;
@@ -522,18 +539,19 @@ static void prepare_packed_git_one(char *objdir)
 
 void prepare_packed_git(void)
 {
-       int i;
        static int run_once = 0;
+       struct alternate_object_database *alt;
 
-       if (run_once++)
+       if (run_once)
                return;
-
-       prepare_packed_git_one(get_object_directory());
+       prepare_packed_git_one(get_object_directory(), 1);
        prepare_alt_odb();
-       for (i = 0; alt_odb[i].base != NULL; i++) {
-               alt_odb[i].name[0] = 0;
-               prepare_packed_git_one(alt_odb[i].base);
+       for (alt = alt_odb_list; alt; alt = alt->next) {
+               alt->name[-1] = 0;
+               prepare_packed_git_one(alt->base, 0);
+               alt->name[-1] = '/';
        }
+       run_once = 1;
 }
 
 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
@@ -819,7 +837,8 @@ void packed_object_info_detail(struct pack_entry *e,
                strcpy(type, "tag");
                break;
        default:
-               die("corrupted pack file");
+               die("corrupted pack file %s containing object of kind %d",
+                   p->pack_name, kind);
        }
        *store_size = 0; /* notyet */
 }
@@ -858,7 +877,8 @@ static int packed_object_info(struct pack_entry *entry,
                strcpy(type, "tag");
                break;
        default:
-               die("corrupted pack file");
+               die("corrupted pack file %s containing object of kind %d",
+                   p->pack_name, kind);
        }
        if (sizep)
                *sizep = size;
@@ -958,7 +978,7 @@ static void *unpack_entry(struct pack_entry *entry,
        retval = unpack_entry_gently(entry, type, sizep);
        unuse_packed_git(p);
        if (!retval)
-               die("corrupted pack file");
+               die("corrupted pack file %s", p->pack_name);
        return retval;
 }
 
@@ -1192,6 +1212,77 @@ char *write_sha1_file_prepare(void *buf,
        return sha1_file_name(sha1);
 }
 
+/*
+ * Link the tempfile to the final place, possibly creating the
+ * last directory level as you do so.
+ *
+ * Returns the errno on failure, 0 on success.
+ */
+static int link_temp_to_file(const char *tmpfile, char *filename)
+{
+       int ret;
+
+       if (!link(tmpfile, filename))
+               return 0;
+
+       /*
+        * Try to mkdir the last path component if that failed
+        * with an ENOENT.
+        *
+        * Re-try the "link()" regardless of whether the mkdir
+        * succeeds, since a race might mean that somebody
+        * else succeeded.
+        */
+       ret = errno;
+       if (ret == ENOENT) {
+               char *dir = strrchr(filename, '/');
+               if (dir) {
+                       *dir = 0;
+                       mkdir(filename, 0777);
+                       *dir = '/';
+                       if (!link(tmpfile, filename))
+                               return 0;
+                       ret = errno;
+               }
+       }
+       return ret;
+}
+
+/*
+ * Move the just written object into its final resting place
+ */
+int move_temp_to_file(const char *tmpfile, char *filename)
+{
+       int ret = link_temp_to_file(tmpfile, filename);
+
+       /*
+        * Coda hack - coda doesn't like cross-directory links,
+        * so we fall back to a rename, which will mean that it
+        * won't be able to check collisions, but that's not a
+        * big deal.
+        *
+        * The same holds for FAT formatted media.
+        *
+        * When this succeeds, we just return 0. We have nothing
+        * left to unlink.
+        */
+       if (ret && ret != EEXIST) {
+               if (!rename(tmpfile, filename))
+                       return 0;
+               ret = errno;
+       }
+       unlink(tmpfile);
+       if (ret) {
+               if (ret != EEXIST) {
+                       fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
+                       return -1;
+               }
+               /* FIXME!!! Collision check here ? */
+       }
+
+       return 0;
+}
+
 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
        int size;
@@ -1201,7 +1292,7 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
        char *filename;
        static char tmpfile[PATH_MAX];
        unsigned char hdr[50];
-       int fd, hdrlen, ret;
+       int fd, hdrlen;
 
        /* Normally if we have it in the pack then we do not bother writing
         * it out into .git/objects/??/?{38} file.
@@ -1264,32 +1355,7 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
        close(fd);
        free(compressed);
 
-       ret = link(tmpfile, filename);
-       if (ret < 0) {
-               ret = errno;
-
-               /*
-                * Coda hack - coda doesn't like cross-directory links,
-                * so we fall back to a rename, which will mean that it
-                * won't be able to check collisions, but that's not a
-                * big deal.
-                *
-                * When this succeeds, we just return 0. We have nothing
-                * left to unlink.
-                */
-               if (ret == EXDEV && !rename(tmpfile, filename))
-                       return 0;
-       }
-       unlink(tmpfile);
-       if (ret) {
-               if (ret != EEXIST) {
-                       fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
-                       return -1;
-               }
-               /* FIXME!!! Collision check here ? */
-       }
-
-       return 0;
+       return move_temp_to_file(tmpfile, filename);
 }
 
 int write_sha1_to_fd(int fd, const unsigned char *sha1)
@@ -1364,8 +1430,7 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
                       size_t bufsize, size_t *bufposn)
 {
-       char *filename = sha1_file_name(sha1);
-
+       char tmpfile[PATH_MAX];
        int local;
        z_stream stream;
        unsigned char real_sha1[20];
@@ -1373,10 +1438,11 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
        int ret;
        SHA_CTX c;
 
-       local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+       snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
 
+       local = mkstemp(tmpfile);
        if (local < 0)
-               return error("Couldn't open %s\n", filename);
+               return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
 
        memset(&stream, 0, sizeof(stream));
 
@@ -1388,7 +1454,7 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
                ssize_t size;
                if (*bufposn) {
                        stream.avail_in = *bufposn;
-                       stream.next_in = buffer;
+                       stream.next_in = (unsigned char *) buffer;
                        do {
                                stream.next_out = discard;
                                stream.avail_out = sizeof(discard);
@@ -1406,7 +1472,7 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
                size = read(fd, buffer + *bufposn, bufsize - *bufposn);
                if (size <= 0) {
                        close(local);
-                       unlink(filename);
+                       unlink(tmpfile);
                        if (!size)
                                return error("Connection closed?");
                        perror("Reading from connection");
@@ -1419,15 +1485,15 @@ int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
        close(local);
        SHA1_Final(real_sha1, &c);
        if (ret != Z_STREAM_END) {
-               unlink(filename);
+               unlink(tmpfile);
                return error("File %s corrupted", sha1_to_hex(sha1));
        }
        if (memcmp(sha1, real_sha1, 20)) {
-               unlink(filename);
+               unlink(tmpfile);
                return error("File %s has bad hash\n", sha1_to_hex(sha1));
        }
-       
-       return 0;
+
+       return move_temp_to_file(tmpfile, sha1_file_name(sha1));
 }
 
 int has_pack_index(const unsigned char *sha1)
@@ -1489,3 +1555,42 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
                munmap(buf, size);
        return ret;
 }
+
+int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
+{
+       int fd;
+       char *target;
+
+       switch (st->st_mode & S_IFMT) {
+       case S_IFREG:
+               fd = open(path, O_RDONLY);
+               if (fd < 0)
+                       return error("open(\"%s\"): %s", path,
+                                    strerror(errno));
+               if (index_fd(sha1, fd, st, write_object, NULL) < 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) {
+                       char *errstr = strerror(errno);
+                       free(target);
+                       return error("readlink(\"%s\"): %s", path,
+                                    errstr);
+               }
+               if (!write_object) {
+                       unsigned char hdr[50];
+                       int hdrlen;
+                       write_sha1_file_prepare(target, st->st_size, "blob",
+                                               sha1, hdr, &hdrlen);
+               } else if (write_sha1_file(target, st->st_size, "blob", sha1))
+                       return error("%s: failed to insert into database",
+                                    path);
+               free(target);
+               break;
+       default:
+               return error("%s: unsupported file type", path);
+       }
+       return 0;
+}