Move pack_refs() and friends into libgit
[gitweb.git] / sha1_file.c
index 3516777bc7614c23da02dd7a9aa28a48294d56cb..191f814e09ee6067edf7b0acc73a04751e73a6da 100644 (file)
@@ -35,8 +35,6 @@ static size_t sz_fmt(size_t s) { return s; }
 
 const unsigned char null_sha1[20];
 
-static unsigned int sha1_file_open_flag = O_NOATIME;
-
 const signed char hexval_table[256] = {
         -1, -1, -1, -1, -1, -1, -1, -1,                /* 00-07 */
         -1, -1, -1, -1, -1, -1, -1, -1,                /* 08-0f */
@@ -118,7 +116,7 @@ int safe_create_leading_directories(char *path)
        return 0;
 }
 
-char * sha1_to_hex(const unsigned char *sha1)
+char *sha1_to_hex(const unsigned char *sha1)
 {
        static int bufno;
        static char hexbuffer[4][50];
@@ -176,21 +174,23 @@ char *sha1_file_name(const unsigned char *sha1)
        return base;
 }
 
-char *sha1_pack_name(const unsigned char *sha1)
+static char *sha1_get_pack_name(const unsigned char *sha1,
+                               char **name, char **base, const char *which)
 {
        static const char hex[] = "0123456789abcdef";
-       static char *name, *base, *buf;
+       char *buf;
        int i;
 
-       if (!base) {
+       if (!*base) {
                const char *sha1_file_directory = get_object_directory();
                int len = strlen(sha1_file_directory);
-               base = xmalloc(len + 60);
-               sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
-               name = base + len + 11;
+               *base = xmalloc(len + 60);
+               sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
+                       sha1_file_directory, which);
+               *name = *base + len + 11;
        }
 
-       buf = name;
+       buf = *name;
 
        for (i = 0; i < 20; i++) {
                unsigned int val = *sha1++;
@@ -198,32 +198,21 @@ char *sha1_pack_name(const unsigned char *sha1)
                *buf++ = hex[val & 0xf];
        }
 
-       return base;
+       return *base;
 }
 
-char *sha1_pack_index_name(const unsigned char *sha1)
+char *sha1_pack_name(const unsigned char *sha1)
 {
-       static const char hex[] = "0123456789abcdef";
-       static char *name, *base, *buf;
-       int i;
-
-       if (!base) {
-               const char *sha1_file_directory = get_object_directory();
-               int len = strlen(sha1_file_directory);
-               base = xmalloc(len + 60);
-               sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
-               name = base + len + 11;
-       }
+       static char *name, *base;
 
-       buf = name;
+       return sha1_get_pack_name(sha1, &name, &base, "pack");
+}
 
-       for (i = 0; i < 20; i++) {
-               unsigned int val = *sha1++;
-               *buf++ = hex[val >> 4];
-               *buf++ = hex[val & 0xf];
-       }
+char *sha1_pack_index_name(const unsigned char *sha1)
+{
+       static char *name, *base;
 
-       return base;
+       return sha1_get_pack_name(sha1, &name, &base, "idx");
 }
 
 struct alternate_object_database *alt_odb_list;
@@ -380,6 +369,18 @@ static void read_info_alternates(const char * relative_base, int depth)
        munmap(map, mapsz);
 }
 
+void add_to_alternates_file(const char *reference)
+{
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), 1);
+       char *alt = mkpath("%s/objects\n", reference);
+       write_or_die(fd, alt, strlen(alt));
+       if (commit_lock_file(lock))
+               die("could not close alternates file");
+       if (alt_odb_tail)
+               link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
+}
+
 void prepare_alt_odb(void)
 {
        const char *alt;
@@ -396,21 +397,21 @@ void prepare_alt_odb(void)
        read_info_alternates(get_object_directory(), 0);
 }
 
-static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
+static int has_loose_object(const unsigned char *sha1)
 {
        char *name = sha1_file_name(sha1);
        struct alternate_object_database *alt;
 
-       if (!stat(name, st))
-               return name;
+       if (!access(name, F_OK))
+               return 1;
        prepare_alt_odb();
        for (alt = alt_odb_list; alt; alt = alt->next) {
                name = alt->name;
                fill_sha1_path(name, sha1);
-               if (!stat(alt->base, st))
-                       return alt->base;
+               if (!access(alt->base, F_OK))
+                       return 1;
        }
-       return NULL;
+       return 0;
 }
 
 static unsigned int pack_used_ctr;
@@ -830,13 +831,7 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 
 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,
-                                        const char *idx_path)
-{
+       const char *idx_path = sha1_pack_index_name(sha1);
        const char *path = sha1_pack_name(sha1);
        struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
 
@@ -994,38 +989,58 @@ int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long siz
        return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
+static int git_open_noatime(const char *name)
+{
+       static int sha1_file_open_flag = O_NOATIME;
+       int fd = open(name, O_RDONLY | sha1_file_open_flag);
+
+       /* Might the failure be due to O_NOATIME? */
+       if (fd < 0 && errno != ENOENT && sha1_file_open_flag) {
+               fd = open(name, O_RDONLY);
+               if (fd >= 0)
+                       sha1_file_open_flag = 0;
+       }
+       return fd;
+}
+
+static int open_sha1_file(const unsigned char *sha1)
+{
+       int fd;
+       char *name = sha1_file_name(sha1);
+       struct alternate_object_database *alt;
+
+       fd = git_open_noatime(name);
+       if (fd >= 0)
+               return fd;
+
+       prepare_alt_odb();
+       errno = ENOENT;
+       for (alt = alt_odb_list; alt; alt = alt->next) {
+               name = alt->name;
+               fill_sha1_path(name, sha1);
+               fd = git_open_noatime(alt->base);
+               if (fd >= 0)
+                       return fd;
+       }
+       return -1;
+}
+
 static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
-       struct stat st;
        void *map;
        int fd;
-       char *filename = find_sha1_file(sha1, &st);
 
-       if (!filename) {
-               return NULL;
-       }
+       fd = open_sha1_file(sha1);
+       map = NULL;
+       if (fd >= 0) {
+               struct stat st;
 
-       fd = open(filename, O_RDONLY | sha1_file_open_flag);
-       if (fd < 0) {
-               /* See if it works without O_NOATIME */
-               switch (sha1_file_open_flag) {
-               default:
-                       fd = open(filename, O_RDONLY);
-                       if (fd >= 0)
-                               break;
-               /* Fallthrough */
-               case 0:
-                       return NULL;
+               if (!fstat(fd, &st)) {
+                       *size = xsize_t(st.st_size);
+                       map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
                }
-
-               /* If it failed once, it will probably fail again.
-                * Stop using O_NOATIME
-                */
-               sha1_file_open_flag = 0;
+               close(fd);
        }
-       *size = xsize_t(st.st_size);
-       map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
-       close(fd);
        return map;
 }
 
@@ -2015,49 +2030,12 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
        SHA1_Final(sha1, &c);
 }
 
-/*
- * 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, const char *filename)
-{
-       int ret;
-       char *dir;
-
-       if (!link(tmpfile, filename))
-               return 0;
-
-       /*
-        * Try to mkdir the last path component if that failed.
-        *
-        * Re-try the "link()" regardless of whether the mkdir
-        * succeeds, since a race might mean that somebody
-        * else succeeded.
-        */
-       ret = errno;
-       dir = strrchr(filename, '/');
-       if (dir) {
-               *dir = 0;
-               if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
-                       *dir = '/';
-                       return -2;
-               }
-               *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, const char *filename)
 {
-       int ret = link_temp_to_file(tmpfile, filename);
+       int ret = link(tmpfile, filename);
 
        /*
         * Coda hack - coda doesn't like cross-directory links,
@@ -2102,43 +2080,66 @@ int hash_sha1_file(const void *buf, unsigned long len, const char *type,
        return 0;
 }
 
-int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
+/* Finalize a file on disk, and close it. */
+static void close_sha1_file(int fd)
 {
-       int size, ret;
-       unsigned char *compressed;
-       z_stream stream;
-       unsigned char sha1[20];
-       char *filename;
-       static char tmpfile[PATH_MAX];
-       char hdr[32];
-       int fd, hdrlen;
+       /* For safe-mode, we could fsync_or_die(fd, "sha1 file") here */
+       fchmod(fd, 0444);
+       if (close(fd) != 0)
+               die("unable to write sha1 file");
+}
 
-       /* Normally if we have it in the pack then we do not bother writing
-        * it out into .git/objects/??/?{38} file.
-        */
-       write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
-       filename = sha1_file_name(sha1);
-       if (returnsha1)
-               hashcpy(returnsha1, sha1);
-       if (has_sha1_file(sha1))
-               return 0;
-       fd = open(filename, O_RDONLY);
-       if (fd >= 0) {
-               /*
-                * FIXME!!! We might do collision checking here, but we'd
-                * need to uncompress the old file and check it. Later.
-                */
-               close(fd);
+/* Size of directory component, including the ending '/' */
+static inline int directory_size(const char *filename)
+{
+       const char *s = strrchr(filename, '/');
+       if (!s)
                return 0;
+       return s - filename + 1;
+}
+
+/*
+ * This creates a temporary file in the same directory as the final
+ * 'filename'
+ *
+ * We want to avoid cross-directory filename renames, because those
+ * can have problems on various filesystems (FAT, NFS, Coda).
+ */
+static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
+{
+       int fd, dirlen = directory_size(filename);
+
+       if (dirlen + 20 > bufsiz) {
+               errno = ENAMETOOLONG;
+               return -1;
        }
+       memcpy(buffer, filename, dirlen);
+       strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
+       fd = mkstemp(buffer);
+       if (fd < 0 && dirlen) {
+               /* Make sure the directory exists */
+               buffer[dirlen-1] = 0;
+               if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
+                       return -1;
 
-       if (errno != ENOENT) {
-               return error("sha1 file %s: %s\n", filename, strerror(errno));
+               /* Try again */
+               strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
+               fd = mkstemp(buffer);
        }
+       return fd;
+}
 
-       snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
+static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
+                             void *buf, unsigned long len, time_t mtime)
+{
+       int fd, size, ret;
+       unsigned char *compressed;
+       z_stream stream;
+       char *filename;
+       static char tmpfile[PATH_MAX];
 
-       fd = mkstemp(tmpfile);
+       filename = sha1_file_name(sha1);
+       fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
        if (fd < 0) {
                if (errno == EPERM)
                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
@@ -2177,156 +2178,53 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
 
        if (write_buffer(fd, compressed, size) < 0)
                die("unable to write sha1 file");
-       fchmod(fd, 0444);
-       if (close(fd))
-               die("unable to write sha1 file");
+       close_sha1_file(fd);
        free(compressed);
 
+       if (mtime) {
+               struct utimbuf utb;
+               utb.actime = mtime;
+               utb.modtime = mtime;
+               if (utime(tmpfile, &utb) < 0)
+                       warning("failed utime() on %s: %s",
+                               tmpfile, strerror(errno));
+       }
+
        return move_temp_to_file(tmpfile, filename);
 }
 
-/*
- * We need to unpack and recompress the object for writing
- * it out to a different file.
- */
-static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
+int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
-       size_t size;
-       z_stream stream;
-       unsigned char *unpacked;
-       unsigned long len;
-       enum object_type type;
+       unsigned char sha1[20];
        char hdr[32];
        int hdrlen;
-       void *buf;
-
-       /* need to unpack and recompress it by itself */
-       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", typename(type), len) + 1;
-
-       /* Set it up */
-       memset(&stream, 0, sizeof(stream));
-       deflateInit(&stream, zlib_compression_level);
-       size = deflateBound(&stream, len + hdrlen);
-       buf = xmalloc(size);
-
-       /* Compress it */
-       stream.next_out = buf;
-       stream.avail_out = size;
-
-       /* First header.. */
-       stream.next_in = (void *)hdr;
-       stream.avail_in = hdrlen;
-       while (deflate(&stream, 0) == Z_OK)
-               /* nothing */;
-
-       /* Then the data itself.. */
-       stream.next_in = unpacked;
-       stream.avail_in = len;
-       while (deflate(&stream, Z_FINISH) == Z_OK)
-               /* nothing */;
-       deflateEnd(&stream);
-       free(unpacked);
-
-       *objsize = stream.total_out;
-       return buf;
-}
-
-int write_sha1_to_fd(int fd, const unsigned char *sha1)
-{
-       int retval;
-       unsigned long objsize;
-       void *buf = map_sha1_file(sha1, &objsize);
-
-       if (buf) {
-               retval = write_buffer(fd, buf, objsize);
-               munmap(buf, objsize);
-               return retval;
-       }
 
-       buf = repack_object(sha1, &objsize);
-       retval = write_buffer(fd, buf, objsize);
-       free(buf);
-       return retval;
+       /* Normally if we have it in the pack then we do not bother writing
+        * it out into .git/objects/??/?{38} file.
+        */
+       write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
+       if (returnsha1)
+               hashcpy(returnsha1, sha1);
+       if (has_sha1_file(sha1))
+               return 0;
+       return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
 }
 
-int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
-                      size_t bufsize, size_t *bufposn)
+int force_object_loose(const unsigned char *sha1, time_t mtime)
 {
-       char tmpfile[PATH_MAX];
-       int local;
-       z_stream stream;
-       unsigned char real_sha1[20];
-       unsigned char discard[4096];
-       int ret;
-       SHA_CTX c;
-
-       snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
-
-       local = mkstemp(tmpfile);
-       if (local < 0) {
-               if (errno == EPERM)
-                       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));
-       }
-
-       memset(&stream, 0, sizeof(stream));
-
-       inflateInit(&stream);
-
-       SHA1_Init(&c);
-
-       do {
-               ssize_t size;
-               if (*bufposn) {
-                       stream.avail_in = *bufposn;
-                       stream.next_in = (unsigned char *) buffer;
-                       do {
-                               stream.next_out = discard;
-                               stream.avail_out = sizeof(discard);
-                               ret = inflate(&stream, Z_SYNC_FLUSH);
-                               SHA1_Update(&c, discard, sizeof(discard) -
-                                           stream.avail_out);
-                       } while (stream.avail_in && ret == Z_OK);
-                       if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
-                               die("unable to write sha1 file");
-                       memmove(buffer, buffer + *bufposn - stream.avail_in,
-                               stream.avail_in);
-                       *bufposn = stream.avail_in;
-                       if (ret != Z_OK)
-                               break;
-               }
-               size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
-               if (size <= 0) {
-                       close(local);
-                       unlink(tmpfile);
-                       if (!size)
-                               return error("Connection closed?");
-                       perror("Reading from connection");
-                       return -1;
-               }
-               *bufposn += size;
-       } while (1);
-       inflateEnd(&stream);
-
-       fchmod(local, 0444);
-       if (close(local) != 0)
-               die("unable to write sha1 file");
-       SHA1_Final(real_sha1, &c);
-       if (ret != Z_STREAM_END) {
-               unlink(tmpfile);
-               return error("File %s corrupted", sha1_to_hex(sha1));
-       }
-       if (hashcmp(sha1, real_sha1)) {
-               unlink(tmpfile);
-               return error("File %s has bad hash", sha1_to_hex(sha1));
-       }
+       void *buf;
+       unsigned long len;
+       enum object_type type;
+       char hdr[32];
+       int hdrlen;
 
-       return move_temp_to_file(tmpfile, sha1_file_name(sha1));
+       if (has_loose_object(sha1))
+               return 0;
+       buf = read_packed_sha1(sha1, &type, &len);
+       if (!buf)
+               return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+       hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
+       return write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
 }
 
 int has_pack_index(const unsigned char *sha1)
@@ -2353,12 +2251,11 @@ int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
 
 int has_sha1_file(const unsigned char *sha1)
 {
-       struct stat st;
        struct pack_entry e;
 
        if (find_pack_entry(sha1, &e, NULL))
                return 1;
-       return find_sha1_file(sha1, &st) ? 1 : 0;
+       return has_loose_object(sha1);
 }
 
 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)