Split "git-pull-script" into two parts
[gitweb.git] / sha1_file.c
index db2880e389e556dd3a5eef02aa8a3bb235528057..e6ce455ae90bd430f2128f454bdb6e0575412486 100644 (file)
@@ -45,6 +45,48 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
        return 0;
 }
 
+int get_sha1_file(const char *path, unsigned char *result)
+{
+       char buffer[60];
+       int fd = open(path, O_RDONLY);
+       int len;
+
+       if (fd < 0)
+               return -1;
+       len = read(fd, buffer, sizeof(buffer));
+       close(fd);
+       if (len < 40)
+               return -1;
+       return get_sha1_hex(buffer, result);
+}
+
+int get_sha1(const char *str, unsigned char *sha1)
+{
+       static char pathname[PATH_MAX];
+       static const char *prefix[] = {
+               "",
+               "refs",
+               "refs/tags",
+               "refs/heads",
+               "refs/snap",
+               NULL
+       };
+       const char *gitdir;
+       const char **p;
+
+       if (!get_sha1_hex(str, sha1))
+               return 0;
+
+       gitdir = ".git";
+       for (p = prefix; *p; p++) {
+               snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str);
+               if (!get_sha1_file(pathname, sha1))
+                       return 0;
+       }
+
+       return -1;
+}
+
 char * sha1_to_hex(const unsigned char *sha1)
 {
        static char buffer[50];
@@ -189,44 +231,49 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
        return NULL;
 }
 
-void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
-                                        unsigned long *size,
-                                        unsigned char *tree_sha1_return)
+void *read_object_with_reference(const unsigned char *sha1,
+                                const unsigned char *required_type,
+                                unsigned long *size,
+                                unsigned char *actual_sha1_return)
 {
        char type[20];
        void *buffer;
        unsigned long isize;
-       int was_commit = 0;
-       unsigned char tree_sha1[20];
-
-       buffer = read_sha1_file(sha1, type, &isize);
-
-       /* 
-        * We might have read a commit instead of a tree, in which case
-        * we parse out the tree_sha1 and attempt to read from there.
-        * (buffer + 5) is because the tree sha1 is always at offset 5
-        * in a commit record ("tree ").
-        */
-       if (buffer &&
-           !strcmp(type, "commit") &&
-           !get_sha1_hex(buffer + 5, tree_sha1)) {
-               free(buffer);
-               buffer = read_sha1_file(tree_sha1, type, &isize);
-               was_commit = 1;
-       }
+       unsigned char actual_sha1[20];
 
-       /*
-        * Now do we have something and if so is it a tree?
-        */
-       if (!buffer || strcmp(type, "tree")) {
-               free(buffer);
-               return NULL;
-       }
+       memcpy(actual_sha1, sha1, 20);
+       while (1) {
+               int ref_length = -1;
+               const char *ref_type = NULL;
 
-       *size = isize;
-       if (tree_sha1_return)
-               memcpy(tree_sha1_return, was_commit ? tree_sha1 : sha1, 20);
-       return buffer;
+               buffer = read_sha1_file(actual_sha1, type, &isize);
+               if (!buffer)
+                       return NULL;
+               if (!strcmp(type, required_type)) {
+                       *size = isize;
+                       if (actual_sha1_return)
+                               memcpy(actual_sha1_return, actual_sha1, 20);
+                       return buffer;
+               }
+               /* Handle references */
+               else if (!strcmp(type, "commit"))
+                       ref_type = "tree ";
+               else if (!strcmp(type, "tag"))
+                       ref_type = "object ";
+               else {
+                       free(buffer);
+                       return NULL;
+               }
+               ref_length = strlen(ref_type);
+
+               if (memcmp(buffer, ref_type, ref_length) ||
+                   get_sha1_hex(buffer + ref_length, actual_sha1)) {
+                       free(buffer);
+                       return NULL;
+               }
+               /* Now we have the ID of the referred-to object in
+                * actual_sha1.  Check again. */
+       }
 }
 
 int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1)
@@ -237,8 +284,9 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha
        unsigned char sha1[20];
        SHA_CTX c;
        char *filename;
+       static char tmpfile[PATH_MAX];
        char hdr[50];
-       int fd, hdrlen;
+       int fd, hdrlen, ret;
 
        /* Generate the header */
        hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
@@ -253,18 +301,28 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha
                memcpy(returnsha1, sha1, 20);
 
        filename = sha1_file_name(sha1);
-       fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0) {
-               if (errno != EEXIST)
-                       return -1;
-
+       fd = open(filename, O_RDONLY);
+       if (fd >= 0) {
                /*
-                * We might do collision checking here, but we'd need to
-                * uncompress the old file and check it. Later.
+                * FIXME!!! We might do collision checking here, but we'd
+                * need to uncompress the old file and check it. Later.
                 */
+               close(fd);
                return 0;
        }
 
+       if (errno != ENOENT) {
+               fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
+               return -1;
+       }
+
+       snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
+       fd = mkstemp(tmpfile);
+       if (fd < 0) {
+               fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
+               return -1;
+       }
+
        /* Set it up */
        memset(&stream, 0, sizeof(stream));
        deflateInit(&stream, Z_BEST_COMPRESSION);
@@ -291,54 +349,34 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha
 
        if (write(fd, compressed, size) != size)
                die("unable to write file");
+       fchmod(fd, 0444);
        close(fd);
-               
-       return 0;
-}
-
-static inline int collision_check(char *filename, void *buf, unsigned int size)
-{
-#ifdef COLLISION_CHECK
-       void *map;
-       int fd = open(filename, O_RDONLY);
-       struct stat st;
-       int cmp;
-
-       /* Unreadable object, or object went away? Strange. */
-       if (fd < 0)
-               return -1;
-
-       if (fstat(fd, &st) < 0 || size != st.st_size)
-               return -1;
-
-       map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-       close(fd);
-       if (map == MAP_FAILED)
-               return -1;
-       cmp = memcmp(buf, map, size);
-       munmap(map, size);
-       if (cmp)
-               return -1;
-#endif
-       return 0;
-}
 
-int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
-{
-       char *filename = sha1_file_name(sha1);
-       int fd;
+       ret = link(tmpfile, filename);
+       if (ret < 0) {
+               ret = errno;
 
-       fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0) {
-               if (errno != EEXIST)
+               /*
+                * 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;
-               if (collision_check(filename, buf, size))
-                       return error("SHA1 collision detected!"
-                                       " This is bad, bad, BAD!\a\n");
-               return 0;
+               }
+               /* FIXME!!! Collision check here ? */
        }
-       write(fd, buf, size);
-       close(fd);
+
        return 0;
 }
 
@@ -413,3 +451,22 @@ int has_sha1_file(const unsigned char *sha1)
                return 1;
        return 0;
 }
+
+int index_fd(unsigned char *sha1, int fd, struct stat *st)
+{
+       unsigned long size = st->st_size;
+       void *buf;
+       int ret;
+
+       buf = "";
+       if (size)
+               buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+       close(fd);
+       if ((int)(long)buf == -1)
+               return -1;
+
+       ret = write_sha1_file(buf, size, "blob", sha1);
+       if (size)
+               munmap(buf, size);
+       return ret;
+}