X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=sha1_file.c;h=66382027816e8ec3a97c40f6849c62454f2ad0f2;hb=f8ff0c0641a14770a2214fffbd4271b1ea3a0d61;hp=a17a6d13b27630aec40a5e7ee48a7b2d1874d05a;hpb=6b7242aa1acc3c7835f80522914ffc4b2e789a29;p=git.git

diff --git a/sha1_file.c b/sha1_file.c
index a17a6d13..66382027 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -50,22 +50,22 @@ 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);
+	git_dir = getenv(GIT_DIR_ENVIRONMENT);
 	if (!git_dir)
 		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
-	git_object_dir = gitenv(DB_ENVIRONMENT);
+	git_object_dir = getenv(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);
+	git_index_file = getenv(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);
+	git_graft_file = getenv(GRAFT_ENVIRONMENT);
 	if (!git_graft_file)
 		git_graft_file = strdup(git_path("info/grafts"));
 }
@@ -222,84 +222,123 @@ 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 exactly in the same format as that environment
+ * variable.  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;
+	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) {
+			/* 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);
+			*alt_odb_tail = ent;
+			alt_odb_tail = &(ent->next);
+			ent->next = NULL;
+			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);
+			}
+			else
+				memcpy(ent->base, last, pfxlen);
+			ent->name = ent->base + pfxlen + 1;
+			ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
+			ent->base[entlen-1] = 0;
+		}
+		while (cp < ep && *cp == sep)
+			cp++;
+		last = cp;
+	}
+}
 
-	if (alt_odb)
+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;
-	/* 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++;
-			}
-			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]);
 	}
+	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;
 }
@@ -460,12 +499,18 @@ struct packed_git *add_packed_git(char *path, int path_len)
 
 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);
@@ -522,18 +567,18 @@ 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_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[0] = 0;
+		prepare_packed_git_one(alt->base);
 	}
+	run_once = 1;
 }
 
 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
@@ -1165,6 +1210,7 @@ void *read_object_with_reference(const unsigned char *sha1,
 			free(buffer);
 			return NULL;
 		}
+		free(buffer);
 		/* Now we have the ID of the referred-to object in
 		 * actual_sha1.  Check again. */
 	}
@@ -1296,8 +1342,11 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 	ssize_t size;
 	unsigned long objsize;
 	int posn = 0;
-	void *buf = map_sha1_file_internal(sha1, &objsize);
+	void *map = map_sha1_file_internal(sha1, &objsize);
+	void *buf = map;
+	void *temp_obj = NULL;
 	z_stream stream;
+
 	if (!buf) {
 		unsigned char *unpacked;
 		unsigned long len;
@@ -1313,7 +1362,7 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 		memset(&stream, 0, sizeof(stream));
 		deflateInit(&stream, Z_BEST_COMPRESSION);
 		size = deflateBound(&stream, len + hdrlen);
-		buf = xmalloc(size);
+		temp_obj = buf = xmalloc(size);
 
 		/* Compress it */
 		stream.next_out = buf;
@@ -1331,6 +1380,7 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 		while (deflate(&stream, Z_FINISH) == Z_OK)
 			/* nothing */;
 		deflateEnd(&stream);
+		free(unpacked);
 		
 		objsize = stream.total_out;
 	}
@@ -1347,6 +1397,12 @@ int write_sha1_to_fd(int fd, const unsigned char *sha1)
 		}
 		posn += size;
 	} while (posn < objsize);
+
+	if (map)
+		munmap(map, objsize);
+	if (temp_obj)
+		free(temp_obj);
+
 	return 0;
 }
 
@@ -1377,7 +1433,7 @@ 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);