X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=sha1_file.c;h=942b673dc3c7fa9f057c5c452e3a1b73eaeb8707;hb=071c41a047e4c851836669648716e361f8e0b5ad;hp=bf8fd6aa5fd76c119dd1a84cc540a5219e1987e4;hpb=a1df57abb90d456b6b600b8cf6a5232a39cd3f5e;p=git.git

diff --git a/sha1_file.c b/sha1_file.c
index bf8fd6aa..942b673d 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -59,6 +59,38 @@ int get_sha1_file(const char *path, unsigned char *result)
 	return get_sha1_hex(buffer, result);
 }
 
+static char *git_dir, *git_object_dir, *git_index_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_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);
+	}
+}
+
+char *get_object_directory(void)
+{
+	if (!git_object_dir)
+		setup_git_env();
+	return git_object_dir;
+}
+
+char *get_index_file(void)
+{
+	if (!git_index_file)
+		setup_git_env();
+	return git_index_file;
+}
+
 int get_sha1(const char *str, unsigned char *sha1)
 {
 	static char pathname[PATH_MAX];
@@ -70,15 +102,16 @@ int get_sha1(const char *str, unsigned char *sha1)
 		"refs/snap",
 		NULL
 	};
-	const char *gitdir;
 	const char **p;
 
 	if (!get_sha1_hex(str, sha1))
 		return 0;
 
-	gitdir = ".git";
+	if (!git_dir)
+		setup_git_env();
 	for (p = prefix; *p; p++) {
-		snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str);
+		snprintf(pathname, sizeof(pathname), "%s/%s/%s",
+			 git_dir, *p, str);
 		if (!get_sha1_file(pathname, sha1))
 			return 0;
 	}
@@ -120,7 +153,7 @@ static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
  *
  * Also note that this returns the location for creating.  Reading
  * SHA1 file can happen from any alternate directory listed in the
- * SHA1_FILE_DIRECTORIES environment variable if it is not found in
+ * DB_ENVIRONMENT environment variable if it is not found in
  * the primary object database.
  */
 char *sha1_file_name(const unsigned char *sha1)
@@ -128,7 +161,7 @@ char *sha1_file_name(const unsigned char *sha1)
 	static char *name, *base;
 
 	if (!base) {
-		char *sha1_file_directory = get_object_directory();
+		const char *sha1_file_directory = get_object_directory();
 		int len = strlen(sha1_file_directory);
 		base = xmalloc(len + 60);
 		memcpy(base, sha1_file_directory, len);
@@ -141,20 +174,40 @@ char *sha1_file_name(const unsigned char *sha1)
 	return base;
 }
 
-static struct alternate_object_database
-{
+static struct alternate_object_database {
 	char *base;
 	char *name;
 } *alt_odb;
 
+/*
+ * 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.
+ */
 static void prepare_alt_odb(void)
 {
 	int pass, totlen, i;
-	void *buf;
 	const char *cp, *last;
 	char *op = 0;
-	const char *alt = getenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
-
+	const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
+
+	/* 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;
@@ -182,7 +235,7 @@ static void prepare_alt_odb(void)
 		} while (*cp);
 		if (pass)
 			break;
-		alt_odb = buf = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
+		alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
 		alt_odb[i].base = alt_odb[i].name = 0;
 		op = (char*)(&alt_odb[i+1]);
 	}
@@ -412,7 +465,7 @@ int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned cha
 	stream.next_in = hdr;
 	stream.avail_in = hdrlen;
 	while (deflate(&stream, 0) == Z_OK)
-		/* nothing */
+		/* nothing */;
 
 	/* Then the data itself.. */
 	stream.next_in = buf;