setup: add gentle version of read_gitfile

read_gitfile will die on most error cases. This makes it unsuitable
for speculative calls. Extract the core logic and provide a gentle
version that returns NULL on failure.

The first usecase of the new gentle version will be to probe for
submodules during git clean.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Erik Elfström <erik.elfstrom@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 571c98f5e2406afad1352fcaddd1efff1af65cc1..25578cbf3cd29ca2a4f4fc2a4423eb8136cff164 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -446,7 +446,16 @@ extern int get_common_dir(struct strbuf *sb, const char *gitdir);
 extern const char *get_git_namespace(void);
 extern const char *strip_namespace(const char *namespaced_ref);
 extern const char *get_git_work_tree(void);
 extern const char *get_git_namespace(void);
 extern const char *strip_namespace(const char *namespaced_ref);
 extern const char *get_git_work_tree(void);

-extern const char *read_gitfile(const char *path);
+
+#define READ_GITFILE_ERR_STAT_FAILED 1
+#define READ_GITFILE_ERR_NOT_A_FILE 2
+#define READ_GITFILE_ERR_OPEN_FAILED 3
+#define READ_GITFILE_ERR_READ_FAILED 4
+#define READ_GITFILE_ERR_INVALID_FORMAT 5
+#define READ_GITFILE_ERR_NO_PATH 6
+#define READ_GITFILE_ERR_NOT_A_REPO 7
+extern const char *read_gitfile_gently(const char *path, int *return_error_code);
+#define read_gitfile(path) read_gitfile_gently((path), NULL)

 extern const char *resolve_gitdir(const char *suspect);
 extern void set_git_work_tree(const char *tree);
 
 extern const char *resolve_gitdir(const char *suspect);
 extern void set_git_work_tree(const char *tree);
 

diff --git a/setup.c b/setup.c
index 863ddfd938d29e58341bd2be5dd3b7ecd4db7df2..4748b6338d8fe338d4e001f9e9587ba349ab05a4 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -406,35 +406,53 @@ static void update_linked_gitdir(const char *gitfile, const char *gitdir)
 /*
  * Try to read the location of the git directory from the .git file,
  * return path to git directory if found.
 /*
  * Try to read the location of the git directory from the .git file,
  * return path to git directory if found.

+ *
+ * On failure, if return_error_code is not NULL, return_error_code
+ * will be set to an error code and NULL will be returned. If
+ * return_error_code is NULL the function will die instead (for most
+ * cases).

  */
  */

-const char *read_gitfile(const char *path)
+const char *read_gitfile_gently(const char *path, int *return_error_code)

 {
 {

-       char *buf;
-       char *dir;
+       int error_code = 0;
+       char *buf = NULL;
+       char *dir = NULL;

        const char *slash;
        struct stat st;
        int fd;
        ssize_t len;
 
        const char *slash;
        struct stat st;
        int fd;
        ssize_t len;
 

-       if (stat(path, &st))
-               return NULL;
-       if (!S_ISREG(st.st_mode))
-               return NULL;
+       if (stat(path, &st)) {
+               error_code = READ_GITFILE_ERR_STAT_FAILED;
+               goto cleanup_return;
+       }
+       if (!S_ISREG(st.st_mode)) {
+               error_code = READ_GITFILE_ERR_NOT_A_FILE;
+               goto cleanup_return;
+       }

        fd = open(path, O_RDONLY);
        fd = open(path, O_RDONLY);

-       if (fd < 0)
-               die_errno("Error opening '%s'", path);
+       if (fd < 0) {
+               error_code = READ_GITFILE_ERR_OPEN_FAILED;
+               goto cleanup_return;
+       }

        buf = xmalloc(st.st_size + 1);
        len = read_in_full(fd, buf, st.st_size);
        close(fd);
        buf = xmalloc(st.st_size + 1);
        len = read_in_full(fd, buf, st.st_size);
        close(fd);

-       if (len != st.st_size)
-               die("Error reading %s", path);
+       if (len != st.st_size) {
+               error_code = READ_GITFILE_ERR_READ_FAILED;
+               goto cleanup_return;
+       }

        buf[len] = '\0';
        buf[len] = '\0';

-       if (!starts_with(buf, "gitdir: "))
-               die("Invalid gitfile format: %s", path);
+       if (!starts_with(buf, "gitdir: ")) {
+               error_code = READ_GITFILE_ERR_INVALID_FORMAT;
+               goto cleanup_return;
+       }

        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
                len--;
        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
                len--;

-       if (len < 9)
-               die("No path in gitfile: %s", path);
+       if (len < 9) {
+               error_code = READ_GITFILE_ERR_NO_PATH;
+               goto cleanup_return;
+       }

        buf[len] = '\0';
        dir = buf + 8;
 
        buf[len] = '\0';
        dir = buf + 8;
 


@@ -448,14 +466,42 @@ const char *read_gitfile(const char *path)
                free(buf);
                buf = dir;
        }
                free(buf);
                buf = dir;
        }

-
-       if (!is_git_directory(dir))
-               die("Not a git repository: %s", dir);
-
+       if (!is_git_directory(dir)) {
+               error_code = READ_GITFILE_ERR_NOT_A_REPO;
+               goto cleanup_return;
+       }

        update_linked_gitdir(path, dir);
        path = real_path(dir);
 
        update_linked_gitdir(path, dir);
        path = real_path(dir);
 

+cleanup_return:

        free(buf);
        free(buf);

+
+       if (return_error_code)
+               *return_error_code = error_code;
+
+       if (error_code) {
+               if (return_error_code)
+                       return NULL;
+
+               switch (error_code) {
+               case READ_GITFILE_ERR_STAT_FAILED:
+               case READ_GITFILE_ERR_NOT_A_FILE:
+                       return NULL;
+               case READ_GITFILE_ERR_OPEN_FAILED:
+                       die_errno("Error opening '%s'", path);
+               case READ_GITFILE_ERR_READ_FAILED:
+                       die("Error reading %s", path);
+               case READ_GITFILE_ERR_INVALID_FORMAT:
+                       die("Invalid gitfile format: %s", path);
+               case READ_GITFILE_ERR_NO_PATH:
+                       die("No path in gitfile: %s", path);
+               case READ_GITFILE_ERR_NOT_A_REPO:
+                       die("Not a git repository: %s", dir);
+               default:
+                       assert(0);
+               }
+       }
+

        return path;
 }
 
        return path;
 }