fetch-pack: prepare updated shallow file before fetching the pack

[thirdparty/git.git] / shallow.c

diff --git a/shallow.c b/shallow.c
index 6be915f38f1fe8dbe0a22c4cd8ae2569331f483f..cbe2526d8c2b2643957eea2729a16269a7a74fab 100644 (file)
--- a/shallow.c
+++ b/shallow.c
@@ -3,6 +3,16 @@
 #include "tag.h"
 
 static int is_shallow = -1;
+static struct stat shallow_stat;
+static char *alternate_shallow_file;
+
+void set_alternate_shallow_file(const char *path)
+{
+       if (is_shallow != -1)
+               die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
+       free(alternate_shallow_file);
+       alternate_shallow_file = path ? xstrdup(path) : NULL;
+}
 
 int register_shallow(const unsigned char *sha1)
 {
@@ -21,12 +31,21 @@ int is_repository_shallow(void)
 {
        FILE *fp;
        char buf[1024];
+       const char *path = alternate_shallow_file;
 
        if (is_shallow >= 0)
                return is_shallow;
 
-       fp = fopen(git_path("shallow"), "r");
-       if (!fp) {
+       if (!path)
+               path = git_path("shallow");
+       /*
+        * fetch-pack sets '--shallow-file ""' as an indicator that no
+        * shallow file should be used. We could just open it and it
+        * will likely fail. But let's do an explicit check instead.
+        */
+       if (!*path ||
+           stat(path, &shallow_stat) ||
+           (fp = fopen(path, "r")) == NULL) {
                is_shallow = 0;
                return is_shallow;
        }
@@ -108,3 +127,22 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 
        return result;
 }
+
+void check_shallow_file_for_update(void)
+{
+       struct stat st;
+
+       if (!is_shallow)
+               return;
+       else if (is_shallow == -1)
+               die("BUG: shallow must be initialized by now");
+
+       if (stat(git_path("shallow"), &st))
+               die("shallow file was removed during fetch");
+       else if (st.st_mtime != shallow_stat.st_mtime
+#ifdef USE_NSEC
+                || ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
+#endif
+                  )
+               die("shallow file was changed during fetch");
+}