1 files changed, 148 insertions, 0 deletions
diff --git a/shallow.c b/shallow.c
new file mode 100644
index 0000000000..cbe2526d8c
--- /dev/null
+++ b/shallow.c
@@ -0,0 +1,148 @@
+#include "cache.h"
+#include "commit.h"
+#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)
+{
+	struct commit_graft *graft =
+		xmalloc(sizeof(struct commit_graft));
+	struct commit *commit = lookup_commit(sha1);
+
+	hashcpy(graft->sha1, sha1);
+	graft->nr_parent = -1;
+	if (commit && commit->object.parsed)
+		commit->parents = NULL;
+	return register_commit_graft(graft, 0);
+}
+
+int is_repository_shallow(void)
+{
+	FILE *fp;
+	char buf[1024];
+	const char *path = alternate_shallow_file;
+
+	if (is_shallow >= 0)
+		return is_shallow;
+
+	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;
+	}
+	is_shallow = 1;
+
+	while (fgets(buf, sizeof(buf), fp)) {
+		unsigned char sha1[20];
+		if (get_sha1_hex(buf, sha1))
+			die("bad shallow line: %s", buf);
+		register_shallow(sha1);
+	}
+	fclose(fp);
+	return is_shallow;
+}
+
+struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
+		int shallow_flag, int not_shallow_flag)
+{
+	int i = 0, cur_depth = 0;
+	struct commit_list *result = NULL;
+	struct object_array stack = OBJECT_ARRAY_INIT;
+	struct commit *commit = NULL;
+
+	while (commit || i < heads->nr || stack.nr) {
+		struct commit_list *p;
+		if (!commit) {
+			if (i < heads->nr) {
+				commit = (struct commit *)
+					deref_tag(heads->objects[i++].item, NULL, 0);
+				if (!commit || commit->object.type != OBJ_COMMIT) {
+					commit = NULL;
+					continue;
+				}
+				if (!commit->util)
+					commit->util = xmalloc(sizeof(int));
+				*(int *)commit->util = 0;
+				cur_depth = 0;
+			} else {
+				commit = (struct commit *)
+					stack.objects[--stack.nr].item;
+				cur_depth = *(int *)commit->util;
+			}
+		}
+		if (parse_commit(commit))
+			die("invalid commit");
+		cur_depth++;
+		if (cur_depth >= depth) {
+			commit_list_insert(commit, &result);
+			commit->object.flags |= shallow_flag;
+			commit = NULL;
+			continue;
+		}
+		commit->object.flags |= not_shallow_flag;
+		for (p = commit->parents, commit = NULL; p; p = p->next) {
+			if (!p->item->util) {
+				int *pointer = xmalloc(sizeof(int));
+				p->item->util = pointer;
+				*pointer =  cur_depth;
+			} else {
+				int *pointer = p->item->util;
+				if (cur_depth >= *pointer)
+					continue;
+				*pointer = cur_depth;
+			}
+			if (cur_depth < depth) {
+				if (p->next)
+					add_object_array(&p->item->object,
+							NULL, &stack);
+				else {
+					commit = p->item;
+					cur_depth = *(int *)commit->util;
+				}
+			} else {
+				commit_list_insert(p->item, &result);
+				p->item->object.flags |= shallow_flag;
+			}
+		}
+	}
+
+	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");
+}