[PATCH 12/16] subtree: rewriting outgoing commits
Which is exactly the opposite of rewriting incoming commits.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
subtree.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
subtree.h | 1 +
2 files changed, 174 insertions(+), 0 deletions(-)
diff --git a/subtree.c b/subtree.c
index 8c075be..739ff5f 100644
--- a/subtree.c
+++ b/subtree.c
@@ -359,3 +359,176 @@ void subtree_import()
if (revs.pending.nr)
free(revs.pending.objects);
}
+
+/*
+ * The opposite of narrow_tree(). Put the subtree back to the original tree.
+ */
+static int widen_tree(const unsigned char *sha1,
+ unsigned char *newsha1,
+ const unsigned char *subtree_sha1,
+ const char *prefix)
+{
+ struct tree_desc desc;
+ struct name_entry entry;
+ struct strbuf buffer;
+ const char *slash;
+ int subtree_len;
+ enum object_type type;
+ unsigned long size;
+ char *tree;
+
+ slash = strchr(prefix, '/');
+ subtree_len = slash ? slash - prefix : strlen(prefix);
+
+ tree = read_sha1_file(sha1, &type, &size);
+ if (type != OBJ_TREE)
+ die("%s is not a tree", sha1_to_hex(sha1));
+
+ init_tree_desc(&desc, tree, size);
+ strbuf_init(&buffer, 8192);
+ while (tree_entry(&desc, &entry)) {
+ strbuf_addf(&buffer, "%o %.*s%c", entry.mode, strlen(entry.path), entry.path, '\0');
+
+ if (S_ISDIR(entry.mode) &&
+ subtree_len == strlen(entry.path) &&
+ !strncmp(entry.path, prefix, subtree_len)) {
+ unsigned char newtree_sha1[20];
+
+ if (slash && slash[1]) /* trailing slash does not count */
+ widen_tree(entry.sha1, newtree_sha1, subtree_sha1,
+ prefix+subtree_len+1);
+ else
+ /* replace the tree */
+ memcpy(newtree_sha1, subtree_sha1, 20);
+
+ strbuf_add(&buffer, newtree_sha1, 20);
+ }
+ else
+ strbuf_add(&buffer, entry.sha1, 20);
+ }
+ free(tree);
+
+ if (write_sha1_file(buffer.buf, buffer.len, tree_type, newsha1)) {
+ error("Could not write replaced tree for %s", sha1_to_hex(sha1));
+ strbuf_release(&buffer);
+ return 1;
+ }
+ strbuf_release(&buffer);
+ return 0;
+}
+
+static int find_subtree(const unsigned char *sha1, unsigned char *newsha1, const char *prefix)
+{
+ struct tree_desc desc;
+ struct name_entry entry;
+ const char *slash;
+ enum object_type type;
+ unsigned long size;
+ int subtree_len;
+ char *tree;
+
+ slash = strchr(prefix, '/');
+ subtree_len = slash ? slash - prefix : strlen(prefix);
+
+ tree = read_sha1_file(sha1, &type, &size);
+ if (type != OBJ_TREE)
+ die("%s is not a tree", sha1_to_hex(sha1));
+
+ init_tree_desc(&desc, tree, size);
+ while (tree_entry(&desc, &entry)) {
+ if (!S_ISDIR(entry.mode))
+ continue;
+
+ if (subtree_len == strlen(entry.path) &&
+ !strncmp(entry.path, prefix, subtree_len)) {
+
+ if (slash && slash[1]) { /* trailing slash does not count */
+ if (find_subtree(entry.sha1, newsha1, prefix+subtree_len+1))
+ return 1;
+ }
+ else
+ memcpy(newsha1, entry.sha1, 20);
+ free(tree);
+ return 0;
+ }
+ }
+ free(tree);
+
+ return 1;
+}
+
+/* The opposite of shadow_commit() */
+static int expose_commit(const unsigned char *sha1, unsigned char *newsha1,
+ const unsigned char *basesha1,
+ const char *prefix, FILE *fp)
+{
+ unsigned char treesha1[20], subtree_sha1[20];
+ enum object_type type;
+ unsigned long size, base_size;
+ void *base_buffer, *buffer;
+ int saved_read_replace_refs = read_replace_refs;
+
+ /* Get subtree from the new commit, sha1 */
+ read_replace_refs = 0;
+ buffer = read_sha1_file(sha1, &type, &size);
+ read_replace_refs = saved_read_replace_refs;
+ get_sha1_hex(buffer+5, treesha1);
+
+ if (!buffer || type != OBJ_COMMIT ||
+ find_subtree(treesha1, subtree_sha1, prefix)) {
+ free(buffer);
+ error("Failed to find subtree tree in base commit %s", sha1_to_hex(sha1));
+ return 1;
+ }
+
+ /* Get the old base tree from basesha1 */
+ read_replace_refs = 0;
+ base_buffer = read_sha1_file(basesha1, &type, &base_size);
+ read_replace_refs = saved_read_replace_refs;
+ get_sha1_hex(base_buffer+5, treesha1);
+
+ if (!buffer || type != OBJ_COMMIT ||
+ widen_tree(treesha1, newsha1, subtree_sha1, prefix)) {
+ free(buffer);
+ error("Failed to widen tree for commit %s", sha1_to_hex(sha1));
+ return 1;
+ }
+ free(base_buffer);
+
+ /* replace new tree in */
+ memcpy((char*)buffer+5, sha1_to_hex(newsha1), 40);
+
+ if (write_sha1_file(buffer, size, commit_type, newsha1)) {
+ free(buffer);
+ error("Could not write replaced commit for %s", sha1_to_hex(sha1));
+ return 1;
+ }
+
+ if (fp) {
+ char buf[82];
+ memcpy(buf, sha1_to_hex(newsha1), 40);
+ buf[40] = ' ';
+ memcpy(buf+41, sha1_to_hex(sha1), 40);
+ buf[81] = '\n';
+ fwrite(buf, 82, 1, fp);
+ }
+ free(buffer);
+
+ return 0;
+}
+
+int subtree_export(unsigned char *sha1, unsigned char *basesha1, unsigned char *newsha1)
+{
+ FILE *fp;
+
+ fp = fopen(git_path("subtree"), "a+");
+ if (expose_commit(sha1, newsha1, basesha1, core_subtree, fp))
+ die("Failed to rewrite commit %s", sha1_to_hex(sha1));
+ fclose(fp);
+
+ if (subtree_commit)
+ free(subtree_commit);
+ prepare_subtree_commit();
+
+ return 0;
+}
diff --git a/subtree.h b/subtree.h
index 3512e2a..081838f 100644
--- a/subtree.h
+++ b/subtree.h
@@ -1,3 +1,4 @@
void prepare_subtree_commit();
const unsigned char *subtree_lookup_object(const unsigned char *sha1);
void subtree_import();
+int subtree_export(unsigned char *sha1, unsigned char *basesha1, unsigned char *newsha1);
--
1.7.1.rc1.69.g24c2f7
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>