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authorLinus Torvalds <torvalds@osdl.org>2005-10-21 04:25:09 (GMT)
committerJunio C Hamano <junkio@cox.net>2005-10-23 05:49:52 (GMT)
commitcf4845441c3931731643859dc80a79e52bcd3e0f (patch)
tree0ef1266d6640a6837ae8db89201f0b108b544d09 /rev-list.c
parentac1b3d1248f36b26c2eab55022b9a54bde36b1ee (diff)
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Teach git-rev-list to follow just a specified set of files
This is the first cut at a git-rev-list that knows to ignore commits that don't change a certain file (or set of files). NOTE! For now it only prunes _merge_ commits, and follows the parent where there are no differences in the set of files specified. In the long run, I'd like to make it re-write the straight-line history too, but for now the merge simplification is much more fundamentally important (the rewriting of straight-line history is largely a separate simplification phase, but the merge simplification needs to happen early if we want to optimize away unnecessary commit parsing). If all parents of a merge change some of the files, the merge is left as is, so the end result is in no way guaranteed to be a linear history, but it will often be a lot /more/ linear than the full tree, since it prunes out parents that didn't matter for that set of files. As an example from the current kernel: [torvalds@g5 linux]$ git-rev-list HEAD | wc -l 9885 [torvalds@g5 linux]$ git-rev-list HEAD -- Makefile | wc -l 4084 [torvalds@g5 linux]$ git-rev-list HEAD -- drivers/usb | wc -l 5206 and you can also use 'gitk' to more visually see the pruning of the history tree, with something like gitk -- drivers/usb showing a simplified history that tries to follow the first parent in a merge that is the parent that fully defines drivers/usb/. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'rev-list.c')
-rw-r--r--rev-list.c129
1 files changed, 125 insertions, 4 deletions
diff --git a/rev-list.c b/rev-list.c
index 3a32e40..b5dbb9f 100644
--- a/rev-list.c
+++ b/rev-list.c
@@ -5,6 +5,7 @@
#include "tree.h"
#include "blob.h"
#include "epoch.h"
+#include "diff.h"
#define SEEN (1u << 0)
#define INTERESTING (1u << 1)
@@ -44,6 +45,7 @@ static int show_breaks = 0;
static int stop_traversal = 0;
static int topo_order = 0;
static int no_merges = 0;
+static const char **paths = NULL;
static void show_commit(struct commit *commit)
{
@@ -377,18 +379,129 @@ static void mark_edges_uninteresting(struct commit_list *list)
}
}
+static int is_different = 0;
+
+static void file_add_remove(struct diff_options *options,
+ int addremove, unsigned mode,
+ const unsigned char *sha1,
+ const char *base, const char *path)
+{
+ is_different = 1;
+}
+
+static void file_change(struct diff_options *options,
+ unsigned old_mode, unsigned new_mode,
+ const unsigned char *old_sha1,
+ const unsigned char *new_sha1,
+ const char *base, const char *path)
+{
+ is_different = 1;
+}
+
+static struct diff_options diff_opt = {
+ .recursive = 1,
+ .add_remove = file_add_remove,
+ .change = file_change,
+};
+
+static struct commit *try_to_simplify_merge(struct commit *commit, struct commit_list *parent)
+{
+ if (!commit->tree)
+ return NULL;
+
+ while (parent) {
+ struct commit *p = parent->item;
+ parent = parent->next;
+ parse_commit(p);
+ if (!p->tree)
+ continue;
+ is_different = 0;
+ if (diff_tree_sha1(commit->tree->object.sha1,
+ p->tree->object.sha1, "", &diff_opt) < 0)
+ continue;
+ if (!is_different)
+ return p;
+ }
+ return NULL;
+}
+
+static void add_parents_to_list(struct commit *commit, struct commit_list **list)
+{
+ struct commit_list *parent = commit->parents;
+
+ /*
+ * If the commit is uninteresting, don't try to
+ * prune parents - we want the maximal uninteresting
+ * set.
+ *
+ * Normally we haven't parsed the parent
+ * yet, so we won't have a parent of a parent
+ * here. However, it may turn out that we've
+ * reached this commit some other way (where it
+ * wasn't uninteresting), in which case we need
+ * to mark its parents recursively too..
+ */
+ if (commit->object.flags & UNINTERESTING) {
+ while (parent) {
+ struct commit *p = parent->item;
+ parent = parent->next;
+ parse_commit(p);
+ p->object.flags |= UNINTERESTING;
+ if (p->parents)
+ mark_parents_uninteresting(p);
+ if (p->object.flags & SEEN)
+ continue;
+ p->object.flags |= SEEN;
+ insert_by_date(p, list);
+ }
+ return;
+ }
+
+ /*
+ * Ok, the commit wasn't uninteresting. If it
+ * is a merge, try to find the parent that has
+ * no differences in the path set if one exists.
+ */
+ if (paths && parent && parent->next) {
+ struct commit *preferred;
+
+ preferred = try_to_simplify_merge(commit, parent);
+ if (preferred) {
+ parent->item = preferred;
+ parent->next = NULL;
+ }
+ }
+
+ while (parent) {
+ struct commit *p = parent->item;
+
+ parent = parent->next;
+
+ parse_commit(p);
+ if (p->object.flags & SEEN)
+ continue;
+ p->object.flags |= SEEN;
+ insert_by_date(p, list);
+ }
+}
+
static struct commit_list *limit_list(struct commit_list *list)
{
struct commit_list *newlist = NULL;
struct commit_list **p = &newlist;
while (list) {
- struct commit *commit = pop_most_recent_commit(&list, SEEN);
+ struct commit_list *entry = list;
+ struct commit *commit = list->item;
struct object *obj = &commit->object;
+ list = list->next;
+ free(entry);
+
if (max_age != -1 && (commit->date < max_age))
obj->flags |= UNINTERESTING;
if (unpacked && has_sha1_pack(obj->sha1))
obj->flags |= UNINTERESTING;
+ add_parents_to_list(commit, &list);
if (obj->flags & UNINTERESTING) {
mark_parents_uninteresting(commit);
if (everybody_uninteresting(list))
@@ -507,15 +620,15 @@ static void handle_all(struct commit_list **lst)
global_lst = NULL;
}
-int main(int argc, char **argv)
+int main(int argc, const char **argv)
{
+ const char *prefix = setup_git_directory();
struct commit_list *list = NULL;
int i, limited = 0;
- setup_git_directory();
for (i = 1 ; i < argc; i++) {
int flags;
- char *arg = argv[i];
+ const char *arg = argv[i];
char *dotdot;
struct commit *commit;
@@ -587,6 +700,14 @@ int main(int argc, char **argv)
limited = 1;
continue;
}
+ if (!strcmp(arg, "--")) {
+ paths = get_pathspec(prefix, argv + i + 1);
+ if (paths) {
+ limited = 1;
+ diff_tree_setup_paths(paths);
+ }
+ break;
+ }
if (show_breaks && !merge_order)
usage(rev_list_usage);