read-tree: move merge functions to the library

This will allow merge-recursive to use the read-tree functionality
without exec()ing git-read-tree.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Johannes Schindelin 2006-07-30 20:26:15 +02:00 committed by Junio C Hamano
parent 16da134b1f
commit 076b0adcf9
3 changed files with 410 additions and 397 deletions

View File

@ -3,10 +3,8 @@
*
* Copyright (C) Linus Torvalds, 2005
*/
#define DBRT_DEBUG 1
#include "cache.h"
#include "object.h"
#include "tree.h"
#include "tree-walk.h"
@ -16,12 +14,6 @@
static struct object_list *trees = NULL;
static void reject_merge(struct cache_entry *ce)
{
die("Entry '%s' would be overwritten by merge. Cannot merge.",
ce->name);
}
static int list_tree(unsigned char *sha1)
{
struct tree *tree = parse_tree_indirect(sha1);
@ -31,394 +23,6 @@ static int list_tree(unsigned char *sha1)
return 0;
}
static int same(struct cache_entry *a, struct cache_entry *b)
{
if (!!a != !!b)
return 0;
if (!a && !b)
return 1;
return a->ce_mode == b->ce_mode &&
!memcmp(a->sha1, b->sha1, 20);
}
/*
* When a CE gets turned into an unmerged entry, we
* want it to be up-to-date
*/
static void verify_uptodate(struct cache_entry *ce,
struct unpack_trees_options *o)
{
struct stat st;
if (o->index_only || o->reset)
return;
if (!lstat(ce->name, &st)) {
unsigned changed = ce_match_stat(ce, &st, 1);
if (!changed)
return;
errno = 0;
}
if (o->reset) {
ce->ce_flags |= htons(CE_UPDATE);
return;
}
if (errno == ENOENT)
return;
die("Entry '%s' not uptodate. Cannot merge.", ce->name);
}
static void invalidate_ce_path(struct cache_entry *ce)
{
if (ce)
cache_tree_invalidate_path(active_cache_tree, ce->name);
}
/*
* We do not want to remove or overwrite a working tree file that
* is not tracked.
*/
static void verify_absent(const char *path, const char *action,
struct unpack_trees_options *o)
{
struct stat st;
if (o->index_only || o->reset || !o->update)
return;
if (!lstat(path, &st))
die("Untracked working tree file '%s' "
"would be %s by merge.", path, action);
}
static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
struct unpack_trees_options *o)
{
merge->ce_flags |= htons(CE_UPDATE);
if (old) {
/*
* See if we can re-use the old CE directly?
* That way we get the uptodate stat info.
*
* This also removes the UPDATE flag on
* a match.
*/
if (same(old, merge)) {
*merge = *old;
} else {
verify_uptodate(old, o);
invalidate_ce_path(old);
}
}
else {
verify_absent(merge->name, "overwritten", o);
invalidate_ce_path(merge);
}
merge->ce_flags &= ~htons(CE_STAGEMASK);
add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
return 1;
}
static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
struct unpack_trees_options *o)
{
if (old)
verify_uptodate(old, o);
else
verify_absent(ce->name, "removed", o);
ce->ce_mode = 0;
add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
invalidate_ce_path(ce);
return 1;
}
static int keep_entry(struct cache_entry *ce)
{
add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
return 1;
}
#if DBRT_DEBUG
static void show_stage_entry(FILE *o,
const char *label, const struct cache_entry *ce)
{
if (!ce)
fprintf(o, "%s (missing)\n", label);
else
fprintf(o, "%s%06o %s %d\t%s\n",
label,
ntohl(ce->ce_mode),
sha1_to_hex(ce->sha1),
ce_stage(ce),
ce->name);
}
#endif
static int threeway_merge(struct cache_entry **stages,
struct unpack_trees_options *o)
{
struct cache_entry *index;
struct cache_entry *head;
struct cache_entry *remote = stages[o->head_idx + 1];
int count;
int head_match = 0;
int remote_match = 0;
const char *path = NULL;
int df_conflict_head = 0;
int df_conflict_remote = 0;
int any_anc_missing = 0;
int no_anc_exists = 1;
int i;
for (i = 1; i < o->head_idx; i++) {
if (!stages[i])
any_anc_missing = 1;
else {
if (!path)
path = stages[i]->name;
no_anc_exists = 0;
}
}
index = stages[0];
head = stages[o->head_idx];
if (head == &o->df_conflict_entry) {
df_conflict_head = 1;
head = NULL;
}
if (remote == &o->df_conflict_entry) {
df_conflict_remote = 1;
remote = NULL;
}
if (!path && index)
path = index->name;
if (!path && head)
path = head->name;
if (!path && remote)
path = remote->name;
/* First, if there's a #16 situation, note that to prevent #13
* and #14.
*/
if (!same(remote, head)) {
for (i = 1; i < o->head_idx; i++) {
if (same(stages[i], head)) {
head_match = i;
}
if (same(stages[i], remote)) {
remote_match = i;
}
}
}
/* We start with cases where the index is allowed to match
* something other than the head: #14(ALT) and #2ALT, where it
* is permitted to match the result instead.
*/
/* #14, #14ALT, #2ALT */
if (remote && !df_conflict_head && head_match && !remote_match) {
if (index && !same(index, remote) && !same(index, head))
reject_merge(index);
return merged_entry(remote, index, o);
}
/*
* If we have an entry in the index cache, then we want to
* make sure that it matches head.
*/
if (index && !same(index, head)) {
reject_merge(index);
}
if (head) {
/* #5ALT, #15 */
if (same(head, remote))
return merged_entry(head, index, o);
/* #13, #3ALT */
if (!df_conflict_remote && remote_match && !head_match)
return merged_entry(head, index, o);
}
/* #1 */
if (!head && !remote && any_anc_missing)
return 0;
/* Under the new "aggressive" rule, we resolve mostly trivial
* cases that we historically had git-merge-one-file resolve.
*/
if (o->aggressive) {
int head_deleted = !head && !df_conflict_head;
int remote_deleted = !remote && !df_conflict_remote;
/*
* Deleted in both.
* Deleted in one and unchanged in the other.
*/
if ((head_deleted && remote_deleted) ||
(head_deleted && remote && remote_match) ||
(remote_deleted && head && head_match)) {
if (index)
return deleted_entry(index, index, o);
else if (path)
verify_absent(path, "removed", o);
return 0;
}
/*
* Added in both, identically.
*/
if (no_anc_exists && head && remote && same(head, remote))
return merged_entry(head, index, o);
}
/* Below are "no merge" cases, which require that the index be
* up-to-date to avoid the files getting overwritten with
* conflict resolution files.
*/
if (index) {
verify_uptodate(index, o);
}
else if (path)
verify_absent(path, "overwritten", o);
o->nontrivial_merge = 1;
/* #2, #3, #4, #6, #7, #9, #11. */
count = 0;
if (!head_match || !remote_match) {
for (i = 1; i < o->head_idx; i++) {
if (stages[i]) {
keep_entry(stages[i]);
count++;
break;
}
}
}
#if DBRT_DEBUG
else {
fprintf(stderr, "read-tree: warning #16 detected\n");
show_stage_entry(stderr, "head ", stages[head_match]);
show_stage_entry(stderr, "remote ", stages[remote_match]);
}
#endif
if (head) { count += keep_entry(head); }
if (remote) { count += keep_entry(remote); }
return count;
}
/*
* Two-way merge.
*
* The rule is to "carry forward" what is in the index without losing
* information across a "fast forward", favoring a successful merge
* over a merge failure when it makes sense. For details of the
* "carry forward" rule, please see <Documentation/git-read-tree.txt>.
*
*/
static int twoway_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *current = src[0];
struct cache_entry *oldtree = src[1], *newtree = src[2];
if (o->merge_size != 2)
return error("Cannot do a twoway merge of %d trees",
o->merge_size);
if (current) {
if ((!oldtree && !newtree) || /* 4 and 5 */
(!oldtree && newtree &&
same(current, newtree)) || /* 6 and 7 */
(oldtree && newtree &&
same(oldtree, newtree)) || /* 14 and 15 */
(oldtree && newtree &&
!same(oldtree, newtree) && /* 18 and 19*/
same(current, newtree))) {
return keep_entry(current);
}
else if (oldtree && !newtree && same(current, oldtree)) {
/* 10 or 11 */
return deleted_entry(oldtree, current, o);
}
else if (oldtree && newtree &&
same(current, oldtree) && !same(current, newtree)) {
/* 20 or 21 */
return merged_entry(newtree, current, o);
}
else {
/* all other failures */
if (oldtree)
reject_merge(oldtree);
if (current)
reject_merge(current);
if (newtree)
reject_merge(newtree);
return -1;
}
}
else if (newtree)
return merged_entry(newtree, current, o);
else
return deleted_entry(oldtree, current, o);
}
/*
* Bind merge.
*
* Keep the index entries at stage0, collapse stage1 but make sure
* stage0 does not have anything there.
*/
static int bind_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *old = src[0];
struct cache_entry *a = src[1];
if (o->merge_size != 1)
return error("Cannot do a bind merge of %d trees\n",
o->merge_size);
if (a && old)
die("Entry '%s' overlaps. Cannot bind.", a->name);
if (!a)
return keep_entry(old);
else
return merged_entry(a, NULL, o);
}
/*
* One-way merge.
*
* The rule is:
* - take the stat information from stage0, take the data from stage1
*/
static int oneway_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *old = src[0];
struct cache_entry *a = src[1];
if (o->merge_size != 1)
return error("Cannot do a oneway merge of %d trees",
o->merge_size);
if (!a)
return deleted_entry(old, old, o);
if (old && same(old, a)) {
if (o->reset) {
struct stat st;
if (lstat(old->name, &st) ||
ce_match_stat(old, &st, 1))
old->ce_flags |= htons(CE_UPDATE);
}
return keep_entry(old);
}
return merged_entry(a, old, o);
}
static int read_cache_unmerged(void)
{
int i;
@ -432,7 +36,7 @@ static int read_cache_unmerged(void)
if (ce_stage(ce)) {
if (last && !strcmp(ce->name, last->name))
continue;
invalidate_ce_path(ce);
cache_tree_invalidate_path(active_cache_tree, ce->name);
last = ce;
ce->ce_mode = 0;
ce->ce_flags &= ~htons(CE_STAGEMASK);

View File

@ -3,8 +3,11 @@
#include "cache.h"
#include "tree.h"
#include "tree-walk.h"
#include "cache-tree.h"
#include "unpack-trees.h"
#define DBRT_DEBUG 1
struct tree_entry_list {
struct tree_entry_list *next;
unsigned directory : 1;
@ -22,6 +25,9 @@ static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
struct tree_entry_list *ret = NULL;
struct tree_entry_list **list_p = &ret;
if (!tree->object.parsed)
parse_tree(tree);
desc.buf = tree->buffer;
desc.size = tree->size;
@ -368,12 +374,14 @@ int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
memset(&df_conflict_list, 0, sizeof(df_conflict_list));
df_conflict_list.next = &df_conflict_list;
memset(&state, 0, sizeof(state));
state.base_dir = "";
state.force = 1;
state.quiet = 1;
state.refresh_cache = 1;
o->merge_size = len;
memset(&df_conflict_entry, 0, sizeof(df_conflict_entry));
o->df_conflict_entry = &df_conflict_entry;
if (len) {
@ -393,3 +401,399 @@ int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
check_updates(active_cache, active_nr, o);
return 0;
}
/* Here come the merge functions */
static void reject_merge(struct cache_entry *ce)
{
die("Entry '%s' would be overwritten by merge. Cannot merge.",
ce->name);
}
static int same(struct cache_entry *a, struct cache_entry *b)
{
if (!!a != !!b)
return 0;
if (!a && !b)
return 1;
return a->ce_mode == b->ce_mode &&
!memcmp(a->sha1, b->sha1, 20);
}
/*
* When a CE gets turned into an unmerged entry, we
* want it to be up-to-date
*/
static void verify_uptodate(struct cache_entry *ce,
struct unpack_trees_options *o)
{
struct stat st;
if (o->index_only || o->reset)
return;
if (!lstat(ce->name, &st)) {
unsigned changed = ce_match_stat(ce, &st, 1);
if (!changed)
return;
errno = 0;
}
if (o->reset) {
ce->ce_flags |= htons(CE_UPDATE);
return;
}
if (errno == ENOENT)
return;
die("Entry '%s' not uptodate. Cannot merge.", ce->name);
}
static void invalidate_ce_path(struct cache_entry *ce)
{
if (ce)
cache_tree_invalidate_path(active_cache_tree, ce->name);
}
/*
* We do not want to remove or overwrite a working tree file that
* is not tracked.
*/
static void verify_absent(const char *path, const char *action,
struct unpack_trees_options *o)
{
struct stat st;
if (o->index_only || o->reset || !o->update)
return;
if (!lstat(path, &st))
die("Untracked working tree file '%s' "
"would be %s by merge.", path, action);
}
static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
struct unpack_trees_options *o)
{
merge->ce_flags |= htons(CE_UPDATE);
if (old) {
/*
* See if we can re-use the old CE directly?
* That way we get the uptodate stat info.
*
* This also removes the UPDATE flag on
* a match.
*/
if (same(old, merge)) {
*merge = *old;
} else {
verify_uptodate(old, o);
invalidate_ce_path(old);
}
}
else {
verify_absent(merge->name, "overwritten", o);
invalidate_ce_path(merge);
}
merge->ce_flags &= ~htons(CE_STAGEMASK);
add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
return 1;
}
static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
struct unpack_trees_options *o)
{
if (old)
verify_uptodate(old, o);
else
verify_absent(ce->name, "removed", o);
ce->ce_mode = 0;
add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
invalidate_ce_path(ce);
return 1;
}
static int keep_entry(struct cache_entry *ce)
{
add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
return 1;
}
#if DBRT_DEBUG
static void show_stage_entry(FILE *o,
const char *label, const struct cache_entry *ce)
{
if (!ce)
fprintf(o, "%s (missing)\n", label);
else
fprintf(o, "%s%06o %s %d\t%s\n",
label,
ntohl(ce->ce_mode),
sha1_to_hex(ce->sha1),
ce_stage(ce),
ce->name);
}
#endif
int threeway_merge(struct cache_entry **stages,
struct unpack_trees_options *o)
{
struct cache_entry *index;
struct cache_entry *head;
struct cache_entry *remote = stages[o->head_idx + 1];
int count;
int head_match = 0;
int remote_match = 0;
const char *path = NULL;
int df_conflict_head = 0;
int df_conflict_remote = 0;
int any_anc_missing = 0;
int no_anc_exists = 1;
int i;
for (i = 1; i < o->head_idx; i++) {
if (!stages[i])
any_anc_missing = 1;
else {
if (!path)
path = stages[i]->name;
no_anc_exists = 0;
}
}
index = stages[0];
head = stages[o->head_idx];
if (head == o->df_conflict_entry) {
df_conflict_head = 1;
head = NULL;
}
if (remote == o->df_conflict_entry) {
df_conflict_remote = 1;
remote = NULL;
}
if (!path && index)
path = index->name;
if (!path && head)
path = head->name;
if (!path && remote)
path = remote->name;
/* First, if there's a #16 situation, note that to prevent #13
* and #14.
*/
if (!same(remote, head)) {
for (i = 1; i < o->head_idx; i++) {
if (same(stages[i], head)) {
head_match = i;
}
if (same(stages[i], remote)) {
remote_match = i;
}
}
}
/* We start with cases where the index is allowed to match
* something other than the head: #14(ALT) and #2ALT, where it
* is permitted to match the result instead.
*/
/* #14, #14ALT, #2ALT */
if (remote && !df_conflict_head && head_match && !remote_match) {
if (index && !same(index, remote) && !same(index, head))
reject_merge(index);
return merged_entry(remote, index, o);
}
/*
* If we have an entry in the index cache, then we want to
* make sure that it matches head.
*/
if (index && !same(index, head)) {
reject_merge(index);
}
if (head) {
/* #5ALT, #15 */
if (same(head, remote))
return merged_entry(head, index, o);
/* #13, #3ALT */
if (!df_conflict_remote && remote_match && !head_match)
return merged_entry(head, index, o);
}
/* #1 */
if (!head && !remote && any_anc_missing)
return 0;
/* Under the new "aggressive" rule, we resolve mostly trivial
* cases that we historically had git-merge-one-file resolve.
*/
if (o->aggressive) {
int head_deleted = !head && !df_conflict_head;
int remote_deleted = !remote && !df_conflict_remote;
/*
* Deleted in both.
* Deleted in one and unchanged in the other.
*/
if ((head_deleted && remote_deleted) ||
(head_deleted && remote && remote_match) ||
(remote_deleted && head && head_match)) {
if (index)
return deleted_entry(index, index, o);
else if (path)
verify_absent(path, "removed", o);
return 0;
}
/*
* Added in both, identically.
*/
if (no_anc_exists && head && remote && same(head, remote))
return merged_entry(head, index, o);
}
/* Below are "no merge" cases, which require that the index be
* up-to-date to avoid the files getting overwritten with
* conflict resolution files.
*/
if (index) {
verify_uptodate(index, o);
}
else if (path)
verify_absent(path, "overwritten", o);
o->nontrivial_merge = 1;
/* #2, #3, #4, #6, #7, #9, #11. */
count = 0;
if (!head_match || !remote_match) {
for (i = 1; i < o->head_idx; i++) {
if (stages[i]) {
keep_entry(stages[i]);
count++;
break;
}
}
}
#if DBRT_DEBUG
else {
fprintf(stderr, "read-tree: warning #16 detected\n");
show_stage_entry(stderr, "head ", stages[head_match]);
show_stage_entry(stderr, "remote ", stages[remote_match]);
}
#endif
if (head) { count += keep_entry(head); }
if (remote) { count += keep_entry(remote); }
return count;
}
/*
* Two-way merge.
*
* The rule is to "carry forward" what is in the index without losing
* information across a "fast forward", favoring a successful merge
* over a merge failure when it makes sense. For details of the
* "carry forward" rule, please see <Documentation/git-read-tree.txt>.
*
*/
int twoway_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *current = src[0];
struct cache_entry *oldtree = src[1], *newtree = src[2];
if (o->merge_size != 2)
return error("Cannot do a twoway merge of %d trees",
o->merge_size);
if (current) {
if ((!oldtree && !newtree) || /* 4 and 5 */
(!oldtree && newtree &&
same(current, newtree)) || /* 6 and 7 */
(oldtree && newtree &&
same(oldtree, newtree)) || /* 14 and 15 */
(oldtree && newtree &&
!same(oldtree, newtree) && /* 18 and 19*/
same(current, newtree))) {
return keep_entry(current);
}
else if (oldtree && !newtree && same(current, oldtree)) {
/* 10 or 11 */
return deleted_entry(oldtree, current, o);
}
else if (oldtree && newtree &&
same(current, oldtree) && !same(current, newtree)) {
/* 20 or 21 */
return merged_entry(newtree, current, o);
}
else {
/* all other failures */
if (oldtree)
reject_merge(oldtree);
if (current)
reject_merge(current);
if (newtree)
reject_merge(newtree);
return -1;
}
}
else if (newtree)
return merged_entry(newtree, current, o);
else
return deleted_entry(oldtree, current, o);
}
/*
* Bind merge.
*
* Keep the index entries at stage0, collapse stage1 but make sure
* stage0 does not have anything there.
*/
int bind_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *old = src[0];
struct cache_entry *a = src[1];
if (o->merge_size != 1)
return error("Cannot do a bind merge of %d trees\n",
o->merge_size);
if (a && old)
die("Entry '%s' overlaps. Cannot bind.", a->name);
if (!a)
return keep_entry(old);
else
return merged_entry(a, NULL, o);
}
/*
* One-way merge.
*
* The rule is:
* - take the stat information from stage0, take the data from stage1
*/
int oneway_merge(struct cache_entry **src,
struct unpack_trees_options *o)
{
struct cache_entry *old = src[0];
struct cache_entry *a = src[1];
if (o->merge_size != 1)
return error("Cannot do a oneway merge of %d trees",
o->merge_size);
if (!a)
return deleted_entry(old, old, o);
if (old && same(old, a)) {
if (o->reset) {
struct stat st;
if (lstat(old->name, &st) ||
ce_match_stat(old, &st, 1))
old->ce_flags |= htons(CE_UPDATE);
}
return keep_entry(old);
}
return merged_entry(a, old, o);
}

View File

@ -27,4 +27,9 @@ struct unpack_trees_options {
extern int unpack_trees(struct object_list *trees,
struct unpack_trees_options *options);
int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o);
int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o);
int bind_merge(struct cache_entry **src, struct unpack_trees_options *o);
int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o);
#endif