From 220a0b527bd6ecd30a9d6dfed22195c95e6f445a Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 5 Jun 2005 22:07:31 -0700 Subject: [PATCH] More work on merging with git-read-tree.. Add a "-u" flag to update the tree as a result of a merge. Right now this code is way too anal about things, and fails merges it shouldn't, but let me fix up the different cases and this will allow for much smoother merging even in the presense of dirty data in the working tree. --- cache.h | 1 + git-resolve-script | 6 +-- read-tree.c | 123 ++++++++++++++++++++++++++++++++++++++------- 3 files changed, 107 insertions(+), 23 deletions(-) diff --git a/cache.h b/cache.h index 7cb5b554b..aa901d1f4 100644 --- a/cache.h +++ b/cache.h @@ -84,6 +84,7 @@ struct cache_entry { #define CE_NAMEMASK (0x0fff) #define CE_STAGEMASK (0x3000) +#define CE_UPDATE (0x4000) #define CE_STAGESHIFT 12 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT)) diff --git a/git-resolve-script b/git-resolve-script index 4fc7a6dce..186b234b2 100644 --- a/git-resolve-script +++ b/git-resolve-script @@ -39,14 +39,13 @@ if [ "$common" == "$head" ]; then echo "Destroying all noncommitted data!" echo "Kill me within 3 seconds.." sleep 3 - git-read-tree -m $merge || exit 1 - git-checkout-cache -f -u -a + git-read-tree -u -m $head $merge || exit 1 echo $merge > "$GIT_DIR"/HEAD git-diff-tree -p ORIG_HEAD HEAD | git-apply --stat exit 0 fi echo "Trying to merge $merge into $head" -git-read-tree -m $common $head $merge || exit 1 +git-read-tree -u -m $common $head $merge || exit 1 merge_msg="Merge of $merge_repo" result_tree=$(git-write-tree 2> /dev/null) if [ $? -ne 0 ]; then @@ -58,5 +57,4 @@ fi result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree -p $head -p $merge) echo "Committed merge $result_commit" echo $result_commit > "$GIT_DIR"/HEAD -git-checkout-cache -f -u -a git-diff-tree -p ORIG_HEAD HEAD | git-apply --stat diff --git a/read-tree.c b/read-tree.c index 374698412..1a575eb0d 100644 --- a/read-tree.c +++ b/read-tree.c @@ -6,6 +6,7 @@ #include "cache.h" static int stage = 0; +static int update = 0; static int unpack_tree(unsigned char *sha1) { @@ -130,27 +131,29 @@ static void trivially_merge_cache(struct cache_entry **src, int nr) struct cache_entry **dst = src; struct cache_entry *old = NULL; - while (nr) { + while (nr--) { struct cache_entry *ce, *result; - ce = src[0]; + ce = *src++; /* We throw away original cache entries except for the stat information */ if (!ce_stage(ce)) { if (old) reject_merge(old); old = ce; - src++; - nr--; active_nr--; continue; } if (old && !path_matches(old, ce)) reject_merge(old); if (nr > 2 && (result = merge_entries(ce, src[1], src[2])) != NULL) { + result->ce_flags |= htons(CE_UPDATE); /* * 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 (old && same(old, result)) { *result = *old; @@ -172,42 +175,113 @@ static void trivially_merge_cache(struct cache_entry **src, int nr) */ CHECK_OLD(ce); *dst++ = ce; - src++; - nr--; } if (old) reject_merge(old); } -static void merge_stat_info(struct cache_entry **src, int nr) +/* + * Two-way merge. + * + * The rule is: + * - every current entry has to match the old tree + * - if the current entry matches the new tree, we leave it + * as-is. Otherwise we require that it be up-to-date. + */ +static void twoway_merge(struct cache_entry **src, int nr) { static struct cache_entry null_entry; + struct cache_entry *old = NULL, *stat = &null_entry; struct cache_entry **dst = src; - struct cache_entry *old = &null_entry; - while (nr) { - struct cache_entry *ce; + while (nr--) { + struct cache_entry *ce = *src++; + int stage = ce_stage(ce); + + switch (stage) { + case 0: + if (old) + reject_merge(old); + old = ce; + stat = ce; + active_nr--; + continue; + + case 1: + active_nr--; + if (!old) + continue; + if (!path_matches(old, ce) || !same(old, ce)) + reject_merge(old); + continue; + + case 2: + ce->ce_flags |= htons(CE_UPDATE); + if (old) { + if (!path_matches(old, ce)) + reject_merge(old); + /* + * This also removes the UPDATE flag on + * a match + */ + if (same(old, ce)) + *ce = *old; + else + verify_uptodate(old); + old = NULL; + } + ce->ce_flags &= ~htons(CE_STAGEMASK); + *dst++ = ce; + continue; + } + die("impossible two-way stage"); + } + if (old) + reject_merge(old); +} + +static void merge_stat_info(struct cache_entry **src, int nr) +{ + static struct cache_entry null_entry; + struct cache_entry **dst = src; + struct cache_entry *stat = &null_entry; - ce = src[0]; + while (nr--) { + struct cache_entry *ce = *src++; /* We throw away original cache entries except for the stat information */ if (!ce_stage(ce)) { - old = ce; - src++; - nr--; + stat = ce; active_nr--; continue; } - if (path_matches(ce, old) && same(ce, old)) - *ce = *old; + if (path_matches(ce, stat) && same(ce, stat)) + *ce = *stat; ce->ce_flags &= ~htons(CE_STAGEMASK); *dst++ = ce; - src++; - nr--; } } -static char *read_tree_usage = "git-read-tree ( | -m [ ])"; +static void check_updates(struct cache_entry **src, int nr) +{ + static struct checkout state = { + .base_dir = "", + .force = 1, + .quiet = 1, + .refresh_cache = 1, + }; + unsigned short mask = htons(CE_UPDATE); + while (nr--) { + struct cache_entry *ce = *src++; + if (ce->ce_flags & mask) { + ce->ce_flags &= ~mask; + if (update) + checkout_entry(ce, &state); + } + } +} + +static char *read_tree_usage = "git-read-tree ( | -m [ []])"; int main(int argc, char **argv) { @@ -228,6 +302,12 @@ int main(int argc, char **argv) for (i = 1; i < argc; i++) { const char *arg = argv[i]; + /* "-u" means "update", meaning that a merge will update the working directory */ + if (!strcmp(arg, "-u")) { + update = 1; + continue; + } + /* "-m" stands for "merge", meaning we start in stage 1 */ if (!strcmp(arg, "-m")) { int i; @@ -254,6 +334,11 @@ int main(int argc, char **argv) switch (stage) { case 4: /* Three-way merge */ trivially_merge_cache(active_cache, active_nr); + check_updates(active_cache, active_nr); + break; + case 3: /* Update from one tree to another */ + twoway_merge(active_cache, active_nr); + check_updates(active_cache, active_nr); break; case 2: /* Just read a tree, merge with old cache contents */ merge_stat_info(active_cache, active_nr); -- 2.26.2