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-rw-r--r--read-tree.c603
1 files changed, 0 insertions, 603 deletions
diff --git a/read-tree.c b/read-tree.c
deleted file mode 100644
index ce2bb88f0a..0000000000
--- a/read-tree.c
+++ /dev/null
@@ -1,603 +0,0 @@
-/*
- * GIT - The information manager from hell
- *
- * Copyright (C) Linus Torvalds, 2005
- */
-#include "cache.h"
-
-static int stage = 0;
-static int update = 0;
-
-static int unpack_tree(unsigned char *sha1)
-{
- void *buffer;
- unsigned long size;
- int ret;
-
- buffer = read_object_with_reference(sha1, "tree", &size, NULL);
- if (!buffer)
- return -1;
- ret = read_tree(buffer, size, stage, NULL);
- free(buffer);
- return ret;
-}
-
-static int path_matches(struct cache_entry *a, struct cache_entry *b)
-{
- int len = ce_namelen(a);
- return ce_namelen(b) == len &&
- !memcmp(a->name, b->name, len);
-}
-
-static int same(struct cache_entry *a, struct cache_entry *b)
-{
- return a->ce_mode == b->ce_mode &&
- !memcmp(a->sha1, b->sha1, 20);
-}
-
-
-/*
- * This removes all trivial merges that don't change the tree
- * and collapses them to state 0.
- */
-static struct cache_entry *merge_entries(struct cache_entry *a,
- struct cache_entry *b,
- struct cache_entry *c)
-{
- /*
- * Ok, all three entries describe the same
- * filename, but maybe the contents or file
- * mode have changed?
- *
- * The trivial cases end up being the ones where two
- * out of three files are the same:
- * - both destinations the same, trivially take either
- * - one of the destination versions hasn't changed,
- * take the other.
- *
- * The "all entries exactly the same" case falls out as
- * a special case of any of the "two same" cases.
- *
- * Here "a" is "original", and "b" and "c" are the two
- * trees we are merging.
- */
- if (a && b && c) {
- if (same(b,c))
- return c;
- if (same(a,b))
- return c;
- if (same(a,c))
- return b;
- }
- return NULL;
-}
-
-/*
- * 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 stat st;
-
- if (!lstat(ce->name, &st)) {
- unsigned changed = ce_match_stat(ce, &st);
- if (!changed)
- return;
- errno = 0;
- }
- if (errno == ENOENT)
- return;
- die("Entry '%s' not uptodate. Cannot merge.", ce->name);
-}
-
-/*
- * If the old tree contained a CE that isn't even in the
- * result, that's always a problem, regardless of whether
- * it's up-to-date or not (ie it can be a file that we
- * have updated but not committed yet).
- */
-static void reject_merge(struct cache_entry *ce)
-{
- die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
-}
-
-static int merged_entry_internal(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst, int allow_dirty)
-{
- 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 if (!allow_dirty) {
- verify_uptodate(old);
- }
- }
- merge->ce_flags &= ~htons(CE_STAGEMASK);
- *dst++ = merge;
- return 1;
-}
-
-static int merged_entry_allow_dirty(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
-{
- return merged_entry_internal(merge, old, dst, 1);
-}
-
-static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
-{
- return merged_entry_internal(merge, old, dst, 0);
-}
-
-static int deleted_entry(struct cache_entry *ce, struct cache_entry *old, struct cache_entry **dst)
-{
- if (old)
- verify_uptodate(old);
- ce->ce_mode = 0;
- *dst++ = ce;
- return 1;
-}
-
-static int causes_df_conflict(struct cache_entry *ce, int stage,
- struct cache_entry **dst_,
- struct cache_entry **next_,
- int tail)
-{
- /* This is called during the merge operation and walking
- * the active_cache[] array is messy, because it is in the
- * middle of overlapping copy operation. The invariants
- * are:
- * (1) active_cache points at the first (zeroth) entry.
- * (2) up to dst pointer are resolved entries.
- * (3) from the next pointer (head-inclusive) to the tail
- * of the active_cache array have the remaining paths
- * to be processed. There can be a gap between dst
- * and next. Note that next is called "src" in the
- * merge_cache() function, and tail is the original
- * end of active_cache array when merge_cache() started.
- * (4) the path corresponding to *ce is not found in (2)
- * or (3). It is in the gap.
- *
- * active_cache -----......+++++++++++++.
- * ^dst ^next ^tail
- */
- int i, next, dst;
- const char *path = ce->name;
- int namelen = ce_namelen(ce);
-
- next = next_ - active_cache;
- dst = dst_ - active_cache;
-
- for (i = 0; i < tail; i++) {
- int entlen, len;
- const char *one, *two;
- if (dst <= i && i < next)
- continue;
- ce = active_cache[i];
- if (ce_stage(ce) != stage)
- continue;
- /* If ce->name is a prefix of path, then path is a file
- * that hangs underneath ce->name, which is bad.
- * If path is a prefix of ce->name, then it is the
- * other way around which also is bad.
- */
- entlen = ce_namelen(ce);
- if (namelen == entlen)
- continue;
- if (namelen < entlen) {
- len = namelen;
- one = path;
- two = ce->name;
- } else {
- len = entlen;
- one = ce->name;
- two = path;
- }
- if (memcmp(one, two, len))
- continue;
- if (two[len] == '/')
- return 1;
- }
- return 0;
-}
-
-static int threeway_merge(struct cache_entry *stages[4],
- struct cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *old = stages[0];
- struct cache_entry *a = stages[1], *b = stages[2], *c = stages[3];
- struct cache_entry *merge;
- int count;
-
- /* #5ALT */
- if (!a && b && c && same(b, c)) {
- if (old && !same(b, old))
- return -1;
- return merged_entry_allow_dirty(b, old, dst);
- }
- /* #2ALT and #3ALT */
- if (!a && (!!b != !!c)) {
- /*
- * The reason we need to worry about directory/file
- * conflicts only in #2ALT and #3ALT case is this:
- *
- * (1) For all other cases that read-tree internally
- * resolves a path, we always have such a path in
- * *both* stage2 and stage3 when we begin.
- * Traditionally, the behaviour has been even
- * stricter and we did not resolve a path without
- * initially being in all of stage1, 2, and 3.
- *
- * (2) When read-tree finishes, all resolved paths (i.e.
- * the paths that are in stage0) must have come from
- * either stage2 or stage3. It is not possible to
- * have a stage0 path as a result of a merge if
- * neither stage2 nor stage3 had that path.
- *
- * (3) It is guaranteed that just after reading the
- * stages, each stage cannot have directory/file
- * conflicts on its own, because they are populated
- * by reading hierarchy of a tree. Combined with
- * (1) and (2) above, this means that no matter what
- * combination of paths we take from stage2 and
- * stage3 as a result of a merge, they cannot cause
- * a directory/file conflict situation (otherwise
- * the "guilty" path would have already had such a
- * conflict in the original stage, either stage2
- * or stage3). Although its stage2 is synthesized
- * by overlaying the current index on top of "our
- * head" tree, --emu23 case also has this guarantee,
- * by calling add_cache_entry() to create such stage2
- * entries.
- *
- * (4) Only #2ALT and #3ALT lack the guarantee (1).
- * They resolve paths that exist only in stage2
- * or stage3. The stage2 tree may have a file DF
- * while stage3 tree may have a file DF/DF. If
- * #2ALT and #3ALT rules happen to apply to both
- * of them, we would end up having DF (coming from
- * stage2) and DF/DF (from stage3) in the result.
- * When we attempt to resolve a path that exists
- * only in stage2, we need to make sure there is
- * no path that would conflict with it in stage3
- * and vice versa.
- */
- if (c) { /* #2ALT */
- if (!causes_df_conflict(c, 2, dst, next, tail) &&
- (!old || same(c, old)))
- return merged_entry_allow_dirty(c, old, dst);
- }
- else { /* #3ALT */
- if (!causes_df_conflict(b, 3, dst, next, tail) &&
- (!old || same(b, old)))
- return merged_entry_allow_dirty(b, old, dst);
- }
- /* otherwise we will apply the original rule */
- }
- /* #14ALT */
- if (a && b && c && same(a, b) && !same(a, c)) {
- if (old && same(old, c))
- return merged_entry_allow_dirty(c, old, dst);
- /* otherwise the regular rule applies */
- }
- /*
- * If we have an entry in the index cache ("old"), then we want
- * to make sure that it matches any entries in stage 2 ("first
- * branch", aka "b").
- */
- if (old) {
- if (!b || !same(old, b))
- return -1;
- }
- merge = merge_entries(a, b, c);
- if (merge)
- return merged_entry(merge, old, dst);
- if (old)
- verify_uptodate(old);
- count = 0;
- if (a) { *dst++ = a; count++; }
- if (b) { *dst++ = b; count++; }
- if (c) { *dst++ = c; count++; }
- 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 cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *current = src[0];
- struct cache_entry *oldtree = src[1], *newtree = src[2];
-
- if (src[3])
- return -1;
-
- 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))) {
- *dst++ = current;
- return 1;
- }
- else if (oldtree && !newtree && same(current, oldtree)) {
- /* 10 or 11 */
- return deleted_entry(oldtree, current, dst);
- }
- else if (oldtree && newtree &&
- same(current, oldtree) && !same(current, newtree)) {
- /* 20 or 21 */
- return merged_entry(newtree, current, dst);
- }
- else
- /* all other failures */
- return -1;
- }
- else if (newtree)
- return merged_entry(newtree, current, dst);
- else
- return deleted_entry(oldtree, current, dst);
-}
-
-/*
- * Two-way merge emulated with three-way merge.
- *
- * This treats "read-tree -m H M" by transforming it internally
- * into "read-tree -m H I+H M", where I+H is a tree that would
- * contain the contents of the current index file, overlayed on
- * top of H. Unlike the traditional two-way merge, this leaves
- * the stages in the resulting index file and lets the user resolve
- * the merge conflicts using standard tools for three-way merge.
- *
- * This function is just to set-up such an arrangement, and the
- * actual merge uses threeway_merge() function.
- */
-static void setup_emu23(void)
-{
- /* stage0 contains I, stage1 H, stage2 M.
- * move stage2 to stage3, and create stage2 entries
- * by scanning stage0 and stage1 entries.
- */
- int i, namelen, size;
- struct cache_entry *ce, *stage2;
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) != 2)
- continue;
- /* hoist them up to stage 3 */
- namelen = ce_namelen(ce);
- ce->ce_flags = create_ce_flags(namelen, 3);
- }
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) > 1)
- continue;
- namelen = ce_namelen(ce);
- size = cache_entry_size(namelen);
- stage2 = xmalloc(size);
- memcpy(stage2, ce, size);
- stage2->ce_flags = create_ce_flags(namelen, 2);
- if (add_cache_entry(stage2, ADD_CACHE_OK_TO_ADD) < 0)
- die("cannot merge index and our head tree");
-
- /* We are done with this name, so skip to next name */
- while (i < active_nr &&
- ce_namelen(active_cache[i]) == namelen &&
- !memcmp(active_cache[i]->name, ce->name, namelen))
- i++;
- i--; /* compensate for the loop control */
- }
-}
-
-/*
- * 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 cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *old = src[0];
- struct cache_entry *a = src[1];
-
- if (src[2] || src[3])
- return -1;
-
- if (!a)
- return 0;
- if (old && same(old, a)) {
- *dst++ = old;
- return 1;
- }
- return merged_entry(a, NULL, dst);
-}
-
-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_mode) {
- if (update)
- unlink(ce->name);
- continue;
- }
- if (ce->ce_flags & mask) {
- ce->ce_flags &= ~mask;
- if (update)
- checkout_entry(ce, &state);
- }
- }
-}
-
-typedef int (*merge_fn_t)(struct cache_entry **, struct cache_entry **, struct cache_entry **, int);
-
-static void merge_cache(struct cache_entry **src, int nr, merge_fn_t fn)
-{
- struct cache_entry **dst = src;
- int tail = nr;
-
- while (nr) {
- int entries;
- struct cache_entry *name, *ce, *stages[4] = { NULL, };
-
- name = ce = *src;
- for (;;) {
- int stage = ce_stage(ce);
- stages[stage] = ce;
- ce = *++src;
- active_nr--;
- if (!--nr)
- break;
- if (!path_matches(ce, name))
- break;
- }
-
- entries = fn(stages, dst, src, tail);
- if (entries < 0)
- reject_merge(name);
- dst += entries;
- active_nr += entries;
- }
- check_updates(active_cache, active_nr);
-}
-
-static int read_cache_unmerged(void)
-{
- int i, deleted;
- struct cache_entry **dst;
-
- read_cache();
- dst = active_cache;
- deleted = 0;
- for (i = 0; i < active_nr; i++) {
- struct cache_entry *ce = active_cache[i];
- if (ce_stage(ce)) {
- deleted++;
- continue;
- }
- if (deleted)
- *dst = ce;
- dst++;
- }
- active_nr -= deleted;
- return deleted;
-}
-
-static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
-
-static struct cache_file cache_file;
-
-int main(int argc, char **argv)
-{
- int i, newfd, merge, reset, emu23;
- unsigned char sha1[20];
-
- newfd = hold_index_file_for_update(&cache_file, get_index_file());
- if (newfd < 0)
- die("unable to create new cachefile");
-
- merge = 0;
- reset = 0;
- emu23 = 0;
- 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;
- }
-
- /* This differs from "-m" in that we'll silently ignore unmerged entries */
- if (!strcmp(arg, "--reset")) {
- if (stage || merge || emu23)
- usage(read_tree_usage);
- reset = 1;
- merge = 1;
- stage = 1;
- read_cache_unmerged();
- continue;
- }
-
- /* "-m" stands for "merge", meaning we start in stage 1 */
- if (!strcmp(arg, "-m")) {
- if (stage || merge || emu23)
- usage(read_tree_usage);
- if (read_cache_unmerged())
- die("you need to resolve your current index first");
- stage = 1;
- merge = 1;
- continue;
- }
-
- /* "-emu23" uses 3-way merge logic to perform fast-forward */
- if (!strcmp(arg, "--emu23")) {
- if (stage || merge || emu23)
- usage(read_tree_usage);
- if (read_cache_unmerged())
- die("you need to resolve your current index first");
- merge = emu23 = stage = 1;
- continue;
- }
-
- if (get_sha1(arg, sha1) < 0)
- usage(read_tree_usage);
- if (stage > 3)
- usage(read_tree_usage);
- if (unpack_tree(sha1) < 0)
- die("failed to unpack tree object %s", arg);
- stage++;
- }
- if (update && !merge)
- usage(read_tree_usage);
- if (merge) {
- static const merge_fn_t merge_function[] = {
- [1] = oneway_merge,
- [2] = twoway_merge,
- [3] = threeway_merge,
- };
- merge_fn_t fn;
-
- if (stage < 2 || stage > 4)
- die("just how do you expect me to merge %d trees?", stage-1);
- if (emu23 && stage != 3)
- die("--emu23 takes only two trees");
- fn = merge_function[stage-1];
- if (stage == 3 && emu23) {
- setup_emu23();
- fn = merge_function[3];
- }
- merge_cache(active_cache, active_nr, fn);
- }
- if (write_cache(newfd, active_cache, active_nr) ||
- commit_index_file(&cache_file))
- die("unable to write new index file");
- return 0;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 07:32:47 +0000