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7e4a2a8483
Avoid asking for zero bytes when that change simplifies overall logic. Later we would change the wrapper to ask for 1 byte on platforms that return NULL for zero byte request. Signed-off-by: Junio C Hamano <junkio@cox.net>
734 lines
16 KiB
C
734 lines
16 KiB
C
/*
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* GIT - The information manager from hell
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*
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* Copyright (C) Linus Torvalds, 2005
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*/
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#define DBRT_DEBUG 1
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#include "cache.h"
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#include "object.h"
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#include "tree.h"
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static int merge = 0;
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static int update = 0;
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static int index_only = 0;
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static int nontrivial_merge = 0;
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static int trivial_merges_only = 0;
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static int head_idx = -1;
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static int merge_size = 0;
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static struct object_list *trees = NULL;
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static struct cache_entry df_conflict_entry = {
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};
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static struct tree_entry_list df_conflict_list = {
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.name = NULL,
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.next = &df_conflict_list
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};
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typedef int (*merge_fn_t)(struct cache_entry **src);
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static int entcmp(char *name1, int dir1, char *name2, int dir2)
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{
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int len1 = strlen(name1);
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int len2 = strlen(name2);
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int len = len1 < len2 ? len1 : len2;
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int ret = memcmp(name1, name2, len);
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unsigned char c1, c2;
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if (ret)
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return ret;
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c1 = name1[len];
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c2 = name2[len];
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if (!c1 && dir1)
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c1 = '/';
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if (!c2 && dir2)
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c2 = '/';
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ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
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if (c1 && c2 && !ret)
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ret = len1 - len2;
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return ret;
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}
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static int unpack_trees_rec(struct tree_entry_list **posns, int len,
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const char *base, merge_fn_t fn, int *indpos)
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{
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int baselen = strlen(base);
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int src_size = len + 1;
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do {
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int i;
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char *first;
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int firstdir = 0;
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int pathlen;
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unsigned ce_size;
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struct tree_entry_list **subposns;
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struct cache_entry **src;
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int any_files = 0;
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int any_dirs = 0;
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char *cache_name;
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int ce_stage;
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/* Find the first name in the input. */
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first = NULL;
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cache_name = NULL;
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/* Check the cache */
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if (merge && *indpos < active_nr) {
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/* This is a bit tricky: */
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/* If the index has a subdirectory (with
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* contents) as the first name, it'll get a
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* filename like "foo/bar". But that's after
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* "foo", so the entry in trees will get
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* handled first, at which point we'll go into
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* "foo", and deal with "bar" from the index,
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* because the base will be "foo/". The only
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* way we can actually have "foo/bar" first of
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* all the things is if the trees don't
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* contain "foo" at all, in which case we'll
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* handle "foo/bar" without going into the
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* directory, but that's fine (and will return
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* an error anyway, with the added unknown
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* file case.
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*/
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cache_name = active_cache[*indpos]->name;
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if (strlen(cache_name) > baselen &&
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!memcmp(cache_name, base, baselen)) {
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cache_name += baselen;
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first = cache_name;
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} else {
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cache_name = NULL;
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}
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}
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#if DBRT_DEBUG > 1
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if (first)
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printf("index %s\n", first);
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#endif
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for (i = 0; i < len; i++) {
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if (!posns[i] || posns[i] == &df_conflict_list)
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continue;
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#if DBRT_DEBUG > 1
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printf("%d %s\n", i + 1, posns[i]->name);
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#endif
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if (!first || entcmp(first, firstdir,
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posns[i]->name,
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posns[i]->directory) > 0) {
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first = posns[i]->name;
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firstdir = posns[i]->directory;
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}
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}
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/* No name means we're done */
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if (!first)
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return 0;
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pathlen = strlen(first);
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ce_size = cache_entry_size(baselen + pathlen);
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src = xmalloc(sizeof(struct cache_entry *) * src_size);
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memset(src, 0, sizeof(struct cache_entry *) * src_size);
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subposns = xmalloc(sizeof(struct tree_list_entry *) * len);
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memset(subposns, 0, sizeof(struct tree_list_entry *) * len);
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if (cache_name && !strcmp(cache_name, first)) {
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any_files = 1;
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src[0] = active_cache[*indpos];
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remove_cache_entry_at(*indpos);
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}
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for (i = 0; i < len; i++) {
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struct cache_entry *ce;
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if (!posns[i] ||
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(posns[i] != &df_conflict_list &&
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strcmp(first, posns[i]->name))) {
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continue;
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}
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if (posns[i] == &df_conflict_list) {
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src[i + merge] = &df_conflict_entry;
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continue;
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}
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if (posns[i]->directory) {
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any_dirs = 1;
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parse_tree(posns[i]->item.tree);
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subposns[i] = posns[i]->item.tree->entries;
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posns[i] = posns[i]->next;
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src[i + merge] = &df_conflict_entry;
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continue;
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}
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if (!merge)
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ce_stage = 0;
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else if (i + 1 < head_idx)
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ce_stage = 1;
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else if (i + 1 > head_idx)
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ce_stage = 3;
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else
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ce_stage = 2;
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ce = xmalloc(ce_size);
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memset(ce, 0, ce_size);
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ce->ce_mode = create_ce_mode(posns[i]->mode);
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ce->ce_flags = create_ce_flags(baselen + pathlen,
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ce_stage);
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memcpy(ce->name, base, baselen);
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memcpy(ce->name + baselen, first, pathlen + 1);
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any_files = 1;
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memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
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src[i + merge] = ce;
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subposns[i] = &df_conflict_list;
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posns[i] = posns[i]->next;
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}
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if (any_files) {
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if (merge) {
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int ret;
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#if DBRT_DEBUG > 1
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printf("%s:\n", first);
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for (i = 0; i < src_size; i++) {
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printf(" %d ", i);
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if (src[i])
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printf("%s\n", sha1_to_hex(src[i]->sha1));
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else
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printf("\n");
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}
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#endif
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ret = fn(src);
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#if DBRT_DEBUG > 1
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printf("Added %d entries\n", ret);
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#endif
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*indpos += ret;
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} else {
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for (i = 0; i < src_size; i++) {
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if (src[i]) {
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add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
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}
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}
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}
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}
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if (any_dirs) {
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char *newbase = xmalloc(baselen + 2 + pathlen);
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memcpy(newbase, base, baselen);
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memcpy(newbase + baselen, first, pathlen);
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newbase[baselen + pathlen] = '/';
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newbase[baselen + pathlen + 1] = '\0';
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if (unpack_trees_rec(subposns, len, newbase, fn,
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indpos))
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return -1;
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free(newbase);
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}
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free(subposns);
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free(src);
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} while (1);
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}
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static void reject_merge(struct cache_entry *ce)
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{
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die("Entry '%s' would be overwritten by merge. Cannot merge.",
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ce->name);
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}
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/* Unlink the last component and attempt to remove leading
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* directories, in case this unlink is the removal of the
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* last entry in the directory -- empty directories are removed.
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*/
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static void unlink_entry(char *name)
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{
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char *cp, *prev;
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if (unlink(name))
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return;
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prev = NULL;
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while (1) {
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int status;
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cp = strrchr(name, '/');
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if (prev)
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*prev = '/';
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if (!cp)
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break;
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*cp = 0;
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status = rmdir(name);
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if (status) {
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*cp = '/';
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break;
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}
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prev = cp;
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}
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}
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static void check_updates(struct cache_entry **src, int nr)
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{
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static struct checkout state = {
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.base_dir = "",
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.force = 1,
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.quiet = 1,
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.refresh_cache = 1,
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};
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unsigned short mask = htons(CE_UPDATE);
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while (nr--) {
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struct cache_entry *ce = *src++;
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if (!ce->ce_mode) {
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if (update)
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unlink_entry(ce->name);
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continue;
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}
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if (ce->ce_flags & mask) {
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ce->ce_flags &= ~mask;
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if (update)
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checkout_entry(ce, &state);
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}
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}
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}
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static int unpack_trees(merge_fn_t fn)
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{
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int indpos = 0;
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unsigned len = object_list_length(trees);
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struct tree_entry_list **posns;
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int i;
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struct object_list *posn = trees;
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merge_size = len;
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if (len) {
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posns = xmalloc(len * sizeof(struct tree_entry_list *));
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for (i = 0; i < len; i++) {
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posns[i] = ((struct tree *) posn->item)->entries;
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posn = posn->next;
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}
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if (unpack_trees_rec(posns, len, "", fn, &indpos))
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return -1;
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}
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if (trivial_merges_only && nontrivial_merge)
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die("Merge requires file-level merging");
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check_updates(active_cache, active_nr);
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return 0;
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}
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static int list_tree(unsigned char *sha1)
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{
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struct tree *tree = parse_tree_indirect(sha1);
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if (!tree)
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return -1;
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object_list_append(&tree->object, &trees);
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return 0;
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}
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static int same(struct cache_entry *a, struct cache_entry *b)
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{
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if (!!a != !!b)
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return 0;
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if (!a && !b)
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return 1;
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return a->ce_mode == b->ce_mode &&
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!memcmp(a->sha1, b->sha1, 20);
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}
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/*
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* When a CE gets turned into an unmerged entry, we
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* want it to be up-to-date
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*/
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static void verify_uptodate(struct cache_entry *ce)
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{
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struct stat st;
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if (index_only)
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return;
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if (!lstat(ce->name, &st)) {
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unsigned changed = ce_match_stat(ce, &st);
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if (!changed)
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return;
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errno = 0;
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}
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if (errno == ENOENT)
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return;
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die("Entry '%s' not uptodate. Cannot merge.", ce->name);
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}
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static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
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{
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merge->ce_flags |= htons(CE_UPDATE);
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if (old) {
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/*
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* See if we can re-use the old CE directly?
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* That way we get the uptodate stat info.
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*
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* This also removes the UPDATE flag on
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* a match.
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*/
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if (same(old, merge)) {
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*merge = *old;
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} else {
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verify_uptodate(old);
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}
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}
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merge->ce_flags &= ~htons(CE_STAGEMASK);
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add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
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return 1;
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}
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static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
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{
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if (old)
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verify_uptodate(old);
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ce->ce_mode = 0;
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add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
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return 1;
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}
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static int keep_entry(struct cache_entry *ce)
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{
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add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
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return 1;
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}
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#if DBRT_DEBUG
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static void show_stage_entry(FILE *o,
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const char *label, const struct cache_entry *ce)
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{
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if (!ce)
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fprintf(o, "%s (missing)\n", label);
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else
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fprintf(o, "%s%06o %s %d\t%s\n",
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label,
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ntohl(ce->ce_mode),
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sha1_to_hex(ce->sha1),
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ce_stage(ce),
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ce->name);
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}
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#endif
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static int threeway_merge(struct cache_entry **stages)
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{
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struct cache_entry *index;
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struct cache_entry *head;
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struct cache_entry *remote = stages[head_idx + 1];
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int count;
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int head_match = 0;
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int remote_match = 0;
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int df_conflict_head = 0;
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int df_conflict_remote = 0;
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int any_anc_missing = 0;
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int i;
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for (i = 1; i < head_idx; i++) {
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if (!stages[i])
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any_anc_missing = 1;
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}
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index = stages[0];
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head = stages[head_idx];
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if (head == &df_conflict_entry) {
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df_conflict_head = 1;
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head = NULL;
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}
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if (remote == &df_conflict_entry) {
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df_conflict_remote = 1;
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remote = NULL;
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}
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/* First, if there's a #16 situation, note that to prevent #13
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* and #14.
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*/
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if (!same(remote, head)) {
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for (i = 1; i < head_idx; i++) {
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if (same(stages[i], head)) {
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head_match = i;
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}
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if (same(stages[i], remote)) {
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remote_match = i;
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}
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}
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}
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/* We start with cases where the index is allowed to match
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* something other than the head: #14(ALT) and #2ALT, where it
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* is permitted to match the result instead.
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*/
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/* #14, #14ALT, #2ALT */
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if (remote && !df_conflict_head && head_match && !remote_match) {
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if (index && !same(index, remote) && !same(index, head))
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reject_merge(index);
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return merged_entry(remote, index);
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}
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/*
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* If we have an entry in the index cache, then we want to
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* make sure that it matches head.
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*/
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if (index && !same(index, head)) {
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reject_merge(index);
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}
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if (head) {
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/* #5ALT, #15 */
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if (same(head, remote))
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return merged_entry(head, index);
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/* #13, #3ALT */
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if (!df_conflict_remote && remote_match && !head_match)
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return merged_entry(head, index);
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}
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/* #1 */
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if (!head && !remote && any_anc_missing)
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return 0;
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/* Below are "no merge" cases, which require that the index be
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* up-to-date to avoid the files getting overwritten with
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* conflict resolution files.
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*/
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if (index) {
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verify_uptodate(index);
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}
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nontrivial_merge = 1;
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/* #2, #3, #4, #6, #7, #9, #11. */
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count = 0;
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if (!head_match || !remote_match) {
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for (i = 1; i < head_idx; i++) {
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if (stages[i]) {
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keep_entry(stages[i]);
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count++;
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break;
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}
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}
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}
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#if DBRT_DEBUG
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else {
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fprintf(stderr, "read-tree: warning #16 detected\n");
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show_stage_entry(stderr, "head ", stages[head_match]);
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show_stage_entry(stderr, "remote ", stages[remote_match]);
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}
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#endif
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if (head) { count += keep_entry(head); }
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if (remote) { count += keep_entry(remote); }
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return count;
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}
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/*
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* Two-way merge.
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*
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* The rule is to "carry forward" what is in the index without losing
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* information across a "fast forward", favoring a successful merge
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* over a merge failure when it makes sense. For details of the
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* "carry forward" rule, please see <Documentation/git-read-tree.txt>.
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*
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*/
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static int twoway_merge(struct cache_entry **src)
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{
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struct cache_entry *current = src[0];
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struct cache_entry *oldtree = src[1], *newtree = src[2];
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|
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if (merge_size != 2)
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return error("Cannot do a twoway merge of %d trees\n",
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merge_size);
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if (current) {
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if ((!oldtree && !newtree) || /* 4 and 5 */
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(!oldtree && newtree &&
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same(current, newtree)) || /* 6 and 7 */
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(oldtree && newtree &&
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same(oldtree, newtree)) || /* 14 and 15 */
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(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);
|
|
}
|
|
else if (oldtree && newtree &&
|
|
same(current, oldtree) && !same(current, newtree)) {
|
|
/* 20 or 21 */
|
|
return merged_entry(newtree, current);
|
|
}
|
|
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);
|
|
else
|
|
return deleted_entry(oldtree, current);
|
|
}
|
|
|
|
/*
|
|
* 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 *old = src[0];
|
|
struct cache_entry *a = src[1];
|
|
|
|
if (merge_size != 1)
|
|
return error("Cannot do a oneway merge of %d trees\n",
|
|
merge_size);
|
|
|
|
if (!a)
|
|
return 0;
|
|
if (old && same(old, a)) {
|
|
return keep_entry(old);
|
|
}
|
|
return merged_entry(a, NULL);
|
|
}
|
|
|
|
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 | -i] <sha1> [<sha2> [<sha3>]])";
|
|
|
|
static struct cache_file cache_file;
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int i, newfd, reset, stage = 0;
|
|
unsigned char sha1[20];
|
|
merge_fn_t fn = NULL;
|
|
|
|
setup_git_directory();
|
|
|
|
newfd = hold_index_file_for_update(&cache_file, get_index_file());
|
|
if (newfd < 0)
|
|
die("unable to create new cachefile");
|
|
|
|
git_config(git_default_config);
|
|
|
|
merge = 0;
|
|
reset = 0;
|
|
for (i = 1; i < argc; i++) {
|
|
const char *arg = argv[i];
|
|
|
|
/* "-u" means "update", meaning that a merge will update
|
|
* the working tree.
|
|
*/
|
|
if (!strcmp(arg, "-u")) {
|
|
update = 1;
|
|
continue;
|
|
}
|
|
|
|
/* "-i" means "index only", meaning that a merge will
|
|
* not even look at the working tree.
|
|
*/
|
|
if (!strcmp(arg, "-i")) {
|
|
index_only = 1;
|
|
continue;
|
|
}
|
|
|
|
/* This differs from "-m" in that we'll silently ignore unmerged entries */
|
|
if (!strcmp(arg, "--reset")) {
|
|
if (stage || merge)
|
|
usage(read_tree_usage);
|
|
reset = 1;
|
|
merge = 1;
|
|
stage = 1;
|
|
read_cache_unmerged();
|
|
continue;
|
|
}
|
|
|
|
if (!strcmp(arg, "--trivial")) {
|
|
trivial_merges_only = 1;
|
|
continue;
|
|
}
|
|
|
|
/* "-m" stands for "merge", meaning we start in stage 1 */
|
|
if (!strcmp(arg, "-m")) {
|
|
if (stage || merge)
|
|
usage(read_tree_usage);
|
|
if (read_cache_unmerged())
|
|
die("you need to resolve your current index first");
|
|
stage = 1;
|
|
merge = 1;
|
|
continue;
|
|
}
|
|
|
|
/* using -u and -i at the same time makes no sense */
|
|
if (1 < index_only + update)
|
|
usage(read_tree_usage);
|
|
|
|
if (get_sha1(arg, sha1) < 0)
|
|
usage(read_tree_usage);
|
|
if (list_tree(sha1) < 0)
|
|
die("failed to unpack tree object %s", arg);
|
|
stage++;
|
|
}
|
|
if ((update||index_only) && !merge)
|
|
usage(read_tree_usage);
|
|
|
|
if (merge) {
|
|
if (stage < 2)
|
|
die("just how do you expect me to merge %d trees?", stage-1);
|
|
switch (stage - 1) {
|
|
case 1:
|
|
fn = oneway_merge;
|
|
break;
|
|
case 2:
|
|
fn = twoway_merge;
|
|
break;
|
|
case 3:
|
|
fn = threeway_merge;
|
|
break;
|
|
default:
|
|
fn = threeway_merge;
|
|
break;
|
|
}
|
|
|
|
if (stage - 1 >= 3)
|
|
head_idx = stage - 2;
|
|
else
|
|
head_idx = 1;
|
|
}
|
|
|
|
unpack_trees(fn);
|
|
if (write_cache(newfd, active_cache, active_nr) ||
|
|
commit_index_file(&cache_file))
|
|
die("unable to write new index file");
|
|
return 0;
|
|
}
|