#include "cache.h"
static int stage = 0;
+static int update = 0;
static int unpack_tree(unsigned char *sha1)
{
unsigned long size;
int ret;
- buffer = read_object_with_reference(sha1, "tree", &size, 0);
+ buffer = read_object_with_reference(sha1, "tree", &size, NULL);
if (!buffer)
return -1;
ret = read_tree(buffer, size, stage);
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);
+}
+
+#define CHECK_OLD(ce) if (old && same(old, ce)) { verify_uptodate(old); old = NULL; }
+
static void trivially_merge_cache(struct cache_entry **src, int nr)
{
- static struct cache_entry null_entry;
struct cache_entry **dst = src;
- struct cache_entry *old = &null_entry;
+ 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 (nr > 2 && (result = merge_entries(ce, src[1], src[2])) != NULL) {
+ if (old && !path_matches(old, ce))
+ reject_merge(old);
+ if (nr > 1 && (result = merge_entries(ce, src[0], src[1])) != 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 (path_matches(result, old) && same(result, old))
+ if (old && same(old, result)) {
*result = *old;
+ old = NULL;
+ }
+ CHECK_OLD(ce);
+ CHECK_OLD(src[0]);
+ CHECK_OLD(src[1]);
ce = result;
ce->ce_flags &= ~htons(CE_STAGEMASK);
src += 2;
nr -= 2;
active_nr -= 2;
}
+
+ /*
+ * If we had an old entry that we now effectively
+ * overwrite, make sure it wasn't dirty.
+ */
+ CHECK_OLD(ce);
*dst++ = ce;
- src++;
- nr--;
+ }
+ if (old)
+ reject_merge(old);
+}
+
+/*
+ * When we find a "stage2" entry in the two-way merge, that's
+ * the one that will remain. If we have an exact old match,
+ * we don't care whether the file is up-to-date or not, we just
+ * re-use the thing directly.
+ *
+ * If we didn't have an exact match, then we want to make sure
+ * that we've seen a stage1 that matched the old, and that the
+ * old file was up-to-date. Because it will be gone after this
+ * merge..
+ */
+static void twoway_check(struct cache_entry *old, int seen_stage1, struct cache_entry *ce)
+{
+ if (path_matches(old, ce)) {
+ /*
+ * This also removes the UPDATE flag on
+ * a match
+ */
+ if (same(old, ce)) {
+ *ce = *old;
+ return;
+ }
+ if (!seen_stage1)
+ reject_merge(old);
+ }
+ verify_uptodate(old);
+}
+
+/*
+ * 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)
+{
+ int seen_stage1 = 0;
+ struct cache_entry *old = NULL;
+ struct cache_entry **dst = src;
+
+ while (nr--) {
+ struct cache_entry *ce = *src++;
+ int stage = ce_stage(ce);
+
+ switch (stage) {
+ case 0:
+ if (old)
+ reject_merge(old);
+ old = ce;
+ seen_stage1 = 0;
+ active_nr--;
+ continue;
+
+ case 1:
+ active_nr--;
+ if (!old)
+ continue;
+ if (!path_matches(old, ce) || !same(old, ce))
+ reject_merge(old);
+ seen_stage1 = 1;
+ continue;
+
+ case 2:
+ ce->ce_flags |= htons(CE_UPDATE);
+ if (old) {
+ twoway_check(old, seen_stage1, ce);
+ old = NULL;
+ }
+ ce->ce_flags &= ~htons(CE_STAGEMASK);
+ *dst++ = ce;
+ continue;
+ }
+ die("impossible two-way stage");
+ }
+
+ /*
+ * Unmatched with a new entry? Make sure it was
+ * at least uptodate in the working directory _and_
+ * the original tree..
+ */
+ if (old) {
+ if (!seen_stage1)
+ reject_merge(old);
+ verify_uptodate(old);
}
}
{
static struct cache_entry null_entry;
struct cache_entry **dst = src;
- struct cache_entry *old = &null_entry;
-
- while (nr) {
- struct cache_entry *ce;
+ 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 (<sha> | -m <sha1> [<sha2> <sha3>])";
+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 (<sha> | -m <sha1> [<sha2> [<sha3>]])";
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;
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);
projects / git.git / blobdiff