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[PATCHv6 19/31] merge-recursive: add get_directory_renames()

From
Elijah Newren <newren@gmail.com>
Date
Jan 5, 2018, 20:26 UTC
Message-ID
<20180105202711.24311-20-newren@gmail.com>
In-Reply-To
<20180105202711.24311-1-newren@gmail.com>

This populates a list of directory renames for us. The list of directory renames is not yet used, but will be in subsequent commits.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 152 insertions(+), 3 deletions(-)
diff --git a/merge-recursive.c b/merge-recursive.c
index c5932d5c5..6aef357e7 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1384,6 +1384,138 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 	return ret;
 }
 
+static void get_renamed_dir_portion(const char *old_path, const char *new_path,
+				    char **old_dir, char **new_dir)
+{
+	char *end_of_old, *end_of_new;
+	int old_len, new_len;
+
+	*old_dir = NULL;
+	*new_dir = NULL;
+
+	/* For
+	 *    "a/b/c/d/foo.c" -> "a/b/something-else/d/foo.c"
+	 * the "d/foo.c" part is the same, we just want to know that
+	 *    "a/b/c" was renamed to "a/b/something-else"
+	 * so, for this example, this function returns "a/b/c" in
+	 * *old_dir and "a/b/something-else" in *new_dir.
+	 *
+	 * Also, if the basename of the file changed, we don't care.  We
+	 * want to know which portion of the directory, if any, changed.
+	 */
+	end_of_old = strrchr(old_path, '/');
+	end_of_new = strrchr(new_path, '/');
+
+	if (end_of_old == NULL || end_of_new == NULL)
+		return;
+	while (*--end_of_new == *--end_of_old &&
+	       end_of_old != old_path &&
+	       end_of_new != new_path)
+		; /* Do nothing; all in the while loop */
+	/*
+	 * We've found the first non-matching character in the directory
+	 * paths.  That means the current directory we were comparing
+	 * represents the rename.  Move end_of_old and end_of_new back
+	 * to the full directory name.
+	 */
+	if (*end_of_old == '/')
+		end_of_old++;
+	if (*end_of_old != '/')
+		end_of_new++;
+	end_of_old = strchr(end_of_old, '/');
+	end_of_new = strchr(end_of_new, '/');
+
+	/*
+	 * It may have been the case that old_path and new_path were the same
+	 * directory all along.  Don't claim a rename if they're the same.
+	 */
+	old_len = end_of_old - old_path;
+	new_len = end_of_new - new_path;
+
+	if (old_len != new_len || strncmp(old_path, new_path, old_len)) {
+		*old_dir = xstrndup(old_path, old_len);
+		*new_dir = xstrndup(new_path, new_len);
+	}
+}
+
+static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
+					     struct tree *tree)
+{
+	struct hashmap *dir_renames;
+	struct hashmap_iter iter;
+	struct dir_rename_entry *entry;
+	int i;
+
+	dir_renames = malloc(sizeof(struct hashmap));
+	dir_rename_init(dir_renames);
+	for (i = 0; i < pairs->nr; ++i) {
+		struct string_list_item *item;
+		int *count;
+		struct diff_filepair *pair = pairs->queue[i];
+		char *old_dir, *new_dir;
+
+		/* File not part of directory rename if it wasn't renamed */
+		if (pair->status != 'R')
+			continue;
+
+		get_renamed_dir_portion(pair->one->path, pair->two->path,
+					&old_dir,        &new_dir);
+		if (!old_dir)
+			/* Directory didn't change at all; ignore this one. */
+			continue;
+
+		entry = dir_rename_find_entry(dir_renames, old_dir);
+		if (!entry) {
+			entry = xmalloc(sizeof(struct dir_rename_entry));
+			dir_rename_entry_init(entry, old_dir);
+			hashmap_put(dir_renames, entry);
+		} else {
+			free(old_dir);
+		}
+		item = string_list_lookup(&entry->possible_new_dirs, new_dir);
+		if (!item) {
+			item = string_list_insert(&entry->possible_new_dirs,
+						  new_dir);
+			item->util = xcalloc(1, sizeof(int));
+		} else {
+			free(new_dir);
+		}
+		count = item->util;
+		*count += 1;
+	}
+
+	hashmap_iter_init(dir_renames, &iter);
+	while ((entry = hashmap_iter_next(&iter))) {
+		int max = 0;
+		int bad_max = 0;
+		char *best = NULL;
+
+		for (i = 0; i < entry->possible_new_dirs.nr; i++) {
+			int *count = entry->possible_new_dirs.items[i].util;
+
+			if (*count == max)
+				bad_max = max;
+			else if (*count > max) {
+				max = *count;
+				best = entry->possible_new_dirs.items[i].string;
+			}
+		}
+		if (bad_max == max)
+			entry->non_unique_new_dir = 1;
+		else {
+			assert(entry->new_dir.len == 0);
+			strbuf_addstr(&entry->new_dir, best);
+		}
+		/* Strings were xstrndup'ed before inserting into string-list,
+		 * so ask string_list to remove the entries for us.
+		 */
+		entry->possible_new_dirs.strdup_strings = 1;
+		string_list_clear(&entry->possible_new_dirs, 1);
+	}
+
+	return dir_renames;
+}
+
 /*
  * Get information of all renames which occurred in 'pairs', making use of
  * any implicit directory renames inferred from the other side of history.
@@ -1695,8 +1827,21 @@ struct rename_info {
 	struct string_list *merge_renames;
 };
 
-static void initial_cleanup_rename(struct diff_queue_struct *pairs)
+static void initial_cleanup_rename(struct diff_queue_struct *pairs,
+				   struct hashmap *dir_renames)
 {
+	struct hashmap_iter iter;
+	struct dir_rename_entry *e;
+
+	hashmap_iter_init(dir_renames, &iter);
+	while ((e = hashmap_iter_next(&iter))) {
+		free(e->dir);
+		strbuf_release(&e->new_dir);
+		/* possible_new_dirs already cleared in get_directory_renames */
+	}
+	hashmap_free(dir_renames, 1);
+	free(dir_renames);
+
 	free(pairs->queue);
 	free(pairs);
 }
@@ -1709,6 +1854,7 @@ static int handle_renames(struct merge_options *o,
 			  struct rename_info *ri)
 {
 	struct diff_queue_struct *head_pairs, *merge_pairs;
+	struct hashmap *dir_re_head, *dir_re_merge;
 	int clean;
 
 	ri->head_renames = NULL;
@@ -1720,6 +1866,9 @@ static int handle_renames(struct merge_options *o,
 	head_pairs = get_diffpairs(o, common, head);
 	merge_pairs = get_diffpairs(o, common, merge);
 
+	dir_re_head = get_directory_renames(head_pairs, head);
+	dir_re_merge = get_directory_renames(merge_pairs, merge);
+
 	ri->head_renames  = get_renames(o, head_pairs, head,
 					 common, head, merge, entries);
 	ri->merge_renames = get_renames(o, merge_pairs, merge,
@@ -1731,8 +1880,8 @@ static int handle_renames(struct merge_options *o,
 	 * data structures are still needed and referenced in
 	 * process_entry().  But there are a few things we can free now.
 	 */
-	initial_cleanup_rename(head_pairs);
-	initial_cleanup_rename(merge_pairs);
+	initial_cleanup_rename(head_pairs, dir_re_head);
+	initial_cleanup_rename(merge_pairs, dir_re_merge);
 
 	return clean;
 }

-- 
2.14.2
Previous: Elijah NewrenNext: Elijah Newren
Message 8 of 34 in “[PATCHv6 00/31] Add directory rename detection to git”
  1. Elijah NewrenJan 5, 2018
  2. 01/31 directory rename detection: basic testcasesElijah Newren, Jan 5, 2018
  3. 07/31 directory rename detection: more involved edge/corner testcasesElijah Newren, Jan 5, 2018
  4. 08/31 directory rename detection: testcases exploring possibly suboptimal mergesElijah Newren, Jan 5, 2018
  5. 05/31 directory rename detection: files/directories in the way of some renamesElijah Newren, Jan 5, 2018
  6. 15/31 merge-recursive: make !o->detect_rename codepath more obviousElijah Newren, Jan 5, 2018
  7. 17/31 merge-recursive: add a new hashmap for storing directory renamesElijah Newren, Jan 5, 2018
  8. 19/31 merge-recursive: add get_directory_renames()Elijah Newren, Jan 5, 2018
  9. 18/31 merge-recursive: make a helper function for cleanup for handle_renamesElijah Newren, Jan 5, 2018
  10. 23/31 merge-recursive: check for file level conflicts then get new nameElijah Newren, Jan 5, 2018
  11. 25/31 merge-recursive: apply necessary modifications for directory renamesElijah Newren, Jan 5, 2018
  12. 28/31 merge-recursive: fix remaining directory rename + dirty overwrite casesElijah Newren, Jan 5, 2018
  13. 30/31 merge-recursive: avoid spurious rename/rename conflict from dir renamesElijah Newren, Jan 5, 2018
  14. 29/31 directory rename detection: new testcases showcasing a pair of bugsElijah Newren, Jan 5, 2018
  15. 31/31 merge-recursive: ensure we write updates for directory-renamed fileElijah Newren, Jan 5, 2018
  16. 26/31 merge-recursive: avoid clobbering untracked files with directory renamesElijah Newren, Jan 5, 2018
  17. 27/31 merge-recursive: fix overwriting dirty files involved in renamesElijah Newren, Jan 5, 2018
  18. 24/31 merge-recursive: when comparing files, don't include treesElijah Newren, Jan 5, 2018
  19. 22/31 merge-recursive: add computation of collisions due to dir rename & mergingElijah Newren, Jan 5, 2018
  20. 20/31 merge-recursive: check for directory level conflictsElijah Newren, Jan 5, 2018
  21. 21/31 merge-recursive: add a new hashmap for storing file collisionsElijah Newren, Jan 5, 2018
  22. 10/31 directory rename detection: tests for handling overwriting untracked filesElijah Newren, Jan 5, 2018
  23. 16/31 merge-recursive: split out code for determining diff_filepairsElijah Newren, Jan 5, 2018
  24. 06/31 directory rename detection: testcases checking which side did the renameElijah Newren, Jan 5, 2018
  25. 14/31 merge-recursive: fix leaks of allocated renames and diff_filepairsElijah Newren, Jan 5, 2018
  26. 09/31 directory rename detection: miscellaneous testcases to complete coverageElijah Newren, Jan 5, 2018
  27. 13/31 merge-recursive: introduce new functions to handle rename logicElijah Newren, Jan 5, 2018
  28. 02/31 directory rename detection: directory splitting testcasesElijah Newren, Jan 5, 2018
  29. 11/31 directory rename detection: tests for handling overwriting dirty filesElijah Newren, Jan 5, 2018
  30. 12/31 merge-recursive: move the get_renames() functionElijah Newren, Jan 5, 2018
  31. 04/31 directory rename detection: partially renamed directory testcase/discussionElijah Newren, Jan 5, 2018
  32. 03/31 directory rename detection: testcases to avoid taking detection too farElijah Newren, Jan 5, 2018
  33. SZEDER GáborJan 26, 2018
  34. Elijah NewrenJan 26, 2018

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