Improve config handling for diff,submodules,attrs

This adds support for a bunch of core.* settings that affect
diff and status, plus fixes up some incorrect implementations
of those settings from before.  Also, this cleans up the
handling of config settings in the new submodules code and
in the old attrs/ignore code.

1 files changed, 80 insertions, 21 deletions

diff --git a/src/diff.c b/src/diff.c
index e1016db05..54e8dd166 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -8,6 +8,7 @@
 #include "git2/diff.h"
 #include "diff.h"
 #include "fileops.h"
+#include "config.h"
 
 static void diff_delta__free(git_diff_delta *delta)
 {
@@ -233,15 +234,38 @@ static int diff_delta__cmp(const void *a, const void *b)
 	return val ? val : ((int)da->status - (int)db->status);
 }
 
+static int config_bool(git_config *cfg, const char *name, int defvalue)
+{
+	int val = defvalue;
+	if (git_config_get_bool(cfg, name, &val) < 0)
+		giterr_clear();
+	return val;
+}
+
 static git_diff_list *git_diff_list_alloc(
 	git_repository *repo, const git_diff_options *opts)
 {
+	git_config *cfg;
 	git_diff_list *diff = git__calloc(1, sizeof(git_diff_list));
 	if (diff == NULL)
 		return NULL;
 
 	diff->repo = repo;
 
+	/* load config values that affect diff behavior */
+	if (git_repository_config(&cfg, repo) < 0)
+		goto fail;
+	if (config_bool(cfg, "core.symlinks", 1))
+		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_HAS_SYMLINKS;
+	if (config_bool(cfg, "core.ignorestat", 0))
+		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_ASSUME_UNCHANGED;
+	if (config_bool(cfg, "core.filemode", 1))
+		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_EXEC_BIT;
+	if (config_bool(cfg, "core.trustctime", 1))
+		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_CTIME;
+	/* Don't set GIT_DIFFCAPS_USE_DEV - compile time option in core git */
+	git_config_free(cfg);
+
 	if (opts == NULL)
 		return diff;
 
@@ -252,10 +276,8 @@ static git_diff_list *git_diff_list_alloc(
 	diff->opts.dst_prefix = diff_strdup_prefix(
 		opts->dst_prefix ? opts->dst_prefix : DIFF_DST_PREFIX_DEFAULT);
 
-	if (!diff->opts.src_prefix || !diff->opts.dst_prefix) {
-		git__free(diff);
-		return NULL;
-	}
+	if (!diff->opts.src_prefix || !diff->opts.dst_prefix)
+		goto fail;
 
 	if (diff->opts.flags & GIT_DIFF_REVERSE) {
 		char *swap = diff->opts.src_prefix;
@@ -263,16 +285,19 @@ static git_diff_list *git_diff_list_alloc(
 		diff->opts.dst_prefix = swap;
 	}
 
-	if (git_vector_init(&diff->deltas, 0, diff_delta__cmp) < 0) {
-		git__free(diff->opts.src_prefix);
-		git__free(diff->opts.dst_prefix);
-		git__free(diff);
-		return NULL;
-	}
+	if (git_vector_init(&diff->deltas, 0, diff_delta__cmp) < 0)
+		goto fail;
 
 	/* TODO: do something safe with the pathspec strarray */
 
 	return diff;
+
+fail:
+	git_vector_free(&diff->deltas);
+	git__free(diff->opts.src_prefix);
+	git__free(diff->opts.dst_prefix);
+	git__free(diff);
+	return NULL;
 }
 
 void git_diff_list_free(git_diff_list *diff)
@@ -326,6 +351,8 @@ static int oid_for_workdir_item(
 	return result;
 }
 
+#define EXEC_BIT_MASK 0000111
+
 static int maybe_modified(
 	git_iterator *old,
 	const git_index_entry *oitem,
@@ -335,16 +362,33 @@ static int maybe_modified(
 {
 	git_oid noid, *use_noid = NULL;
 	git_delta_t status = GIT_DELTA_MODIFIED;
+	unsigned int omode = oitem->mode;
+	unsigned int nmode = nitem->mode;
 
 	GIT_UNUSED(old);
 
-	/* support "assume unchanged" & "skip worktree" bits */
-	if ((oitem->flags_extended & GIT_IDXENTRY_INTENT_TO_ADD) != 0 ||
-		(oitem->flags_extended & GIT_IDXENTRY_SKIP_WORKTREE) != 0)
+	/* on platforms with no symlinks, promote plain files to symlinks */
+	if (S_ISLNK(omode) && S_ISREG(nmode) &&
+		!(diff->diffcaps & GIT_DIFFCAPS_HAS_SYMLINKS))
+		nmode = GIT_MODE_TYPE(omode) | (nmode & GIT_MODE_PERMS_MASK);
+
+	/* on platforms with no execmode, clear exec bit from comparisons */
+	if (!(diff->diffcaps & GIT_DIFFCAPS_TRUST_EXEC_BIT)) {
+		omode = omode & ~EXEC_BIT_MASK;
+		nmode = nmode & ~EXEC_BIT_MASK;
+	}
+
+	/* support "assume unchanged" (badly, b/c we still stat everything) */
+	if ((diff->diffcaps & GIT_DIFFCAPS_ASSUME_UNCHANGED) != 0)
+		status = (oitem->flags_extended & GIT_IDXENTRY_INTENT_TO_ADD) ?
+			GIT_DELTA_MODIFIED : GIT_DELTA_UNMODIFIED;
+
+	/* support "skip worktree" index bit */
+	else if ((oitem->flags_extended & GIT_IDXENTRY_SKIP_WORKTREE) != 0)
 		status = GIT_DELTA_UNMODIFIED;
 
 	/* if basic type of file changed, then split into delete and add */
-	else if (GIT_MODE_TYPE(oitem->mode) != GIT_MODE_TYPE(nitem->mode)) {
+	else if (GIT_MODE_TYPE(omode) != GIT_MODE_TYPE(nmode)) {
 		if (diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem) < 0 ||
 			diff_delta__from_one(diff, GIT_DELTA_ADDED, nitem) < 0)
 			return -1;
@@ -353,24 +397,39 @@ static int maybe_modified(
 
 	/* if oids and modes match, then file is unmodified */
 	else if (git_oid_cmp(&oitem->oid, &nitem->oid) == 0 &&
-			oitem->mode == nitem->mode)
+			 omode == nmode)
 		status = GIT_DELTA_UNMODIFIED;
 
 	/* if we have a workdir item with an unknown oid, check deeper */
 	else if (git_oid_iszero(&nitem->oid) && new->type == GIT_ITERATOR_WORKDIR) {
+		/* TODO: add check against index file st_mtime to avoid racy-git */
+
 		/* if they files look exactly alike, then we'll assume the same */
 		if (oitem->file_size == nitem->file_size &&
-			oitem->ctime.seconds == nitem->ctime.seconds &&
+			(!(diff->diffcaps & GIT_DIFFCAPS_TRUST_CTIME) ||
+			 (oitem->ctime.seconds == nitem->ctime.seconds)) &&
 			oitem->mtime.seconds == nitem->mtime.seconds &&
-			oitem->dev == nitem->dev &&
+			(!(diff->diffcaps & GIT_DIFFCAPS_USE_DEV) ||
+			 (oitem->dev == nitem->dev)) &&
 			oitem->ino == nitem->ino &&
 			oitem->uid == nitem->uid &&
 			oitem->gid == nitem->gid)
 			status = GIT_DELTA_UNMODIFIED;
 
-		/* TODO? should we do anything special with submodules? */
-		else if (S_ISGITLINK(nitem->mode))
-			status = GIT_DELTA_UNMODIFIED;
+		else if (S_ISGITLINK(nmode)) {
+			git_submodule *sub;
+
+			if ((diff->opts.flags & GIT_DIFF_IGNORE_SUBMODULES) != 0)
+				status = GIT_DELTA_UNMODIFIED;
+			else if (git_submodule_lookup(&sub, diff->repo, nitem->path) < 0)
+				return -1;
+			else if (sub->ignore == GIT_SUBMODULE_IGNORE_ALL)
+				status = GIT_DELTA_UNMODIFIED;
+			else {
+				/* TODO: support other GIT_SUBMODULE_IGNORE values */
+				status = GIT_DELTA_UNMODIFIED;
+			}
+		}
 
 		/* TODO: check git attributes so we will not have to read the file
 		 * in if it is marked binary.
@@ -380,7 +439,7 @@ static int maybe_modified(
 			return -1;
 
 		else if (git_oid_cmp(&oitem->oid, &noid) == 0 &&
-			oitem->mode == nitem->mode)
+				 omode == nmode)
 			status = GIT_DELTA_UNMODIFIED;
 
 		/* store calculated oid so we don't have to recalc later */