Add -vcs_ignore flag via libgit2

Author: losnappas

build/pkgconf.sh

@@ -80,6 +80,9 @@ for LIB; do
         oniguruma)
             LDLIB=-lonig
             ;;
+        libgit2)
+            LDLIB=-lgit2
+            ;;
         *)
             printf 'error: Unknown package %s\n' "$LIB" >&2
             exit 1

build/prelude.mk

@@ -67,4 +67,5 @@ ALL_PKGS := \
     libcap \
     libselinux \
     liburing \
-    oniguruma
+    oniguruma \
+    libgit2

build/with/libgit2.c

@@ -0,0 +1,6 @@
+#include <git2.h>
+
+int main(void) {
+	git_libgit2_init();
+	return 0;
+}

configure

@@ -53,6 +53,7 @@ External dependencies are auto-detected by default, but you can build --with or
   --with-libselinux  --without-libselinux
   --with-liburing    --without-liburing
   --with-oniguruma   --without-oniguruma
+  --with-libgit2     --without-libgit2
 
 Packaging:
 
@@ -146,7 +147,7 @@ for arg; do
     case "$arg" in
         --enable-*|--disable-*)
             case "$name" in
-                libacl|libcap|libselinux|liburing|oniguruma)
+                libacl|libcap|libselinux|liburing|oniguruma|libgit2)
                     old="$arg"
                     case "$arg" in
                         --enable-*) arg="--with-${arg#--*-}" ;;
@@ -177,7 +178,7 @@ for arg; do
 
         --with-*|--without-*)
             case "$name" in
-                libacl|libcap|libselinux|liburing|oniguruma)
+                libacl|libcap|libselinux|liburing|oniguruma|libgit2)
                     set -- "$@" "WITH_$NAME=$yn"
                     ;;
                 *)

src/ctx.c

@@ -24,6 +24,10 @@
 #include <time.h>
 #include <unistd.h>
 
+#ifdef BFS_WITH_LIBGIT2
+#include <git2.h>
+#endif
+
 struct bfs_ctx *bfs_ctx_new(void) {
 	struct bfs_ctx *ctx = ZALLOC(struct bfs_ctx);
 	if (!ctx) {
@@ -69,6 +73,10 @@ struct bfs_ctx *bfs_ctx_new(void) {
 		goto fail;
 	}
 
+#ifdef BFS_WITH_LIBGIT2
+	git_libgit2_init();
+#endif
+
 	return ctx;
 
 fail:
@@ -288,8 +296,67 @@ int bfs_ctx_free(struct bfs_ctx *ctx) {
 
 		free(ctx->kinds);
 		free(ctx->argv);
+
+#ifdef BFS_WITH_LIBGIT2
+		if (ctx->git_repo) {
+			git_repository_free(ctx->git_repo);
+		}
+		git_libgit2_shutdown();
+#endif
+
 		free(ctx);
 	}
 
 	return ret;
 }
+
+#ifdef BFS_WITH_LIBGIT2
+/** Find the git repository for a given path. */
+static struct git_repository *bfs_git_repository_open(const struct bfs_ctx *ctx, const char *path) {
+	bfs_debug(ctx, DEBUG_SEARCH, "Opening git repository for '%s'\n", path);
+	struct git_repository *repo = NULL;
+	int error = git_repository_open_ext(&repo, path,
+			GIT_REPOSITORY_OPEN_FROM_ENV,
+			NULL);
+	if (error != 0) {
+		if (error != GIT_ENOTFOUND) {
+			bfs_warning(ctx, "git_repository_open_ext('%s'): %s.\n",
+					path, git_error_last()->message);
+		}
+		bfs_debug(ctx, DEBUG_SEARCH, "Failed to open git repository for '%s': %s\n", path, git_error_last()->message);
+		return NULL;
+	}
+	bfs_debug(ctx, DEBUG_SEARCH, "Successfully opened git repository for '%s'\n", path);
+	return repo;
+}
+
+/** Check if a path is ignored by git. */
+bool bfs_git_ignored(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf) {
+	struct bfs_ctx *mut = (struct bfs_ctx *)ctx;
+	if (strcmp(ftwbuf->path, ".") == 0) {
+		return false;
+	}
+
+	if (!mut->git_repo) {
+		mut->git_repo = bfs_git_repository_open(ctx, ftwbuf->root);
+		if (!mut->git_repo) {
+			return false;
+		}
+	}
+
+	int ignored = 0;
+	const char *git_path = ftwbuf->path;
+	if (git_path[0] == '.' && git_path[1] == '/') {
+	    git_path += 2; // Slice off "./"
+	}
+	int error = git_ignore_path_is_ignored(&ignored, mut->git_repo, git_path);
+	if (error != 0) {
+		bfs_warning(ctx, "%pP: git_ignore_check_path(): %s.\n",
+				ftwbuf, git_error_last()->message);
+		return false;
+	}
+
+	bfs_debug(ctx, DEBUG_SEARCH, "%pP: Ignored by git: %s\n", ftwbuf, ignored ? "true" : "false");
+	return ignored;
+}
+#endif // BFS_WITH_LIBGIT2

src/ctx.h

@@ -20,6 +20,7 @@
 #include <time.h>
 
 struct CFILE;
+struct git_repository;
 
 /**
  * The execution context for bfs.
@@ -62,6 +63,8 @@ struct bfs_ctx {
 	int optlevel;
 	/** Debugging flags (-D). */
 	enum debug_flags debug;
+	/** Whether to ignore files ignored by VCS (e.g. git). */
+	bool ignore_vcs;
 	/** Whether to ignore deletions that race with bfs (-ignore_readdir_race). */
 	bool ignore_races;
 	/** Whether to follow POSIXisms more closely ($POSIXLY_CORRECT). */
@@ -120,6 +123,11 @@ struct bfs_ctx {
 
 	/** The current time. */
 	struct timespec now;
+
+#ifdef BFS_WITH_LIBGIT2
+	/** The git repository for the current root. */
+	struct git_repository *git_repo;
+#endif
 };
 
 /**
@@ -181,4 +189,7 @@ void bfs_ctx_dump(const struct bfs_ctx *ctx, enum debug_flags flag);
  */
 int bfs_ctx_free(struct bfs_ctx *ctx);
 
+#ifdef BFS_WITH_LIBGIT2
+bool bfs_git_ignored(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf);
+#endif // BFS_WITH_LIBGIT2
 #endif // BFS_CTX_H

src/eval.c

@@ -49,6 +49,10 @@
 #include <unistd.h>
 #include <wchar.h>
 
+#ifdef BFS_WITH_LIBGIT2
+#include <git2.h>
+#endif
+
 struct bfs_eval {
 	/** Data about the current file. */
 	const struct BFTW *ftwbuf;
@@ -1505,6 +1509,13 @@ static enum bftw_action eval_callback(const struct BFTW *ftwbuf, void *ptr) {
 		}
 	}
 
+#ifdef BFS_WITH_LIBGIT2
+	if (ctx->ignore_vcs && bfs_git_ignored(ctx, ftwbuf)) {
+		state.action = BFTW_PRUNE;
+		goto done;
+	}
+#endif
+
 	if (eval_expr(ctx->exclude, &state)) {
 		state.action = BFTW_PRUNE;
 		goto done;

src/parse.c

@@ -1584,6 +1584,14 @@ static struct bfs_expr *parse_hidden(struct bfs_parser *parser, int arg1, int ar
 	return parse_nullary_test(parser, eval_hidden);
 }
 
+/**
+ * Parse -ignore-vcs.
+ */
+static struct bfs_expr *parse_ignore_vcs(struct bfs_parser *parser, int arg1, int arg2) {
+	parser->ctx->ignore_vcs = true;
+	return parse_nullary_option(parser);
+}
+
 /**
  * Parse -(no)?ignore_readdir_race.
  */
@@ -2774,6 +2782,8 @@ static struct bfs_expr *parse_help(struct bfs_parser *parser, int arg1, int arg2
 	cfprintf(cout, "      Search the NUL ('\\0')-separated paths from ${bld}FILE${rs} (${bld}-${rs} for standard input).\n");
 	cfprintf(cout, "  ${blu}-follow${rs}\n");
 	cfprintf(cout, "      Follow all symbolic links (same as ${cyn}-L${rs})\n");
+	cfprintf(cout, "  ${blu}-ignore_vcs${rs}\n");
+	cfprintf(cout, "      Ignore files and directories ignored by version control systems (e.g. git)\n");
 	cfprintf(cout, "  ${blu}-ignore_readdir_race${rs}\n");
 	cfprintf(cout, "  ${blu}-noignore_readdir_race${rs}\n");
 	cfprintf(cout, "      Whether to report an error if ${ex}%s${rs} detects that the file tree is modified\n",
@@ -3088,6 +3098,7 @@ static const struct table_entry parse_table[] = {
 	{"-group", BFS_TEST, parse_group},
 	{"-help", BFS_ACTION, parse_help},
 	{"-hidden", BFS_TEST, parse_hidden},
+	{"-ignore_vcs", BFS_OPTION, parse_ignore_vcs},
 	{"-ignore_readdir_race", BFS_OPTION, parse_ignore_races, true},
 	{"-ilname", BFS_TEST, parse_lname, true},
 	{"-iname", BFS_TEST, parse_name, true},
@@ -3807,6 +3818,10 @@ void bfs_ctx_dump(const struct bfs_ctx *ctx, enum debug_flags flag) {
 		cfprintf(cerr, " ${blu}-xdev${rs}");
 	}
 
+	if (ctx->ignore_vcs) {
+		cfprintf(cerr, " ${blu}-ignore_vcs${rs}");
+	}
+
 	fputs("\n", stderr);
 
 	bfs_debug(ctx, flag, "(${red}-exclude${rs}\n");
@@ -3838,6 +3853,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 	}
 
 	ctx->argc = argc;
+	ctx->ignore_vcs = false;
 	ctx->argv = xmemdup(argv, sizeof_array(char *, argc + 1));
 	if (!ctx->argv) {
 		perror("xmemdup()");

tests/bfs/vcs-ignore.out

@@ -0,0 +1 @@
+./tracked_file

tests/bfs/vcs-ignore.sh

@@ -0,0 +1,24 @@
+cd "$TEST"
+
+# Require git to set up a repository
+command -v git >/dev/null 2>&1 || skip
+
+# Initialize a repo in the temp test dir
+git init -q || skip
+
+# Ignore names starting with "ignored"
+echo "ignored*" > .gitignore
+
+# Create files: one ignored by git, one not
+"$XTOUCH" ignored_file tracked_file || skip
+
+# Detect whether -ignore_vcs has any effect (i.e., built with libgit2)
+invoke_bfs . -name '*_file' -print >"$OUT.base" || fail
+invoke_bfs . -ignore_vcs -name '*_file' -print >"$OUT.ign" || fail
+if cmp -s "$OUT.base" "$OUT.ign"; then
+    # No change => no libgit2 support (or feature disabled). Skip.
+    skip
+fi
+
+# Now snapshot-test the behavior
+bfs_diff . -ignore_vcs -name '*_file' -print