Initial implementation of gitignore support

Adds support for .gitignore files to git_status_foreach() and
git_status_file().  This includes refactoring the gitattributes
code to share logic where possible.  The GIT_STATUS_IGNORED flag
will now be passed in for files that are ignored (provided they
are not already in the index or the head of repo).

1 files changed, 148 insertions, 0 deletions

diff --git a/src/ignore.c b/src/ignore.c
new file mode 100644
index 000000000..8bf22e34a
--- /dev/null
+++ b/src/ignore.c
@@ -0,0 +1,148 @@
+#include "ignore.h"
+#include "path.h"
+#include "git2/config.h"
+
+#define GIT_IGNORE_INTERNAL		"[internal]exclude"
+#define GIT_IGNORE_FILE_INREPO	"info/exclude"
+#define GIT_IGNORE_FILE			".gitignore"
+#define GIT_IGNORE_CONFIG		"core.excludesfile"
+
+static int load_ignore_file(
+	git_repository *GIT_UNUSED(repo), const char *path, git_attr_file **out)
+{
+	int error = GIT_SUCCESS;
+	git_fbuffer fbuf = GIT_FBUFFER_INIT;
+	git_attr_file *ignores = NULL;
+	git_attr_fnmatch *match = NULL;
+	const char *scan = NULL;
+
+	GIT_UNUSED_ARG(repo);
+
+	*out = NULL;
+
+	if ((error = git_futils_readbuffer(&fbuf, path)) == GIT_SUCCESS)
+		error = git_attr_file__new(&ignores);
+
+	scan = fbuf.data;
+
+	while (error == GIT_SUCCESS && *scan) {
+		if (!match && !(match = git__calloc(1, sizeof(git_attr_fnmatch)))) {
+			error = GIT_ENOMEM;
+			break;
+		}
+
+		if (!(error = git_attr_fnmatch__parse(match, &scan))) {
+			match->flags = match->flags | GIT_ATTR_FNMATCH_IGNORE;
+			scan = git__next_line(scan);
+			error = git_vector_insert(&ignores->rules, match);
+		}
+
+		if (error != GIT_SUCCESS) {
+			git__free(match->pattern);
+			match->pattern = NULL;
+
+			if (error == GIT_ENOTFOUND)
+				error = GIT_SUCCESS;
+		} else {
+			match = NULL; /* vector now "owns" the match */
+		}
+	}
+
+	git_futils_freebuffer(&fbuf);
+
+	if (error != GIT_SUCCESS) {
+		git__rethrow(error, "Could not open ignore file '%s'", path);
+		git__free(match);
+		git_attr_file__free(ignores);
+	} else {
+		*out = ignores;
+	}
+
+	return error;
+}
+
+#define push_ignore(R,S,B,F) \
+	git_attr_cache__push_file((R),(S),(B),(F),load_ignore_file)
+
+int git_ignore__for_path(git_repository *repo, const char *path, git_vector *stack)
+{
+	int error = GIT_SUCCESS;
+	git_buf dir = GIT_BUF_INIT, scan;
+	git_config *cfg;
+	const char *workdir = git_repository_workdir(repo);
+
+	if ((error = git_attr_cache__init(repo)) < GIT_SUCCESS)
+		goto cleanup;
+
+	if ((error = git_futils_dir_for_path(&dir, path, workdir)) < GIT_SUCCESS)
+		goto cleanup;
+
+	/* insert internals */
+	if ((error = push_ignore(repo, stack, NULL, GIT_IGNORE_INTERNAL)) < GIT_SUCCESS)
+		goto cleanup;
+
+	/* load .gitignore up the path */
+	git_path_walk_up(&dir, &scan, workdir, {
+		error = push_ignore(repo, stack, scan.ptr, GIT_IGNORE_FILE);
+		if (error < GIT_SUCCESS) break;
+	});
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	/* load .git/info/exclude */
+	if ((error = push_ignore(repo, stack, repo->path_repository, GIT_IGNORE_FILE_INREPO)) < GIT_SUCCESS)
+		goto cleanup;
+
+	/* load core.excludesfile */
+	if (git_repository_config(&cfg, repo) == GIT_SUCCESS) {
+		const char *core_ignore;
+		error = git_config_get_string(cfg, GIT_IGNORE_CONFIG, &core_ignore);
+		if (error == GIT_SUCCESS && core_ignore != NULL)
+			error = push_ignore(repo, stack, NULL, core_ignore);
+		else {
+			error = GIT_SUCCESS;
+			git_clearerror(); /* don't care if attributesfile is not set */
+		}
+		git_config_free(cfg);
+	}
+
+cleanup:
+	if (error < GIT_SUCCESS)
+		git__rethrow(error, "Could not get ignore files for '%s'", path);
+
+	git_buf_free(&dir);
+
+	return error;
+}
+
+void git_ignore__free(git_vector *stack)
+{
+	git_vector_free(stack);
+}
+
+int git_ignore__lookup(git_vector *stack, const char *pathname, int *ignored)
+{
+	int error;
+	unsigned int i, j;
+	git_attr_file *file;
+	git_attr_path path;
+	git_attr_fnmatch *match;
+
+	if ((error = git_attr_path__init(&path, pathname)) < GIT_SUCCESS)
+		return git__rethrow(error, "Could not get attribute for '%s'", pathname);
+
+	*ignored = 0;
+
+	git_vector_foreach(stack, i, file) {
+		git_vector_rforeach(&file->rules, j, match) {
+			if (git_attr_fnmatch__match(match, &path) == GIT_SUCCESS) {
+				*ignored = ((match->flags & GIT_ATTR_FNMATCH_NEGATIVE) == 0);
+				goto found;
+			}
+		}
+	}
+found:
+
+	return error;
+}
+