Support reading attributes from index

Depending on the operation, we need to consider gitattributes
in both the work dir and the index.  This adds a parameter to
all of the gitattributes related functions that allows user
control of attribute reading behavior (i.e. prefer workdir,
prefer index, only use index).

This fix also covers allowing us to check attributes (and
hence do diff and status) on bare repositories.

This was a somewhat larger change that I hoped because it had
to change the cache key used for gitattributes files.

1 files changed, 44 insertions, 46 deletions

diff --git a/src/attr_file.c b/src/attr_file.c
index 25c21b1fd..ab320a6c4 100644
--- a/src/attr_file.c
+++ b/src/attr_file.c
@@ -1,15 +1,22 @@
 #include "common.h"
 #include "repository.h"
 #include "filebuf.h"
+#include "git2/blob.h"
+#include "git2/tree.h"
 #include <ctype.h>
 
 const char *git_attr__true  = "[internal]__TRUE__";
 const char *git_attr__false = "[internal]__FALSE__";
+const char *git_attr__unset = "[internal]__UNSET__";
 
 static int sort_by_hash_and_name(const void *a_raw, const void *b_raw);
 static void git_attr_rule__clear(git_attr_rule *rule);
 
-int git_attr_file__new(git_attr_file **attrs_ptr, git_pool *pool)
+int git_attr_file__new(
+	git_attr_file **attrs_ptr,
+	git_attr_file_source from,
+	const char *path,
+	git_pool *pool)
 {
 	git_attr_file *attrs = NULL;
 
@@ -25,6 +32,18 @@ int git_attr_file__new(git_attr_file **attrs_ptr, git_pool *pool)
 		attrs->pool_is_allocated = true;
 	}
 
+	if (path) {
+		size_t len = strlen(path);
+
+		attrs->key = git_pool_malloc(attrs->pool, len + 3);
+		GITERR_CHECK_ALLOC(attrs->key);
+
+		attrs->key[0] = '0' + from;
+		attrs->key[1] = '#';
+		memcpy(&attrs->key[2], path, len);
+		attrs->key[len + 2] = '\0';
+	}
+
 	if (git_vector_init(&attrs->rules, 4, NULL) < 0)
 		goto fail;
 
@@ -37,31 +56,7 @@ fail:
 	return -1;
 }
 
-int git_attr_file__set_path(
-	git_repository *repo, const char *path, git_attr_file *file)
-{
-	if (file->path != NULL) {
-		git__free(file->path);
-		file->path = NULL;
-	}
-
-	if (repo == NULL)
-		file->path = git__strdup(path);
-	else {
-		const char *workdir = git_repository_workdir(repo);
-
-		if (workdir && git__prefixcmp(path, workdir) == 0)
-			file->path = git__strdup(path + strlen(workdir));
-		else
-			file->path = git__strdup(path);
-	}
-
-	GITERR_CHECK_ALLOC(file->path);
-
-	return 0;
-}
-
-int git_attr_file__from_buffer(
+int git_attr_file__parse_buffer(
 	git_repository *repo, const char *buffer, git_attr_file *attrs)
 {
 	int error = 0;
@@ -73,10 +68,10 @@ int git_attr_file__from_buffer(
 
 	scan = buffer;
 
-	if (attrs->path && git__suffixcmp(attrs->path, GIT_ATTR_FILE) == 0) {
-		context = git__strndup(attrs->path,
-			strlen(attrs->path) - strlen(GIT_ATTR_FILE));
-		GITERR_CHECK_ALLOC(context);
+	/* if subdir file path, convert context for file paths */
+	if (attrs->key && git__suffixcmp(attrs->key, "/" GIT_ATTR_FILE) == 0) {
+		context = attrs->key + 2;
+		context[strlen(context) - strlen(GIT_ATTR_FILE)] = '\0';
 	}
 
 	while (!error && *scan) {
@@ -112,28 +107,34 @@ int git_attr_file__from_buffer(
 	}
 
 	git_attr_rule__free(rule);
-	git__free(context);
+
+	/* restore file path used for context */
+	if (context)
+		context[strlen(context)] = '.'; /* first char of GIT_ATTR_FILE */
 
 	return error;
 }
 
-int git_attr_file__from_file(
-	git_repository *repo, const char *path, git_attr_file *file)
+int git_attr_file__new_and_load(
+	git_attr_file **attrs_ptr,
+	const char *path)
 {
 	int error;
-	git_buf fbuf = GIT_BUF_INIT;
+	git_buf content = GIT_BUF_INIT;
 
-	assert(path && file);
+	if ((error = git_attr_file__new(attrs_ptr, 0, path, NULL)) < 0)
+		return error;
 
-	if (file->path == NULL && git_attr_file__set_path(repo, path, file) < 0)
-		return -1;
-
-	if (git_futils_readbuffer(&fbuf, path) < 0)
-		return -1;
+	if (!(error = git_futils_readbuffer(&content, path)))
+		error = git_attr_file__parse_buffer(
+			NULL, git_buf_cstr(&content), *attrs_ptr);
 
-	error = git_attr_file__from_buffer(repo, fbuf.ptr, file);
+	git_buf_free(&content);
 
-	git_buf_free(&fbuf);
+	if (error) {
+		git_attr_file__free(*attrs_ptr);
+		*attrs_ptr = NULL;
+	}
 
 	return error;
 }
@@ -151,9 +152,6 @@ void git_attr_file__free(git_attr_file *file)
 
 	git_vector_free(&file->rules);
 
-	git__free(file->path);
-	file->path = NULL;
-
 	if (file->pool_is_allocated) {
 		git_pool_clear(file->pool);
 		git__free(file->pool);
@@ -504,7 +502,7 @@ int git_attr_assignment__parse(
 			assign->value = git_attr__false;
 			scan++;
 		} else if (*scan == '!') {
-			assign->value = NULL; /* explicit unspecified state */
+			assign->value = git_attr__unset; /* explicit unspecified state */
 			scan++;
 		} else if (*scan == '#') /* comment rest of line */
 			break;