Add filter options and ALLOW_UNSAFE

Diff and status do not want core.safecrlf to actually raise an
error regardless of the setting, so this extends the filter API
with an additional options flags parameter and adds a flag so that
filters can be applied with GIT_FILTER_OPT_ALLOW_UNSAFE, indicating
that unsafe filter application should be downgraded from a failure
to a warning.

3 files changed, 22 insertions, 3 deletions

diff --git a/include/git2/filter.h b/include/git2/filter.h
index f96b6766b..7fd9b7e59 100644
--- a/include/git2/filter.h
+++ b/include/git2/filter.h
@@ -35,6 +35,11 @@ typedef enum {
 	GIT_FILTER_CLEAN = GIT_FILTER_TO_ODB,
 } git_filter_mode_t;
 
+typedef enum {
+	GIT_FILTER_OPT_DEFAULT = 0u,
+	GIT_FILTER_OPT_ALLOW_UNSAFE = (1u << 0),
+} git_filter_opt_t;
+
 /**
  * A filter that can transform file data
  *
@@ -83,7 +88,8 @@ GIT_EXTERN(int) git_filter_list_load(
 	git_repository *repo,
 	git_blob *blob, /* can be NULL */
 	const char *path,
-	git_filter_mode_t mode);
+	git_filter_mode_t mode,
+	git_filter_opt_t options);
 
 /**
  * Apply filter list to a data buffer.
diff --git a/include/git2/repository.h b/include/git2/repository.h
index e3f687a29..04df25fd3 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -546,6 +546,10 @@ GIT_EXTERN(int) git_repository_mergehead_foreach(
  * hash a file in the repository and you want to apply filtering rules (e.g.
  * crlf filters) before generating the SHA, then use this function.
  *
+ * Note: if the repository has `core.safecrlf` set to fail and the
+ * filtering triggers that failure, then this function will return an
+ * error and not calculate the hash of the file.
+ *
  * @param out Output value of calculated SHA
  * @param repo Repository pointer
  * @param path Path to file on disk whose contents should be hashed. If the
@@ -555,6 +559,7 @@ GIT_EXTERN(int) git_repository_mergehead_foreach(
  *             NULL, then the `path` parameter will be used instead. If
  *             this is passed as the empty string, then no filters will be
  *             applied when calculating the hash.
+ * @return 0 on success, or an error code
  */
 GIT_EXTERN(int) git_repository_hashfile(
 	git_oid *out,
diff --git a/include/git2/sys/filter.h b/include/git2/sys/filter.h
index 8fe21c9c0..1b21a9d30 100644
--- a/include/git2/sys/filter.h
+++ b/include/git2/sys/filter.h
@@ -55,7 +55,10 @@ GIT_EXTERN(git_filter *) git_filter_lookup(const char *name);
  * your own chains of filters.
  */
 GIT_EXTERN(int) git_filter_list_new(
-	git_filter_list **out, git_repository *repo, git_filter_mode_t mode);
+	git_filter_list **out,
+	git_repository *repo,
+	git_filter_mode_t mode,
+	git_filter_opt_t options);
 
 /**
  * Add a filter to a filter list with the given payload.
@@ -115,10 +118,15 @@ GIT_EXTERN(uint16_t) git_filter_source_filemode(const git_filter_source *src);
 GIT_EXTERN(const git_oid *) git_filter_source_id(const git_filter_source *src);
 
 /**
- * Get the git_filter_mode_t to be applied
+ * Get the git_filter_mode_t to be used
  */
 GIT_EXTERN(git_filter_mode_t) git_filter_source_mode(const git_filter_source *src);
 
+/**
+ * Get the git_filter_opt_t options to be applied
+ */
+GIT_EXTERN(git_filter_opt_t) git_filter_source_options(const git_filter_source *src);
+
 /*
  * struct git_filter
  *