Merge pull request #5952 from libgit2/ethomson/attrs_from_commit

Support reading attributes from a specific commit

3 files changed, 149 insertions, 0 deletions

diff --git a/include/git2/attr.h b/include/git2/attr.h
index a3ab5a7a2..62c2ed6e7 100644
--- a/include/git2/attr.h
+++ b/include/git2/attr.h
@@ -130,9 +130,32 @@ GIT_EXTERN(git_attr_value_t) git_attr_value(const char *attr);
  *
  * Passing the `GIT_ATTR_CHECK_INCLUDE_HEAD` flag will use attributes
  * from a `.gitattributes` file in the repository at the HEAD revision.
+ *
+ * Passing the `GIT_ATTR_CHECK_INCLUDE_COMMIT` flag will use attributes
+ * from a `.gitattributes` file in a specific commit.
  */
 #define GIT_ATTR_CHECK_NO_SYSTEM        (1 << 2)
 #define GIT_ATTR_CHECK_INCLUDE_HEAD     (1 << 3)
+#define GIT_ATTR_CHECK_INCLUDE_COMMIT   (1 << 4)
+
+/**
+* An options structure for querying attributes.
+*/
+typedef struct {
+	unsigned int version;
+
+	/** A combination of GIT_ATTR_CHECK flags */
+	unsigned int flags;
+
+	/**
+	 * The commit to load attributes from, when
+	 * `GIT_ATTR_CHECK_INCLUDE_COMMIT` is specified.
+	 */
+	git_oid *commit_id;
+} git_attr_options;
+
+#define GIT_ATTR_OPTIONS_VERSION 1
+#define GIT_ATTR_OPTIONS_INIT {GIT_ATTR_OPTIONS_VERSION}
 
 /**
  * Look up the value of one git attribute for path.
@@ -157,6 +180,28 @@ GIT_EXTERN(int) git_attr_get(
 	const char *name);
 
 /**
+ * Look up the value of one git attribute for path with extended options.
+ *
+ * @param value_out Output of the value of the attribute.  Use the GIT_ATTR_...
+ *             macros to test for TRUE, FALSE, UNSPECIFIED, etc. or just
+ *             use the string value for attributes set to a value.  You
+ *             should NOT modify or free this value.
+ * @param repo The repository containing the path.
+ * @param opts The `git_attr_options` to use when querying these attributes.
+ * @param path The path to check for attributes.  Relative paths are
+ *             interpreted relative to the repo root.  The file does
+ *             not have to exist, but if it does not, then it will be
+ *             treated as a plain file (not a directory).
+ * @param name The name of the attribute to look up.
+ */
+GIT_EXTERN(int) git_attr_get_ext(
+	const char **value_out,
+	git_repository *repo,
+	git_attr_options *opts,
+	const char *path,
+	const char *name);
+
+/**
  * Look up a list of git attributes for path.
  *
  * Use this if you have a known list of attributes that you want to
@@ -194,6 +239,30 @@ GIT_EXTERN(int) git_attr_get_many(
 	const char **names);
 
 /**
+ * Look up a list of git attributes for path with extended options.
+ *
+ * @param values_out An array of num_attr entries that will have string
+ *             pointers written into it for the values of the attributes.
+ *             You should not modify or free the values that are written
+ *             into this array (although of course, you should free the
+ *             array itself if you allocated it).
+ * @param repo The repository containing the path.
+ * @param opts The `git_attr_options` to use when querying these attributes.
+ * @param path The path inside the repo to check attributes.  This
+ *             does not have to exist, but if it does not, then
+ *             it will be treated as a plain file (i.e. not a directory).
+ * @param num_attr The number of attributes being looked up
+ * @param names An array of num_attr strings containing attribute names.
+ */
+GIT_EXTERN(int) git_attr_get_many_ext(
+	const char **values_out,
+	git_repository *repo,
+	git_attr_options *opts,
+	const char *path,
+	size_t num_attr,
+	const char **names);
+
+/**
  * The callback used with git_attr_foreach.
  *
  * This callback will be invoked only once per attribute name, even if there
@@ -232,6 +301,26 @@ GIT_EXTERN(int) git_attr_foreach(
 	void *payload);
 
 /**
+ * Loop over all the git attributes for a path with extended options.
+ *
+ * @param repo The repository containing the path.
+ * @param opts The `git_attr_options` to use when querying these attributes.
+ * @param path Path inside the repo to check attributes.  This does not have
+ *             to exist, but if it does not, then it will be treated as a
+ *             plain file (i.e. not a directory).
+ * @param callback Function to invoke on each attribute name and value.
+ *                 See git_attr_foreach_cb.
+ * @param payload Passed on as extra parameter to callback function.
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_attr_foreach_ext(
+	git_repository *repo,
+	git_attr_options *opts,
+	const char *path,
+	git_attr_foreach_cb callback,
+	void *payload);
+
+/**
  * Flush the gitattributes cache.
  *
  * Call this if you have reason to believe that the attributes files on
diff --git a/include/git2/blob.h b/include/git2/blob.h
index 3f6738675..fceb5c771 100644
--- a/include/git2/blob.h
+++ b/include/git2/blob.h
@@ -114,6 +114,12 @@ typedef enum {
 	 * in the HEAD commit.
 	 */
 	GIT_BLOB_FILTER_ATTRIBUTES_FROM_HEAD = (1 << 2),
+
+	/**
+	 * When set, filters will be loaded from a `.gitattributes` file
+	 * in the specified commit.
+	 */
+	GIT_BLOB_FILTER_ATTRIBUTES_FROM_COMMIT = (1 << 3),
 } git_blob_filter_flag_t;
 
 /**
@@ -128,6 +134,12 @@ typedef struct {
 
 	/** Flags to control the filtering process, see `git_blob_filter_flag_t` above */
 	uint32_t flags;
+
+	/**
+	 * The commit to load attributes from, when
+	 * `GIT_BLOB_FILTER_ATTRIBUTES_FROM_COMMIT` is specified.
+	 */
+	git_oid *commit_id;
 } git_blob_filter_options;
 
 #define GIT_BLOB_FILTER_OPTIONS_VERSION 1
diff --git a/include/git2/filter.h b/include/git2/filter.h
index a0185ee88..044c3b870 100644
--- a/include/git2/filter.h
+++ b/include/git2/filter.h
@@ -49,9 +49,34 @@ typedef enum {
 
 	/** Load attributes from `.gitattributes` in the root of HEAD */
 	GIT_FILTER_ATTRIBUTES_FROM_HEAD = (1u << 2),
+
+	/**
+	 * Load attributes from `.gitattributes` in a given commit.
+	 * This can only be specified in a `git_filter_options`.
+	 */
+	GIT_FILTER_ATTRIBUTES_FROM_COMMIT = (1u << 3),
 } git_filter_flag_t;
 
 /**
+ * Filtering options
+ */
+typedef struct {
+	unsigned int version;
+
+	/** See `git_filter_flag_t` above */
+	uint32_t flags;
+
+	/**
+	 * The commit to load attributes from, when
+	 * `GIT_FILTER_ATTRIBUTES_FROM_COMMIT` is specified.
+	 */
+	git_oid *commit_id;
+} git_filter_options;
+
+ #define GIT_FILTER_OPTIONS_VERSION 1
+ #define GIT_FILTER_OPTIONS_INIT {GIT_FILTER_OPTIONS_VERSION}
+
+/**
  * A filter that can transform file data
  *
  * This represents a filter that can be used to transform or even replace
@@ -104,6 +129,29 @@ GIT_EXTERN(int) git_filter_list_load(
 	uint32_t flags);
 
 /**
+ * Load the filter list for a given path.
+ *
+ * This will return 0 (success) but set the output git_filter_list to NULL
+ * if no filters are requested for the given file.
+ *
+ * @param filters Output newly created git_filter_list (or NULL)
+ * @param repo Repository object that contains `path`
+ * @param blob The blob to which the filter will be applied (if known)
+ * @param path Relative path of the file to be filtered
+ * @param mode Filtering direction (WT->ODB or ODB->WT)
+ * @param opts The `git_filter_options` to use when loading filters
+ * @return 0 on success (which could still return NULL if no filters are
+ *         needed for the requested file), <0 on error
+ */
+GIT_EXTERN(int) git_filter_list_load_ext(
+	git_filter_list **filters,
+	git_repository *repo,
+	git_blob *blob,
+	const char *path,
+	git_filter_mode_t mode,
+	git_filter_options *opts);
+
+/**
  * Query the filter list to see if a given filter (by name) will run.
  * The built-in filters "crlf" and "ident" can be queried, otherwise this
  * is the name of the filter specified by the filter attribute.