Introduce GIT_CALLBACK macro to enforce cdecl

Since we now always build the library with cdecl calling conventions,
our callbacks should be decorated as such so that users will not be able
to provide callbacks defined with other calling conventions.

The `GIT_CALLBACK` macro will inject the `__cdecl` attribute as
appropriate.

Author: ethomson

include/git2/apply.h

@@ -33,7 +33,7 @@ GIT_BEGIN_DECL
  * @param delta The delta to be applied
  * @param payload User-specified payload
  */
-typedef int (*git_apply_delta_cb)(
+typedef int GIT_CALLBACK(git_apply_delta_cb)(
 	const git_diff_delta *delta,
 	void *payload);
 
@@ -49,7 +49,7 @@ typedef int (*git_apply_delta_cb)(
  * @param hunk The hunk to be applied
  * @param payload User-specified payload
  */
-typedef int (*git_apply_hunk_cb)(
+typedef int GIT_CALLBACK(git_apply_hunk_cb)(
 	const git_diff_hunk *hunk,
 	void *payload);
 

include/git2/attr.h

@@ -202,7 +202,7 @@ GIT_EXTERN(int) git_attr_get_many(
  * @return 0 to continue looping, non-zero to stop. This value will be returned
  *         from git_attr_foreach.
  */
-typedef int (*git_attr_foreach_cb)(const char *name, const char *value, void *payload);
+typedef int GIT_CALLBACK(git_attr_foreach_cb)(const char *name, const char *value, void *payload);
 
 /**
  * Loop over all the git attributes for a path.

include/git2/checkout.h

@@ -220,7 +220,7 @@ typedef struct {
 } git_checkout_perfdata;
 
 /** Checkout notification callback function */
-typedef int (*git_checkout_notify_cb)(
+typedef int GIT_CALLBACK(git_checkout_notify_cb)(
 	git_checkout_notify_t why,
 	const char *path,
 	const git_diff_file *baseline,
@@ -229,14 +229,14 @@ typedef int (*git_checkout_notify_cb)(
 	void *payload);
 
 /** Checkout progress notification function */
-typedef void (*git_checkout_progress_cb)(
+typedef void GIT_CALLBACK(git_checkout_progress_cb)(
 	const char *path,
 	size_t completed_steps,
 	size_t total_steps,
 	void *payload);
 
 /** Checkout perfdata notification function */
-typedef void (*git_checkout_perfdata_cb)(
+typedef void GIT_CALLBACK(git_checkout_perfdata_cb)(
 	const git_checkout_perfdata *perfdata,
 	void *payload);
 

include/git2/clone.h

@@ -66,7 +66,7 @@ typedef enum {
  * @param payload an opaque payload
  * @return 0, GIT_EINVALIDSPEC, GIT_EEXISTS or an error code
  */
-typedef int (*git_remote_create_cb)(
+typedef int GIT_CALLBACK(git_remote_create_cb)(
 	git_remote **out,
 	git_repository *repo,
 	const char *name,
@@ -87,7 +87,7 @@ typedef int (*git_remote_create_cb)(
  * @param payload payload specified by the options
  * @return 0, or a negative value to indicate error
  */
-typedef int (*git_repository_create_cb)(
+typedef int GIT_CALLBACK(git_repository_create_cb)(
 	git_repository **out,
 	const char *path,
 	int bare,

include/git2/common.h

@@ -48,6 +48,13 @@ typedef size_t size_t;
 # define GIT_EXTERN(type) extern type
 #endif
 
+/** Declare a callback function for application use. */
+#if defined(_MSC_VER)
+# define GIT_CALLBACK(name) (__cdecl *name)
+#else
+# define GIT_CALLBACK(name) (*name)
+#endif
+
 /** Declare a function as deprecated. */
 #if defined(__GNUC__)
 # define GIT_DEPRECATED(func) \

include/git2/config.h

@@ -66,7 +66,7 @@ typedef struct git_config_entry {
 	const char *value; /**< String value of the entry */
 	unsigned int include_depth; /**< Depth of includes where this variable was found */
 	git_config_level_t level; /**< Which config file this was found in */
-	void (*free)(struct git_config_entry *entry); /**< Free function for this entry */
+	void GIT_CALLBACK(free)(struct git_config_entry *entry); /**< Free function for this entry */
 	void *payload; /**< Opaque value for the free function. Do not read or write */
 } git_config_entry;
 
@@ -81,7 +81,7 @@ GIT_EXTERN(void) git_config_entry_free(git_config_entry *);
  * @param entry the entry currently being enumerated
  * @param payload a user-specified pointer
  */
-typedef int  (*git_config_foreach_cb)(const git_config_entry *entry, void *payload);
+typedef int GIT_CALLBACK(git_config_foreach_cb)(const git_config_entry *entry, void *payload);
 
 /**
  * An opaque structure for a configuration iterator

include/git2/diff.h

@@ -328,7 +328,7 @@ typedef struct {
  * - returns 0, the delta is inserted into the diff, and the diff process
  *		continues.
  */
-typedef int (*git_diff_notify_cb)(
+typedef int GIT_CALLBACK(git_diff_notify_cb)(
 	const git_diff *diff_so_far,
 	const git_diff_delta *delta_to_add,
 	const char *matched_pathspec,
@@ -344,7 +344,7 @@ typedef int (*git_diff_notify_cb)(
  * @param new_path The path to the new file or NULL.
  * @return Non-zero to abort the diff.
  */
-typedef int (*git_diff_progress_cb)(
+typedef int GIT_CALLBACK(git_diff_progress_cb)(
 	const git_diff *diff_so_far,
 	const char *old_path,
 	const char *new_path,
@@ -462,7 +462,7 @@ GIT_EXTERN(int) git_diff_init_options(
  * @param progress Goes from 0 to 1 over the diff
  * @param payload User-specified pointer from foreach function
  */
-typedef int (*git_diff_file_cb)(
+typedef int GIT_CALLBACK(git_diff_file_cb)(
 	const git_diff_delta *delta,
 	float progress,
 	void *payload);
@@ -528,7 +528,7 @@ typedef struct {
  * When iterating over a diff, callback that will be made for
  * binary content within the diff.
  */
-typedef int(*git_diff_binary_cb)(
+typedef int GIT_CALLBACK(git_diff_binary_cb)(
 	const git_diff_delta *delta,
 	const git_diff_binary *binary,
 	void *payload);
@@ -554,7 +554,7 @@ typedef struct {
 /**
  * When iterating over a diff, callback that will be made per hunk.
  */
-typedef int (*git_diff_hunk_cb)(
+typedef int GIT_CALLBACK(git_diff_hunk_cb)(
 	const git_diff_delta *delta,
 	const git_diff_hunk *hunk,
 	void *payload);
@@ -615,7 +615,7 @@ typedef struct {
  * of text.  This uses some extra GIT_DIFF_LINE_... constants for output
  * of lines of file and hunk headers.
  */
-typedef int (*git_diff_line_cb)(
+typedef int GIT_CALLBACK(git_diff_line_cb)(
 	const git_diff_delta *delta, /**< delta that contains this data */
 	const git_diff_hunk *hunk,   /**< hunk containing this data */
 	const git_diff_line *line,   /**< line data */
@@ -699,14 +699,14 @@ typedef enum {
  * Pluggable similarity metric
  */
 typedef struct {
-	int (*file_signature)(
+	int GIT_CALLBACK(file_signature)(
 		void **out, const git_diff_file *file,
 		const char *fullpath, void *payload);
-	int (*buffer_signature)(
+	int GIT_CALLBACK(buffer_signature)(
 		void **out, const git_diff_file *file,
 		const char *buf, size_t buflen, void *payload);
-	void (*free_signature)(void *sig, void *payload);
-	int (*similarity)(int *score, void *siga, void *sigb, void *payload);
+	void GIT_CALLBACK(free_signature)(void *sig, void *payload);
+	int GIT_CALLBACK(similarity)(int *score, void *siga, void *sigb, void *payload);
 	void *payload;
 } git_diff_similarity_metric;
 

include/git2/index.h

@@ -132,7 +132,7 @@ typedef enum {
 
 
 /** Callback for APIs that add/remove/update files matching pathspec */
-typedef int (*git_index_matched_path_cb)(
+typedef int GIT_CALLBACK(git_index_matched_path_cb)(
 	const char *path, const char *matched_pathspec, void *payload);
 
 /** Flags for APIs that add files matching pathspec */

include/git2/net.h

@@ -52,7 +52,7 @@ struct git_remote_head {
 /**
  * Callback for listing the remote heads
  */
-typedef int (*git_headlist_cb)(git_remote_head *rhead, void *payload);
+typedef int GIT_CALLBACK(git_headlist_cb)(git_remote_head *rhead, void *payload);
 
 /** @} */
 GIT_END_DECL

include/git2/notes.h

@@ -26,7 +26,7 @@ GIT_BEGIN_DECL
  * - annotated_object_id: Oid of the git object being annotated
  * - payload: Payload data passed to `git_note_foreach`
  */
-typedef int (*git_note_foreach_cb)(
+typedef int GIT_CALLBACK(git_note_foreach_cb)(
 	const git_oid *blob_id, const git_oid *annotated_object_id, void *payload);
 
 /**

include/git2/odb.h

@@ -24,7 +24,7 @@ GIT_BEGIN_DECL
 /**
  * Function type for callbacks from git_odb_foreach.
  */
-typedef int (*git_odb_foreach_cb)(const git_oid *id, void *payload);
+typedef int GIT_CALLBACK(git_odb_foreach_cb)(const git_oid *id, void *payload);
 
 /**
  * Create a new object database with no backends.

include/git2/odb_backend.h

@@ -92,12 +92,12 @@ struct git_odb_stream {
 	/**
 	 * Write at most `len` bytes into `buffer` and advance the stream.
 	 */
-	int (*read)(git_odb_stream *stream, char *buffer, size_t len);
+	int GIT_CALLBACK(read)(git_odb_stream *stream, char *buffer, size_t len);
 
 	/**
 	 * Write `len` bytes from `buffer` into the stream.
 	 */
-	int (*write)(git_odb_stream *stream, const char *buffer, size_t len);
+	int GIT_CALLBACK(write)(git_odb_stream *stream, const char *buffer, size_t len);
 
 	/**
 	 * Store the contents of the stream as an object with the id
@@ -109,24 +109,24 @@ struct git_odb_stream {
 	 * - the final number of received bytes differs from the size declared
 	 *   with `git_odb_open_wstream()`
 	 */
-	int (*finalize_write)(git_odb_stream *stream, const git_oid *oid);
+	int GIT_CALLBACK(finalize_write)(git_odb_stream *stream, const git_oid *oid);
 
 	/**
 	 * Free the stream's memory.
 	 *
 	 * This method might be called without a call to `finalize_write` if
 	 * an error occurs or if the object is already present in the ODB.
 	 */
-	void (*free)(git_odb_stream *stream);
+	void GIT_CALLBACK(free)(git_odb_stream *stream);
 };
 
 /** A stream to write a pack file to the ODB */
 struct git_odb_writepack {
 	git_odb_backend *backend;
 
-	int (*append)(git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
-	int (*commit)(git_odb_writepack *writepack, git_transfer_progress *stats);
-	void (*free)(git_odb_writepack *writepack);
+	int GIT_CALLBACK(append)(git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
+	int GIT_CALLBACK(commit)(git_odb_writepack *writepack, git_transfer_progress *stats);
+	void GIT_CALLBACK(free)(git_odb_writepack *writepack);
 };
 
 GIT_END_DECL

include/git2/pack.h

@@ -178,7 +178,7 @@ GIT_EXTERN(int) git_packbuilder_write(
 */
 GIT_EXTERN(const git_oid *) git_packbuilder_hash(git_packbuilder *pb);
 
-typedef int (*git_packbuilder_foreach_cb)(void *buf, size_t size, void *payload);
+typedef int GIT_CALLBACK(git_packbuilder_foreach_cb)(void *buf, size_t size, void *payload);
 
 /**
  * Create the new pack and pass each object to the callback
@@ -207,7 +207,7 @@ GIT_EXTERN(size_t) git_packbuilder_object_count(git_packbuilder *pb);
 GIT_EXTERN(size_t) git_packbuilder_written(git_packbuilder *pb);
 
 /** Packbuilder progress notification function */
-typedef int (*git_packbuilder_progress)(
+typedef int GIT_CALLBACK(git_packbuilder_progress)(
 	int stage,
 	uint32_t current,
 	uint32_t total,

include/git2/refs.h

@@ -422,8 +422,8 @@ GIT_EXTERN(int) git_reference_remove(git_repository *repo, const char *name);
  */
 GIT_EXTERN(int) git_reference_list(git_strarray *array, git_repository *repo);
 
-typedef int (*git_reference_foreach_cb)(git_reference *reference, void *payload);
-typedef int (*git_reference_foreach_name_cb)(const char *name, void *payload);
+typedef int GIT_CALLBACK(git_reference_foreach_cb)(git_reference *reference, void *payload);
+typedef int GIT_CALLBACK(git_reference_foreach_name_cb)(const char *name, void *payload);
 
 /**
  * Perform a callback on each reference in the repository.

include/git2/remote.h

@@ -422,7 +422,7 @@ typedef enum git_remote_completion_type {
 } git_remote_completion_type;
 
 /** Push network progress notification function */
-typedef int (*git_push_transfer_progress)(
+typedef int GIT_CALLBACK(git_push_transfer_progress)(
 	unsigned int current,
 	unsigned int total,
 	size_t bytes,
@@ -457,7 +457,7 @@ typedef struct {
  * @param len number of elements in `updates`
  * @param payload Payload provided by the caller
  */
-typedef int (*git_push_negotiation)(const git_push_update **updates, size_t len, void *payload);
+typedef int GIT_CALLBACK(git_push_negotiation)(const git_push_update **updates, size_t len, void *payload);
 
 /**
  * Callback used to inform of the update status from the remote.
@@ -471,7 +471,7 @@ typedef int (*git_push_negotiation)(const git_push_update **updates, size_t len,
  * @param data data provided by the caller
  * @return 0 on success, otherwise an error
  */
-typedef int (*git_push_update_reference_cb)(const char *refname, const char *status, void *data);
+typedef int GIT_CALLBACK(git_push_update_reference_cb)(const char *refname, const char *status, void *data);
 
 /**
  * The callback settings structure
@@ -492,7 +492,7 @@ struct git_remote_callbacks {
 	 * Completion is called when different parts of the download
 	 * process are done (currently unused).
 	 */
-	int (*completion)(git_remote_completion_type type, void *data);
+	int GIT_CALLBACK(completion)(git_remote_completion_type type, void *data);
 
 	/**
 	 * This will be called if the remote host requires
@@ -522,7 +522,7 @@ struct git_remote_callbacks {
 	 * Each time a reference is updated locally, this function
 	 * will be called with information about it.
 	 */
-	int (*update_tips)(const char *refname, const git_oid *a, const git_oid *b, void *data);
+	int GIT_CALLBACK(update_tips)(const char *refname, const git_oid *a, const git_oid *b, void *data);
 
 	/**
 	 * Function to call with progress information during pack

include/git2/repository.h

@@ -627,7 +627,7 @@ GIT_EXTERN(int) git_repository_message_remove(git_repository *repo);
  */
 GIT_EXTERN(int) git_repository_state_cleanup(git_repository *repo);
 
-typedef int (*git_repository_fetchhead_foreach_cb)(const char *ref_name,
+typedef int GIT_CALLBACK(git_repository_fetchhead_foreach_cb)(const char *ref_name,
 	const char *remote_url,
 	const git_oid *oid,
 	unsigned int is_merge,
@@ -649,7 +649,7 @@ GIT_EXTERN(int) git_repository_fetchhead_foreach(
 	git_repository_fetchhead_foreach_cb callback,
 	void *payload);
 
-typedef int (*git_repository_mergehead_foreach_cb)(const git_oid *oid,
+typedef int GIT_CALLBACK(git_repository_mergehead_foreach_cb)(const git_oid *oid,
 	void *payload);
 
 /**

include/git2/revwalk.h

@@ -274,7 +274,7 @@ GIT_EXTERN(git_repository *) git_revwalk_repository(git_revwalk *walk);
  * @param commit_id oid of Commit
  * @param payload User-specified pointer to data to be passed as data payload
  */
-typedef int(*git_revwalk_hide_cb)(
+typedef int GIT_CALLBACK(git_revwalk_hide_cb)(
 	const git_oid *commit_id,
 	void *payload);
 

include/git2/stash.h

@@ -112,7 +112,7 @@ typedef enum {
  * Return 0 to continue processing, or a negative value to
  * abort the stash application.
  */
-typedef int (*git_stash_apply_progress_cb)(
+typedef int GIT_CALLBACK(git_stash_apply_progress_cb)(
 	git_stash_apply_progress_t progress,
 	void *payload);
 
@@ -198,7 +198,7 @@ GIT_EXTERN(int) git_stash_apply(
  * @param payload Extra parameter to callback function.
  * @return 0 to continue iterating or non-zero to stop.
  */
-typedef int (*git_stash_cb)(
+typedef int GIT_CALLBACK(git_stash_cb)(
 	size_t index,
 	const char* message,
 	const git_oid *stash_id,

include/git2/status.h

@@ -60,7 +60,7 @@ typedef enum {
  *
  * `payload` is the value you passed to the foreach function as payload.
  */
-typedef int (*git_status_cb)(
+typedef int GIT_CALLBACK(git_status_cb)(
 	const char *path, unsigned int status_flags, void *payload);
 
 /**

include/git2/submodule.h

@@ -115,7 +115,7 @@ typedef enum {
  * @param payload value you passed to the foreach function as payload
  * @return 0 on success or error code
  */
-typedef int (*git_submodule_cb)(
+typedef int GIT_CALLBACK(git_submodule_cb)(
 	git_submodule *sm, const char *name, void *payload);
 
 /**