Commit d6c6016966cff46d874a8d85b38704a6ef2150e5

Russell Belfer 2013-11-04T15:45:31

Add giterr_detach API to get and clear error There are a number of cases where it is convenient to be able to fetch and "claim" the current error string, clearing the error. This is helpful when you need to call some code that may alter the error and you want to restore it later on and/or report it via some other mechanism.

diff --git a/include/git2/errors.h b/include/git2/errors.h
index a454ac9..5f5d0ab 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -8,6 +8,7 @@
 #define INCLUDE_git_errors_h__
 
 #include "common.h"
+#include "buffer.h"
 
 /**
  * @file git2/errors.h
@@ -45,6 +46,7 @@ typedef struct {
 
 /** Error classes */
 typedef enum {
+	GITERR_NONE = 0,
 	GITERR_NOMEMORY,
 	GITERR_OS,
 	GITERR_INVALID,
@@ -85,6 +87,21 @@ GIT_EXTERN(const git_error *) giterr_last(void);
 GIT_EXTERN(void) giterr_clear(void);
 
 /**
+ * Get the last error data and clear it.
+ *
+ * This copies the last error message into the given `git_buf` and returns
+ * the associated `git_error_t`, leaving the error cleared as if
+ * `giterr_clear` had been called.  You must call `git_buf_free` on the
+ * message to release the memory.
+ *
+ * Note: it is possible that this will return `GITERR_NONE` and set the
+ * buffer to NULL, so be prepared for that condition.  Also, if the last
+ * error was an out-of-memory error, this will return `GITERR_NOMEMORY`
+ * but also leave the buffer set to NULL (to avoid allocation).
+ */
+GIT_EXTERN(git_error_t) giterr_detach(git_buf *message);
+
+/**
  * Set the error message string for this thread.
  *
  * This function is public so that custom ODB backends and the like can
diff --git a/src/errors.c b/src/errors.c
index c9d9e4e..70b5f26 100644
--- a/src/errors.c
+++ b/src/errors.c
@@ -112,6 +112,29 @@ void giterr_clear(void)
 #endif
 }
 
+git_error_t giterr_detach(git_buf *message)
+{
+	git_error_t rval;
+	git_error *error = GIT_GLOBAL->last_error;
+
+	assert(message);
+
+	git_buf_free(message);
+
+	if (!error)
+		return GITERR_NONE;
+
+	rval = error->klass;
+
+	if (error != &g_git_oom_error)
+		git_buf_attach(message, error->message, 0);
+
+	error->message = NULL;
+	giterr_clear();
+
+	return rval;
+}
+
 const git_error *giterr_last(void)
 {
 	return GIT_GLOBAL->last_error;