Set cancellations as active for the current thread

4 files changed, 80 insertions, 2 deletions

diff --git a/include/git2/cancellation.h b/include/git2/cancellation.h
index 8c5964697..2223b1784 100644
--- a/include/git2/cancellation.h
+++ b/include/git2/cancellation.h
@@ -72,4 +72,32 @@ GIT_EXTERN(int) git_cancellation_register(git_cancellation *c, git_cancellation_
  */
 GIT_EXTERN(int) git_cancellation_request(git_cancellation *c);
 
+/**
+ * Activate the cancellation for this thread
+ *
+ * Put the cancellation structure in thread-local storage where the next public
+ * function which supports cancellations can make use of it. This overwrites any
+ * cancellation that is currently active.
+ *
+ * The ownership of the cancellation moves to the library. Do not free its
+ * memory after calling this function.
+ *
+ * @param c the cancellation to activate
+ * @return 0
+ */
+GIT_EXTERN(int) git_cancellation_activate(git_cancellation *c);
+
+/**
+ * Deactivate the current cancellation for this thread
+ *
+ * If there is a cancellation set for this thread, remove it from thread-local
+ * storage and free it.
+ *
+ * You can use this after calling into the library to make sure there are no
+ * spurious cancellation triggers.
+ *
+ * @return 0
+ */
+GIT_EXTERN(int) git_cancellation_deactivate(void);
+
 #endif
diff --git a/src/cancellation.c b/src/cancellation.c
index eac200804..62e49ba83 100644
--- a/src/cancellation.c
+++ b/src/cancellation.c
@@ -6,16 +6,17 @@
  */
 
 #include "common.h"
+#include "global.h"
 #include "array.h"
 
-#include "git2/cancellation.h"
+#include "cancellation.h"
 
 typedef struct {
 	git_cancellation_cb cb;
 	void *payload;
 } registration;
 
-struct  git_cancellation {
+struct git_cancellation {
 	/* Lock over the whole structure */
 	git_mutex lock;
 	git_array_t(registration) registrations;
@@ -117,3 +118,23 @@ int git_cancellation_request(git_cancellation *c)
 	git_mutex_unlock(&c->lock);
 	return error;
 }
+
+int git_cancellation_activate(git_cancellation *c)
+{
+	git_cancellation *old;
+
+	old = git__swap(GIT_GLOBAL->cancellation, c);
+
+	git_cancellation_free(old);
+	return 0;
+}
+
+int git_cancellation_deactivate(void)
+{
+	git_cancellation *old;
+
+	old = git__swap(GIT_GLOBAL->cancellation, NULL);
+
+	git_cancellation_free(old);
+	return 0;
+}
diff --git a/src/cancellation.h b/src/cancellation.h
new file mode 100644
index 000000000..d447e00c6
--- /dev/null
+++ b/src/cancellation.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_cancellation_h__
+#define INCLUDE_cancellation_h__
+
+#include "git2/cancellation.h"
+
+#include "global.h"
+
+/**
+ * Check whether there's an active cancellation that's been canceled.
+ */
+GIT_INLINE(bool) git_cancellation__cancelled(void)
+{
+	git_cancellation *c = GIT_GLOBAL->cancellation;
+
+	if (!c)
+		return false;
+
+	return git_cancellation_requested(c);
+}
+
+#endif
diff --git a/src/global.h b/src/global.h
index 219951525..30a616f98 100644
--- a/src/global.h
+++ b/src/global.h
@@ -10,12 +10,14 @@
 #include "common.h"
 #include "mwindow.h"
 #include "hash.h"
+#include "git2/cancellation.h"
 
 typedef struct {
 	git_error *last_error;
 	git_error error_t;
 	git_buf error_buf;
 	char oid_fmt[GIT_OID_HEXSZ+1];
+	git_cancellation *cancellation;
 } git_global_st;
 
 #ifdef GIT_OPENSSL