Refactor the pipe/eventfd abstraction

This introduces the wakeup fd interface, corresponding approximately to
the existing Google version, complete with a ported giant detailed usage
comment.

The implementation has two layers, "specialized" and "fallback". The
specialized layer is intended to be a suitable platform specific
implementation like eventfd, whereas "fallback" is probably pipe, with
runtime detection of whether the specialized version works on this
system (currently stubbed out).

1 files changed, 16 insertions, 10 deletions

diff --git a/src/core/iomgr/pollset_kick.h b/src/core/iomgr/pollset_kick.h
index 4459a31b4f..5e90931261 100644
--- a/src/core/iomgr/pollset_kick.h
+++ b/src/core/iomgr/pollset_kick.h
@@ -34,27 +34,33 @@
 #ifndef __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
 #define __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
 
-#include <grpc/support/port_platform.h>
+#include "src/core/iomgr/wakeup_fd.h"
+#include <grpc/support/sync.h>
 
 /* This is an abstraction around the typical pipe mechanism for waking up a
    thread sitting in a poll() style call. */
 
-#ifdef GPR_POSIX_SOCKET
-#include "src/core/iomgr/pollset_kick_posix.h"
-#else
-#error "No pollset kick support on platform"
-#endif
+typedef struct grpc_kick_fd_info {
+  grpc_wakeup_fd_info wakeup_fd;
+  struct grpc_kick_fd_info *next;
+} grpc_kick_fd_info;
+
+typedef struct grpc_pollset_kick_state {
+  gpr_mu mu;
+  int kicked;
+  struct grpc_kick_fd_info *fd_info;
+} grpc_pollset_kick_state;
 
 void grpc_pollset_kick_global_init(void);
 void grpc_pollset_kick_global_destroy(void);
 
-/* Guarantees a pure posix implementation rather than a specialized one, if
- * applicable. Intended for testing. */
-void grpc_pollset_kick_global_init_posix(void);
-
 void grpc_pollset_kick_init(grpc_pollset_kick_state *kick_state);
 void grpc_pollset_kick_destroy(grpc_pollset_kick_state *kick_state);
 
+/* Guarantees a pure posix implementation rather than a specialized one, if
+ * applicable. Intended for testing. */
+void grpc_pollset_kick_global_init_fallback_fd(void);
+
 /* Must be called before entering poll(). If return value is -1, this consumed
    an existing kick. Otherwise the return value is an FD to add to the poll set.
  */