Remove libevent.

Fixed any exposed bugs across the stack.

Add a poll() based implementation. Heavily leverages pollset infrastructure to allow small polls to be the norm. Exposes a mechanism to plug in epoll/kqueue for platforms where we have them.

Simplify iomgr callbacks to return one bit of success or failure (instead of the multi valued result that was mostly unused previously). This will ease the burden on new implementations, and the previous system provided no real value anyway.

Removed timeouts on endpoint read/write routines. This simplifies porting burden by providing a more orthogonal interface, and the functionality can always be replicated when desired by using an alarm combined with endpoint_shutdown. I'm fairly certain we ended up with this interface because it was convenient to do from libevent.

Things that need attention still:
- adding an fd to a pollset is O(n^2) - but this is probably ok given that we'll not
use this for multipolling once platform specific implementations are added.
- we rely on the backup poller too often - especially for SSL handshakes and for client
connection establishment we should have a better mechanism ([] []
- Linux needs to use epoll for multiple fds, FreeBSD variants (including
Darwin) need to use kqueue. ([] []
- Linux needs to use eventfd for poll kicking. ([]
	Change on 2015/01/07 by ctiller <ctiller@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=83461069

1 files changed, 138 insertions, 0 deletions

diff --git a/src/core/iomgr/fd_posix.h b/src/core/iomgr/fd_posix.h
new file mode 100644
index 0000000000..232de0c3e0
--- /dev/null
+++ b/src/core/iomgr/fd_posix.h
@@ -0,0 +1,138 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_FD_POSIX_H_
+#define __GRPC_INTERNAL_IOMGR_FD_POSIX_H_
+
+#include "src/core/iomgr/iomgr.h"
+#include "src/core/iomgr/pollset.h"
+#include <grpc/support/atm.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+
+typedef struct {
+  grpc_iomgr_cb_func cb;
+  void *cb_arg;
+  int success;
+  gpr_atm state;
+} grpc_fd_state;
+
+typedef struct grpc_fd {
+  int fd;
+  /* refst format:
+       bit0:   1=active/0=orphaned
+       bit1-n: refcount
+     meaning that mostly we ref by two to avoid altering the orphaned bit,
+     and just unref by 1 when we're ready to flag the object as orphaned */
+  gpr_atm refst;
+
+  gpr_mu set_state_mu;
+  gpr_atm shutdown;
+
+  gpr_mu watcher_mu;
+  grpc_pollset **watchers;
+  size_t watcher_count;
+  size_t watcher_capacity;
+
+  grpc_fd_state readst;
+  grpc_fd_state writest;
+
+  grpc_iomgr_cb_func on_done;
+  void *on_done_user_data;
+} grpc_fd;
+
+/* Create a wrapped file descriptor.
+   Requires fd is a non-blocking file descriptor.
+   This takes ownership of closing fd. */
+grpc_fd *grpc_fd_create(int fd);
+
+/* Releases fd to be asynchronously destroyed.
+   on_done is called when the underlying file descriptor is definitely close()d.
+   If on_done is NULL, no callback will be made.
+   Requires: *fd initialized; no outstanding notify_on_read or
+   notify_on_write. */
+void grpc_fd_orphan(grpc_fd *fd, grpc_iomgr_cb_func on_done, void *user_data);
+
+/* Begin polling on an fd.
+   Registers that the given pollset is interested in this fd - so that if read
+   or writability interest changes, the pollset can be kicked to pick up that
+   new interest.
+   Return value is:
+     (fd_needs_read? read_mask : 0) | (fd_needs_write? write_mask : 0)
+   i.e. a combination of read_mask and write_mask determined by the fd's current
+   interest in said events.
+   Polling strategies that do not need to alter their behavior depending on the
+   fd's current interest (such as epoll) do not need to call this function. */
+gpr_uint32 grpc_fd_begin_poll(grpc_fd *fd, grpc_pollset *pollset,
+                              gpr_uint32 read_mask, gpr_uint32 write_mask);
+/* Complete polling previously started with grpc_fd_begin_poll */
+void grpc_fd_end_poll(grpc_fd *fd, grpc_pollset *pollset);
+
+/* Return 1 if this fd is orphaned, 0 otherwise */
+int grpc_fd_is_orphaned(grpc_fd *fd);
+
+/* Cause any current callbacks to error out with GRPC_CALLBACK_CANCELLED. */
+void grpc_fd_shutdown(grpc_fd *fd);
+
+/* Register read interest, causing read_cb to be called once when fd becomes
+   readable, on deadline specified by deadline, or on shutdown triggered by
+   grpc_fd_shutdown.
+   read_cb will be called with read_cb_arg when *fd becomes readable.
+   read_cb is Called with status of GRPC_CALLBACK_SUCCESS if readable,
+   GRPC_CALLBACK_TIMED_OUT if the call timed out,
+   and CANCELLED if the call was cancelled.
+
+   Requires:This method must not be called before the read_cb for any previous
+   call runs. Edge triggered events are used whenever they are supported by the
+   underlying platform. This means that users must drain fd in read_cb before
+   calling notify_on_read again. Users are also expected to handle spurious
+   events, i.e read_cb is called while nothing can be readable from fd  */
+void grpc_fd_notify_on_read(grpc_fd *fd, grpc_iomgr_cb_func read_cb,
+                            void *read_cb_arg);
+
+/* Exactly the same semantics as above, except based on writable events.  */
+void grpc_fd_notify_on_write(grpc_fd *fd, grpc_iomgr_cb_func write_cb,
+                             void *write_cb_arg);
+
+/* Notification from the poller to an fd that it has become readable or
+   writable.
+   If allow_synchronous_callback is 1, allow running the fd callback inline
+   in this callstack, otherwise register an asynchronous callback and return */
+void grpc_fd_become_readable(grpc_fd *fd, int allow_synchronous_callback);
+void grpc_fd_become_writable(grpc_fd *fd, int allow_synchronous_callback);
+
+/* Reference counting for fds */
+void grpc_fd_ref(grpc_fd *fd);
+void grpc_fd_unref(grpc_fd *fd);
+
+#endif /* __GRPC_INTERNAL_IOMGR_FD_POSIX_H_ */