Upstream version 11.39.266.0

[platform/framework/web/crosswalk.git] / src / mojo / system / waiter.h

diff --git a/src/mojo/system/waiter.h b/src/mojo/system/waiter.h
index afbc8b4..af85e9c 100644 (file)
--- a/src/mojo/system/waiter.h
+++ b/src/mojo/system/waiter.h
@@ -5,11 +5,13 @@
 #ifndef MOJO_SYSTEM_WAITER_H_
 #define MOJO_SYSTEM_WAITER_H_
 
-#include "base/basictypes.h"
+#include <stdint.h>
+
+#include "base/macros.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
-#include "mojo/public/system/core.h"
-#include "mojo/public/system/system_export.h"
+#include "mojo/public/c/system/types.h"
+#include "mojo/system/system_impl_export.h"
 
 namespace mojo {
 namespace system {
@@ -18,7 +20,7 @@ namespace system {
 // under other locks, in particular, |Dispatcher::lock_|s, so |Waiter| methods
 // must never call out to other objects (in particular, |Dispatcher|s). This
 // class is thread-safe.
-class MOJO_SYSTEM_EXPORT Waiter {
+class MOJO_SYSTEM_IMPL_EXPORT Waiter {
  public:
   Waiter();
   ~Waiter();
@@ -27,30 +29,48 @@ class MOJO_SYSTEM_EXPORT Waiter {
   // each time it's used.
   void Init();
 
-  // Waits until a suitable |Awake()| is called.
+  // Waits until a suitable |Awake()| is called. (|context| may be null, in
+  // which case, obviously no context is ever returned.)
   // Returns:
-  //  - The |wake_result| passed to |Dispatcher::AddWaiter()| if it was woken up
-  //    by that dispatcher for the reason specified by |flags| (in the call to
-  //    |AddWaiter()|).
-  //  - |MOJO_RESULT_CANCELLED| if a handle (on which |MojoWait()| was called)
-  //    was closed; and
-  //  - |MOJO_RESULT_FAILED_PRECONDITION| if the reasons for being awoken given
-  //    by |flags| cannot (or can no longer) be satisfied (e.g., if the other
-  //    end of a pipe is closed).
-  MojoResult Wait(MojoDeadline deadline);
-
-  // Wake the waiter up with the given result (or no-op if it's been woken up
-  // already).
-  void Awake(MojoResult wait_result);
+  //   - The result given to the first call to |Awake()| (possibly before this
+  //     call to |Wait()|); in this case, |*context| is set to the value passed
+  //     to that call to |Awake()|.
+  //   - |MOJO_RESULT_DEADLINE_EXCEEDED| if the deadline was exceeded; in this
+  //     case |*context| is not modified.
+  //
+  // Usually, the context passed to |Awake()| will be the value passed to
+  // |Dispatcher::AddWaiter()|, which is usually the index to the array of
+  // handles passed to |MojoWaitMany()| (or 0 for |MojoWait()|).
+  //
+  // Typical |Awake()| results are:
+  //   - |MOJO_RESULT_OK| if one of the flags passed to
+  //     |MojoWait()|/|MojoWaitMany()| (hence |Dispatcher::AddWaiter()|) was
+  //     satisfied;
+  //   - |MOJO_RESULT_CANCELLED| if a handle (on which
+  //     |MojoWait()|/|MojoWaitMany()| was called) was closed (hence the
+  //     dispatcher closed); and
+  //   - |MOJO_RESULT_FAILED_PRECONDITION| if one of the set of flags passed to
+  //     |MojoWait()|/|MojoWaitMany()| cannot or can no longer be satisfied by
+  //     the corresponding handle (e.g., if the other end of a message or data
+  //     pipe is closed).
+  MojoResult Wait(MojoDeadline deadline, uint32_t* context);
+
+  // Wake the waiter up with the given result and context (or no-op if it's been
+  // woken up already).
+  void Awake(MojoResult result, uint32_t context);
 
  private:
   base::ConditionVariable cv_;  // Associated to |lock_|.
-  base::Lock lock_;  // Protects the following members.
+  base::Lock lock_;             // Protects the following members.
 #ifndef NDEBUG
   bool initialized_;
 #endif
   bool awoken_;
-  MojoResult wait_result_;
+  MojoResult awake_result_;
+  // This is a |uint32_t| because we really only need to store an index (for
+  // |MojoWaitMany()|). But in tests, it's convenient to use this for other
+  // purposes (e.g., to distinguish between different wake-up reasons).
+  uint32_t awake_context_;
 
   DISALLOW_COPY_AND_ASSIGN(Waiter);
 };