Mojo: Add Dispatcher::{DuplicateBufferHandle,MapBuffer} methods.

We'll need them to implement shared memory.

(Also add TODOs for a bug that I spotted.)

R=darin@chromium.org

Review URL: https://codereview.chromium.org/169463012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252827 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 119 insertions, 6 deletions

diff --git a/mojo/system/core_impl.cc b/mojo/system/core_impl.cc
index 51a5bef..859617a 100644
--- a/mojo/system/core_impl.cc
+++ b/mojo/system/core_impl.cc
@@ -162,10 +162,14 @@ MojoResult CoreImpl::CreateMessagePipe(MojoHandle* message_pipe_handle0,
   {
     base::AutoLock locker(handle_table_lock_);
 
+    // TODO(vtl): crbug.com/345911: On failure, we should close the dispatcher
+    // (outside the table lock).
     h0 = AddDispatcherNoLock(dispatcher0);
     if (h0 == MOJO_HANDLE_INVALID)
       return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
+    // TODO(vtl): crbug.com/345911: On failure, we should close both dispatchers
+    // (outside the table lock).
     h1 = AddDispatcherNoLock(dispatcher1);
     if (h1 == MOJO_HANDLE_INVALID) {
       handle_table_.erase(h0);
@@ -359,6 +363,8 @@ MojoResult CoreImpl::ReadMessage(MojoHandle message_pipe_handle,
       // TODO(vtl): What should we do if we hit the maximum handle table size
       // here? Currently, we'll just fill in those handles with
       // |MOJO_HANDLE_INVALID| (and return success anyway).
+      // TODO(vtl): crbug.com/345911: On failure, we should close the dispatcher
+      // (outside the table lock).
       handles[i] = AddDispatcherNoLock(dispatchers[i]);
       LOG_IF(ERROR, handles[i] == MOJO_HANDLE_INVALID)
           << "Failed to add dispatcher (" << dispatchers[i].get() << ")";
@@ -398,10 +404,14 @@ MojoResult CoreImpl::CreateDataPipe(const MojoCreateDataPipeOptions* options,
   {
     base::AutoLock locker(handle_table_lock_);
 
+    // TODO(vtl): crbug.com/345911: On failure, we should close the dispatcher
+    // (outside the table lock).
     producer_handle = AddDispatcherNoLock(producer_dispatcher);
     if (producer_handle == MOJO_HANDLE_INVALID)
       return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
+    // TODO(vtl): crbug.com/345911: On failure, we should close both dispatchers
+    // (outside the table lock).
     consumer_handle = AddDispatcherNoLock(consumer_dispatcher);
     if (consumer_handle == MOJO_HANDLE_INVALID) {
       handle_table_.erase(producer_handle);
@@ -499,9 +509,32 @@ MojoResult CoreImpl::DuplicateBufferHandle(
     MojoHandle buffer_handle,
     const MojoDuplicateBufferHandleOptions* options,
     MojoHandle* new_buffer_handle) {
-  // TODO(vtl)
-  NOTIMPLEMENTED();
-  return MOJO_RESULT_UNIMPLEMENTED;
+  scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle));
+  if (!dispatcher.get())
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  if (!VerifyUserPointer<MojoHandle>(new_buffer_handle, 1))
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  scoped_refptr<Dispatcher> new_dispatcher;
+  MojoResult result = dispatcher->DuplicateBufferHandle(options,
+                                                        &new_dispatcher);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  MojoHandle new_handle;
+  {
+    base::AutoLock locker(handle_table_lock_);
+
+    // TODO(vtl): crbug.com/345911: On failure, we should close the dispatcher
+    // (outside the table lock).
+    new_handle = AddDispatcherNoLock(new_dispatcher);
+    if (new_handle == MOJO_HANDLE_INVALID)
+      return MOJO_RESULT_RESOURCE_EXHAUSTED;
+  }
+
+  *new_buffer_handle = new_handle;
+  return MOJO_RESULT_OK;
 }
 
 MojoResult CoreImpl::MapBuffer(MojoHandle buffer_handle,
@@ -509,9 +542,17 @@ MojoResult CoreImpl::MapBuffer(MojoHandle buffer_handle,
                                uint64_t num_bytes,
                                void** buffer,
                                MojoMapBufferFlags flags) {
-  // TODO(vtl)
-  NOTIMPLEMENTED();
-  return MOJO_RESULT_UNIMPLEMENTED;
+  scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle));
+  if (!dispatcher.get())
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  MojoResult result = dispatcher->MapBuffer(offset, num_bytes, buffer, flags);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  // TODO(vtl): Record the mapping.
+
+  return MOJO_RESULT_OK;
 }
 
 MojoResult CoreImpl::UnmapBuffer(void* buffer) {
diff --git a/mojo/system/core_impl_unittest.cc b/mojo/system/core_impl_unittest.cc
index bd4807b..93dc860 100644
--- a/mojo/system/core_impl_unittest.cc
+++ b/mojo/system/core_impl_unittest.cc
@@ -874,6 +874,8 @@ TEST_F(CoreImplTest, MessagePipeBasicLocalHandlePassing2) {
   EXPECT_EQ(MOJO_RESULT_OK, core()->Close(ch));
 }
 
+// TODO(vtl): Test |DuplicateBufferHandle()| and |MapBuffer()|.
+
 }  // namespace
 }  // namespace system
 }  // namespace mojo
diff --git a/mojo/system/dispatcher.cc b/mojo/system/dispatcher.cc
index acf42ee..ac02b83 100644
--- a/mojo/system/dispatcher.cc
+++ b/mojo/system/dispatcher.cc
@@ -125,6 +125,27 @@ MojoResult Dispatcher::EndReadData(uint32_t num_bytes_read) {
   return EndReadDataImplNoLock(num_bytes_read);
 }
 
+MojoResult Dispatcher::DuplicateBufferHandle(
+    const MojoDuplicateBufferHandleOptions* options,
+    scoped_refptr<Dispatcher>* new_dispatcher) {
+  base::AutoLock locker(lock_);
+  if (is_closed_)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  return DuplicateBufferHandleImplNoLock(options, new_dispatcher);
+}
+
+MojoResult Dispatcher::MapBuffer(uint64_t offset,
+                                 uint64_t num_bytes,
+                                 void** buffer,
+                                 MojoMapBufferFlags flags) {
+  base::AutoLock locker(lock_);
+  if (is_closed_)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  return MapBufferImplNoLock(offset, num_bytes, buffer, flags);
+}
+
 MojoResult Dispatcher::AddWaiter(Waiter* waiter,
                                  MojoWaitFlags flags,
                                  MojoResult wake_result) {
@@ -240,6 +261,25 @@ MojoResult Dispatcher::EndReadDataImplNoLock(uint32_t /*num_bytes_read*/) {
   return MOJO_RESULT_INVALID_ARGUMENT;
 }
 
+MojoResult Dispatcher::DuplicateBufferHandleImplNoLock(
+      const MojoDuplicateBufferHandleOptions* /*options*/,
+      scoped_refptr<Dispatcher>* /*new_dispatcher*/) {
+  lock_.AssertAcquired();
+  DCHECK(!is_closed_);
+  // By default, not supported. Only needed for buffer dispatchers.
+  return MOJO_RESULT_INVALID_ARGUMENT;
+}
+
+MojoResult Dispatcher::MapBufferImplNoLock(uint64_t /*offset*/,
+                                           uint64_t /*num_bytes*/,
+                                           void** /*buffer*/,
+                                           MojoMapBufferFlags /*flags*/) {
+  lock_.AssertAcquired();
+  DCHECK(!is_closed_);
+  // By default, not supported. Only needed for buffer dispatchers.
+  return MOJO_RESULT_INVALID_ARGUMENT;
+}
+
 MojoResult Dispatcher::AddWaiterImplNoLock(Waiter* /*waiter*/,
                                            MojoWaitFlags /*flags*/,
                                            MojoResult /*wake_result*/) {
diff --git a/mojo/system/dispatcher.h b/mojo/system/dispatcher.h
index a1bd728..59e536a 100644
--- a/mojo/system/dispatcher.h
+++ b/mojo/system/dispatcher.h
@@ -91,6 +91,16 @@ class MOJO_SYSTEM_IMPL_EXPORT Dispatcher :
                            uint32_t* buffer_num_bytes,
                            MojoReadDataFlags flags);
   MojoResult EndReadData(uint32_t num_bytes_read);
+  // |options| may be null. |new_dispatcher| must not be null, but
+  // |*new_dispatcher| should be null (and will contain the dispatcher for the
+  // new handle on success).
+  MojoResult DuplicateBufferHandle(
+      const MojoDuplicateBufferHandleOptions* options,
+      scoped_refptr<Dispatcher>* new_dispatcher);
+  MojoResult MapBuffer(uint64_t offset,
+                       uint64_t num_bytes,
+                       void** buffer,
+                       MojoMapBufferFlags flags);
 
   // Adds a waiter to this dispatcher. The waiter will be woken up when this
   // object changes state to satisfy |flags| with result |wake_result| (which
@@ -172,6 +182,13 @@ class MOJO_SYSTEM_IMPL_EXPORT Dispatcher :
                                              uint32_t* buffer_num_bytes,
                                              MojoReadDataFlags flags);
   virtual MojoResult EndReadDataImplNoLock(uint32_t num_bytes_read);
+  virtual MojoResult DuplicateBufferHandleImplNoLock(
+      const MojoDuplicateBufferHandleOptions* options,
+      scoped_refptr<Dispatcher>* new_dispatcher);
+  virtual MojoResult MapBufferImplNoLock(uint64_t offset,
+                                         uint64_t num_bytes,
+                                         void** buffer,
+                                         MojoMapBufferFlags flags);
   virtual MojoResult AddWaiterImplNoLock(Waiter* waiter,
                                          MojoWaitFlags flags,
                                          MojoResult wake_result);
diff --git a/mojo/system/dispatcher_unittest.cc b/mojo/system/dispatcher_unittest.cc
index e6d672b..9a7bedc 100644
--- a/mojo/system/dispatcher_unittest.cc
+++ b/mojo/system/dispatcher_unittest.cc
@@ -104,6 +104,8 @@ class ThreadSafetyStressThread : public base::SimpleThread {
     READ_DATA,
     BEGIN_READ_DATA,
     END_READ_DATA,
+    DUPLICATE_BUFFER_HANDLE,
+    MAP_BUFFER,
     ADD_WAITER,
     REMOVE_WAITER,
 
@@ -174,6 +176,17 @@ class ThreadSafetyStressThread : public base::SimpleThread {
         EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
                   dispatcher_->EndReadData(0));
         break;
+      case DUPLICATE_BUFFER_HANDLE: {
+        scoped_refptr<Dispatcher> unused;
+        EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
+                  dispatcher_->DuplicateBufferHandle(NULL, &unused));
+        break;
+      }
+      case MAP_BUFFER:
+        EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
+                  dispatcher_->MapBuffer(0u, 0u, NULL,
+                                         MOJO_MAP_BUFFER_FLAG_NONE));
+        break;
       case ADD_WAITER: {
         MojoResult r = dispatcher_->AddWaiter(&waiter_,
                                               MOJO_WAIT_FLAG_EVERYTHING, 0);