ppapi_proxy: Support loading and reading urls. Proxy URLLoader....

src/shared/ppapi_proxy/plugin_callback.cc

 // Copyright (c) 2010 The Native Client Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "native_client/src/shared/ppapi_proxy/plugin_callback.h"
+#include <string.h>
 #include "srpcgen/ppp_rpc.h"
 
 namespace ppapi_proxy {
 
 CompletionCallbackTable::CompletionCallbackTable()
     : next_id_(1) {
 }
 
 int32_t CompletionCallbackTable::AddCallback(
+    const PP_CompletionCallback& callback,
+    char* read_buffer) {
+  if (callback.func == NULL)
+    return 0;
+  int32_t callback_id = next_id_;
+  ++next_id_;
+  CallbackInfo info = { callback, read_buffer };
+  table_[callback_id] = info;
+  return callback_id;
+}
+
+int32_t CompletionCallbackTable::AddCallback(
     const PP_CompletionCallback& callback) {
-  if (callback.func == NULL)
-    return 0;
-  table_[next_id_] = callback;
-  return next_id_++;
+  return AddCallback(callback, NULL);
 }
 
 PP_CompletionCallback CompletionCallbackTable::RemoveCallback(
-    int32_t callback_id) {
+    int32_t callback_id, char** read_buffer) {
   CallbackTable::iterator it = table_.find(callback_id);
   if (table_.end() != it) {
-    PP_CompletionCallback callback = it->second;
+    CallbackInfo info = it->second;
     table_.erase(it);
-    return callback;
+    if (read_buffer != NULL)
+      *read_buffer = info.read_buffer;
+    return info.callback;
   }
+  *read_buffer = NULL;
   return PP_BlockUntilComplete();
 }
 
 }  // namespace ppapi_proxy
 
 // SRPC-abstraction wrapper around a PP_CompletionCallback.
 void CompletionCallbackRpcServer::RunCompletionCallback(
     NaClSrpcRpc* rpc,
     NaClSrpcClosure* done,
+    // inputs
     int32_t callback_id,
-    int32_t result) {
+    int32_t result,
+    // TODO(polina): use shm for read buffer
+    nacl_abi_size_t read_buffer_size, char* read_buffer) {
   NaClSrpcClosureRunner runner(done);
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
+
+  char* user_buffer;
   PP_CompletionCallback callback =
-      ppapi_proxy::CompletionCallbackTable::Get()->RemoveCallback(callback_id);
+      ppapi_proxy::CompletionCallbackTable::Get()->RemoveCallback(
+          callback_id, &user_buffer);
   if (callback.func == NULL)
     return;
+
+  if (user_buffer != NULL && read_buffer_size > 0)
+    memcpy(user_buffer, read_buffer, read_buffer_size);
   PP_RunCompletionCallback(&callback, result);
+
   rpc->result = NACL_SRPC_RESULT_OK;
 }