Enhance the PPAPI enter tracking.

ppapi/thunk/enter.cc

Index: ppapi/thunk/enter.cc
diff --git a/ppapi/thunk/enter.cc b/ppapi/thunk/enter.cc
index 7e9f70a7bc78cfb66936ab5d072437fca4a82904..42f4a0eaf82e970aed81e7f2ae9e3133520a1dcf 100644
--- a/ppapi/thunk/enter.cc
+++ b/ppapi/thunk/enter.cc
@@ -4,13 +4,89 @@
 
 #include "ppapi/thunk/enter.h"
 
-#include "base/lazy_instance.h"
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "ppapi/c/pp_errors.h"
 #include "ppapi/thunk/ppb_instance_api.h"
 #include "ppapi/thunk/resource_creation_api.h"
 
 namespace ppapi {
 namespace thunk {
 
+namespace subtle {
+
+bool CallbackIsRequired(const PP_CompletionCallback& callback) {
+  return callback.func != NULL &&
+         (callback.flags & PP_COMPLETIONCALLBACK_FLAG_OPTIONAL) == 0;
+}
+
+EnterBase::EnterBase()
+    : callback_(PP_BlockUntilComplete()),
+      retval_(PP_OK) {
+  // TODO(brettw) validate threads.
+}
+
+EnterBase::EnterBase(const PP_CompletionCallback& callback)
+    : callback_(CallbackIsRequired(callback) ? callback
+                                             : PP_BlockUntilComplete()),
+      retval_(PP_OK) {
+  // TODO(brettw) validate threads.
+}
+
+EnterBase::~EnterBase() {
+  if (callback_.func) {
+    // All async completions should have cleared the callback in SetResult().
+    DCHECK(retval_ != PP_OK_COMPLETIONPENDING && retval_ != PP_OK);
+    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+        callback_.func, callback_.user_data, retval_));
+  }
+}
+
+int32_t EnterBase::SetResult(int32_t result) {
+  if (!callback_.func || result == PP_OK_COMPLETIONPENDING) {
+    // Easy case, we don't need to issue the callback (either none is
+    // required, or the implementation will asynchronously issue it
+    // for us), just store the result.
+    callback_ = PP_BlockUntilComplete();
+    retval_ = result;
+    return retval_;
+  }
+
+  // This is a required callback, asynchronously issue it.
+  // TODO(brettw) make this work on different threads, etc.
+  MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+      callback_.func, callback_.user_data, result));
+
+  // Now that the callback will be issued in the future, we should return
+  // "pending" to the caller, and not issue the callback again.
+  callback_ = PP_BlockUntilComplete();
+  retval_ = PP_OK_COMPLETIONPENDING;
+  return retval_;
+}
+
+FunctionGroupBase* EnterBase::GetFunctions(PP_Instance instance,
+                                           ApiID id) const {
+  return PpapiGlobals::Get()->GetFunctionAPI(instance, id);
+}
+
+Resource* EnterBase::GetResource(PP_Resource resource) const {
+  return PpapiGlobals::Get()->GetResourceTracker()->GetResource(resource);
+}
+
+void EnterBase::SetStateForResourceError(PP_Resource /* pp_resource */,
+                                         Resource* /* resource_base */,
+                                         void* object,
+                                         bool /* report_error */) {
+  if (object)
+    return;  // Everything worked.
+
+  retval_ = PP_ERROR_BADRESOURCE;
+  // TODO(brettw) log the error.
+}
+
+}  // namespace subtle
+
 EnterResourceCreation::EnterResourceCreation(PP_Instance instance)
     : EnterFunctionNoLock<ResourceCreationAPI>(instance, true) {
 }