Add Page, Runtime, Debugger agents

Summary: Runtime and Debugger agents are shipped with JSC so we reuse them. Messages are routed to them through the `LegacyDispatcher` which also handles translating their events. The Page agent emits the `Page.getResourceTree` method that the Chrome inspector expects.

Reviewed By: michalgr

Differential Revision: D4021499

fbshipit-source-id: a93d0add01cee732401f8e8db1d43205bfbd4cd4

ReactCommon/inspector/LegacyScriptDebugServer.cpp

@@ -0,0 +1,64 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#include "LegacyScriptDebugServer.h"
+
+#include <JavaScriptCore/JSGlobalObject.h>
+
+namespace facebook {
+namespace react {
+
+using namespace Inspector;
+
+LegacyScriptDebugServer::LegacyScriptDebugServer(JSC::JSGlobalObject& globalObject)
+  : Inspector::ScriptDebugServer(false)
+  , globalObject_(globalObject) {}
+
+void LegacyScriptDebugServer::addListener(ScriptDebugListener* listener)
+{
+  if (!listener) {
+    return;
+  }
+
+  bool wasEmpty = listeners_.isEmpty();
+  listeners_.add(listener);
+
+  // First listener. Attach the debugger to the JSGlobalObject.
+  if (wasEmpty) {
+    attach(&globalObject_);
+    recompileAllJSFunctions();
+  }
+}
+
+void LegacyScriptDebugServer::removeListener(ScriptDebugListener* listener, bool isBeingDestroyed) {
+  if (!listener) {
+    return;
+  }
+
+  listeners_.remove(listener);
+
+  // Last listener. Detach the debugger from the JSGlobalObject.
+  if (listeners_.isEmpty()) {
+    detach(&globalObject_, isBeingDestroyed ? Debugger::GlobalObjectIsDestructing : Debugger::TerminatingDebuggingSession);
+    if (!isBeingDestroyed) {
+      recompileAllJSFunctions();
+    }
+  }
+}
+
+void LegacyScriptDebugServer::recompileAllJSFunctions() {
+  JSC::Debugger::recompileAllJSFunctions(&globalObject_.vm());
+}
+
+void LegacyScriptDebugServer::runEventLoopWhilePaused() {
+  // Drop all locks so another thread can work in the VM while we are nested.
+  JSC::JSLock::DropAllLocks dropAllLocks(&globalObject_.vm());
+
+  // Spinning here is our best option, we could override the method
+  // notifyDoneProcessingDebuggerEvents but it's marked as final :(
+  while (!m_doneProcessingDebuggerEvents) {
+    usleep(10 * 1000);
+  }
+}
+
+}
+}