[inspector] support for nested scheduled breaks

src/inspector/v8-debugger-agent-impl.cc

 // Copyright 2015 the V8 project 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 "src/inspector/v8-debugger-agent-impl.h"
 
 #include <algorithm>
 
 #include "src/debug/debug-interface.h"
 #include "src/inspector/injected-script.h"
@@ skipping 113 matching lines @@
 V8DebuggerAgentImpl::V8DebuggerAgentImpl(
     V8InspectorSessionImpl* session, protocol::FrontendChannel* frontendChannel,
     protocol::DictionaryValue* state)
     : m_inspector(session->inspector()),
       m_debugger(m_inspector->debugger()),
       m_session(session),
       m_enabled(false),
       m_state(state),
       m_frontend(frontendChannel),
       m_isolate(m_inspector->isolate()),
-      m_breakReason(protocol::Debugger::Paused::ReasonEnum::Other),
       m_scheduledDebuggerStep(NoStep),
       m_javaScriptPauseScheduled(false),
       m_recursionLevelForStepOut(0) {
   clearBreakDetails();
 }
 
 V8DebuggerAgentImpl::~V8DebuggerAgentImpl() {}
 
 void V8DebuggerAgentImpl::enableImpl() {
   m_enabled = true;
@@ skipping 437 matching lines @@
                                               String16* scriptSource) {
   if (!enabled()) return Response::Error(kDebuggerNotEnabled);
   ScriptsMap::iterator it = m_scripts.find(scriptId);
   if (it == m_scripts.end())
     return Response::Error("No script for id: " + scriptId);
   v8::HandleScope handles(m_isolate);
   *scriptSource = it->second->source(m_isolate);
   return Response::OK();
 }
 
+void V8DebuggerAgentImpl::pushBreakDetails(
+    const String16& breakReason,
+    std::unique_ptr<protocol::DictionaryValue> breakAuxData) {
+  m_breakReason.push_back(breakReason);
+  m_breakAuxData.push_back(std::move(breakAuxData));
+}
+
+void V8DebuggerAgentImpl::popBreakDetails() {
+  if (m_breakReason.empty()) return;

[pfeldman, 2017/02/07 19:01:05]

Is it not strict enough to put DCHECK here? So we are still lying in some cases?

[kozy, 2017/02/07 22:54:36]

We cleanup break reasons on actual break and we don't enforce everyone to call
cancelPauseOnNextStatement in our v8-inspector.h API.

+  m_breakReason.pop_back();
+  m_breakAuxData.pop_back();
+}
+
+void V8DebuggerAgentImpl::clearBreakDetails() {
+  std::vector<String16> emptyBreakReason;
+  m_breakReason.swap(emptyBreakReason);
+  std::vector<std::unique_ptr<protocol::DictionaryValue>> emptyBreakAuxData;
+  m_breakAuxData.swap(emptyBreakAuxData);
+}
+
 void V8DebuggerAgentImpl::schedulePauseOnNextStatement(
     const String16& breakReason,
     std::unique_ptr<protocol::DictionaryValue> data) {
   if (!enabled() || m_scheduledDebuggerStep == StepInto ||
       m_javaScriptPauseScheduled || isPaused() ||
       !m_debugger->breakpointsActivated())
     return;
-  m_breakReason = breakReason;
-  m_breakAuxData = std::move(data);
-  m_debugger->setPauseOnNextStatement(true);
+  if (m_breakReason.empty()) m_debugger->setPauseOnNextStatement(true);
+  pushBreakDetails(breakReason, std::move(data));
 }
 
 void V8DebuggerAgentImpl::schedulePauseOnNextStatementIfSteppingInto() {
   DCHECK(enabled());
   if (m_scheduledDebuggerStep != StepInto || m_javaScriptPauseScheduled ||
       isPaused())
     return;
   clearBreakDetails();
   m_debugger->setPauseOnNextStatement(true);
 }
 
 void V8DebuggerAgentImpl::cancelPauseOnNextStatement() {
   if (m_javaScriptPauseScheduled || isPaused()) return;
-  clearBreakDetails();
-  m_debugger->setPauseOnNextStatement(false);
+  popBreakDetails();
+  if (m_breakReason.empty()) m_debugger->setPauseOnNextStatement(false);
 }
 
 Response V8DebuggerAgentImpl::pause() {
   if (!enabled()) return Response::Error(kDebuggerNotEnabled);
   if (m_javaScriptPauseScheduled || isPaused()) return Response::OK();
   clearBreakDetails();
   m_javaScriptPauseScheduled = true;
   m_scheduledDebuggerStep = NoStep;
   m_debugger->setPauseOnNextStatement(true);
   return Response::OK();
@@ skipping 437 matching lines @@
 
 void V8DebuggerAgentImpl::didPause(int contextId,
                                    v8::Local<v8::Value> exception,
                                    const std::vector<String16>& hitBreakpoints,
                                    bool isPromiseRejection, bool isUncaught,
                                    bool isOOMBreak) {
   JavaScriptCallFrames frames = m_debugger->currentCallFrames();
   m_pausedCallFrames.swap(frames);
   v8::HandleScope handles(m_isolate);
 
+  String16 breakReason = m_breakReason.empty()
+                             ? protocol::Debugger::Paused::ReasonEnum::Other
+                             : m_breakReason.back();
+  std::unique_ptr<protocol::DictionaryValue> breakAuxData =
+      m_breakAuxData.empty() ? nullptr : std::move(m_breakAuxData.back());
+  clearBreakDetails();
+  std::vector<std::unique_ptr<protocol::DictionaryValue>> emptyBreakAuxData;
   if (isOOMBreak) {
-    m_breakReason = protocol::Debugger::Paused::ReasonEnum::OOM;
-    m_breakAuxData = nullptr;
+    breakReason = protocol::Debugger::Paused::ReasonEnum::OOM;
+    breakAuxData = nullptr;
   } else if (!exception.IsEmpty()) {
     InjectedScript* injectedScript = nullptr;
     m_session->findInjectedScript(contextId, injectedScript);
     if (injectedScript) {
-      m_breakReason =
+      breakReason =
           isPromiseRejection
               ? protocol::Debugger::Paused::ReasonEnum::PromiseRejection
               : protocol::Debugger::Paused::ReasonEnum::Exception;
       std::unique_ptr<protocol::Runtime::RemoteObject> obj;
       injectedScript->wrapObject(exception, kBacktraceObjectGroup, false, false,
                                  &obj);
       if (obj) {
-        m_breakAuxData = obj->toValue();
-        m_breakAuxData->setBoolean("uncaught", isUncaught);
+        breakAuxData = obj->toValue();
+        breakAuxData->setBoolean("uncaught", isUncaught);
       } else {
-        m_breakAuxData = nullptr;
+        breakAuxData = nullptr;
       }
-      // m_breakAuxData might be null after this.
+      // breakAuxData might be null after this.
     }
   }
 
   std::unique_ptr<Array<String16>> hitBreakpointIds = Array<String16>::create();
 
   for (const auto& point : hitBreakpoints) {
     DebugServerBreakpointToBreakpointIdAndSourceMap::iterator
         breakpointIterator = m_serverBreakpoints.find(point);
     if (breakpointIterator != m_serverBreakpoints.end()) {
       const String16& localId = breakpointIterator->second.first;
       hitBreakpointIds->addItem(localId);
 
       BreakpointSource source = breakpointIterator->second.second;
-      if (m_breakReason == protocol::Debugger::Paused::ReasonEnum::Other &&
+      if (breakReason == protocol::Debugger::Paused::ReasonEnum::Other &&
           source == DebugCommandBreakpointSource)
-        m_breakReason = protocol::Debugger::Paused::ReasonEnum::DebugCommand;
+        breakReason = protocol::Debugger::Paused::ReasonEnum::DebugCommand;
     }
   }
 
   std::unique_ptr<Array<CallFrame>> protocolCallFrames;
   Response response = currentCallFrames(&protocolCallFrames);
   if (!response.isSuccess()) protocolCallFrames = Array<CallFrame>::create();
-  m_frontend.paused(std::move(protocolCallFrames), m_breakReason,
-                    std::move(m_breakAuxData), std::move(hitBreakpointIds),
+  m_frontend.paused(std::move(protocolCallFrames), breakReason,
+                    std::move(breakAuxData), std::move(hitBreakpointIds),
                     currentAsyncStackTrace());
   m_scheduledDebuggerStep = NoStep;
   m_javaScriptPauseScheduled = false;
 
   if (!m_continueToLocationBreakpointId.isEmpty()) {
     m_debugger->removeBreakpoint(m_continueToLocationBreakpointId);
     m_continueToLocationBreakpointId = "";
   }
 }
 
 void V8DebuggerAgentImpl::didContinue() {
   JavaScriptCallFrames emptyCallFrames;
   m_pausedCallFrames.swap(emptyCallFrames);
   clearBreakDetails();
   m_frontend.resumed();
 }
 
 void V8DebuggerAgentImpl::breakProgram(
     const String16& breakReason,
     std::unique_ptr<protocol::DictionaryValue> data) {
   if (!enabled() || !m_debugger->canBreakProgram() || m_skipAllPauses) return;
-  m_breakReason = breakReason;
-  m_breakAuxData = std::move(data);
+  pushBreakDetails(breakReason, std::move(data));
   m_scheduledDebuggerStep = NoStep;
   m_debugger->breakProgram();
 }
 
 void V8DebuggerAgentImpl::breakProgramOnException(
     const String16& breakReason,
     std::unique_ptr<protocol::DictionaryValue> data) {
   if (!enabled() ||
       m_debugger->getPauseOnExceptionsState() == v8::debug::NoBreakOnException)
     return;
   breakProgram(breakReason, std::move(data));
 }
 
-void V8DebuggerAgentImpl::clearBreakDetails() {
-  m_breakReason = protocol::Debugger::Paused::ReasonEnum::Other;
-  m_breakAuxData = nullptr;
-}
-
 void V8DebuggerAgentImpl::setBreakpointAt(const String16& scriptId,
                                           int lineNumber, int columnNumber,
                                           BreakpointSource source,
                                           const String16& condition) {
   ScriptBreakpoint breakpoint(scriptId, lineNumber, columnNumber, condition);
   String16 breakpointId = generateBreakpointId(breakpoint, source);
   resolveBreakpoint(breakpointId, breakpoint, source);
 }
 
 void V8DebuggerAgentImpl::removeBreakpointAt(const String16& scriptId,
                                              int lineNumber, int columnNumber,
                                              BreakpointSource source) {
   removeBreakpointImpl(generateBreakpointId(
       ScriptBreakpoint(scriptId, lineNumber, columnNumber, String16()),
       source));
 }
 
 void V8DebuggerAgentImpl::reset() {
   if (!enabled()) return;
   m_scheduledDebuggerStep = NoStep;
   m_blackboxedPositions.clear();
   resetBlackboxedStateCache();
   m_scripts.clear();
   m_breakpointIdToDebuggerBreakpointIds.clear();
 }
 
 }  // namespace v8_inspector