Bug 1470151 - Make dumpCoverage and resetCoverage return a Promise that is resolved when the parent process and all content processes are done with dumping or resetting coverage counters. r=froydnj

--HG--
extra : rebase_source : a393fb7eddfad3be12162791c864fa7f2dad7f1b
extra : source : ddde7dd347d451798becc0615468dd9acc5e609c

dom/ipc/ContentChild.cpp

@@ -3696,10 +3696,11 @@ ContentChild::RecvShareCodeCoverageMutex(const CrossProcessMutexHandle& aHandle)
 }
 
 mozilla::ipc::IPCResult
-ContentChild::RecvDumpCodeCoverageCounters()
+ContentChild::RecvDumpCodeCoverageCounters(DumpCodeCoverageCountersResolver&& aResolver)
 {
 #ifdef MOZ_CODE_COVERAGE
-  CodeCoverageHandler::DumpCounters(0);
+  CodeCoverageHandler::DumpCounters();
+  aResolver(/* unused */ true);
   return IPC_OK();
 #else
   MOZ_CRASH("Shouldn't receive this message in non-code coverage builds!");
@@ -3707,10 +3708,11 @@ ContentChild::RecvDumpCodeCoverageCounters()
 }
 
 mozilla::ipc::IPCResult
-ContentChild::RecvResetCodeCoverageCounters()
+ContentChild::RecvResetCodeCoverageCounters(ResetCodeCoverageCountersResolver&& aResolver)
 {
 #ifdef MOZ_CODE_COVERAGE
-  CodeCoverageHandler::ResetCounters(0);
+  CodeCoverageHandler::ResetCounters();
+  aResolver(/* unused */ true);
   return IPC_OK();
 #else
   MOZ_CRASH("Shouldn't receive this message in non-code coverage builds!");

dom/ipc/ContentChild.h

@@ -624,10 +624,10 @@ public:
   RecvShareCodeCoverageMutex(const CrossProcessMutexHandle& aHandle) override;
 
   virtual mozilla::ipc::IPCResult
-  RecvDumpCodeCoverageCounters() override;
+  RecvDumpCodeCoverageCounters(DumpCodeCoverageCountersResolver&& aResolver) override;
 
   virtual mozilla::ipc::IPCResult
-  RecvResetCodeCoverageCounters() override;
+  RecvResetCodeCoverageCounters(ResetCodeCoverageCountersResolver&& aResolver) override;
 
   virtual mozilla::ipc::IPCResult
   RecvSetInputEventQueueEnabled() override;

dom/ipc/PContent.ipdl

@@ -633,8 +633,8 @@ child:
     async SetPluginList(uint32_t pluginEpoch, PluginTag[] plugins, FakePluginTag[] fakePlugins);
 
     async ShareCodeCoverageMutex(CrossProcessMutexHandle handle);
-    async DumpCodeCoverageCounters();
-    async ResetCodeCoverageCounters();
+    async DumpCodeCoverageCounters() returns (bool unused);
+    async ResetCodeCoverageCounters() returns (bool unused);
 
     /*
      * IPC message to enable the input event queue on the main thread of the

tools/code-coverage/CodeCoverageHandler.cpp

@@ -44,7 +44,7 @@ void counters_reset() {
 
 StaticAutoPtr<CodeCoverageHandler> CodeCoverageHandler::instance;
 
-void CodeCoverageHandler::DumpCounters(int)
+void CodeCoverageHandler::DumpCounters()
 {
   CrossProcessMutexAutoLock lock(*CodeCoverageHandler::Get()->GetMutex());
 
@@ -53,7 +53,12 @@ void CodeCoverageHandler::DumpCounters(int)
   printf_stderr("[CodeCoverage] Dump completed.\n");
 }
 
-void CodeCoverageHandler::ResetCounters(int)
+void CodeCoverageHandler::DumpCountersSignalHandler(int)
+{
+  DumpCounters();
+}
+
+void CodeCoverageHandler::ResetCounters()
 {
   CrossProcessMutexAutoLock lock(*CodeCoverageHandler::Get()->GetMutex());
 
@@ -62,20 +67,25 @@ void CodeCoverageHandler::ResetCounters(int)
   printf_stderr("[CodeCoverage] Reset completed.\n");
 }
 
+void CodeCoverageHandler::ResetCountersSignalHandler(int)
+{
+  ResetCounters();
+}
+
 void CodeCoverageHandler::SetSignalHandlers()
 {
 #ifndef XP_WIN
   printf_stderr("[CodeCoverage] Setting handlers for process %d.\n", getpid());
 
   struct sigaction dump_sa;
-  dump_sa.sa_handler = CodeCoverageHandler::DumpCounters;
+  dump_sa.sa_handler = CodeCoverageHandler::DumpCountersSignalHandler;
   dump_sa.sa_flags = SA_RESTART;
   sigemptyset(&dump_sa.sa_mask);
   DebugOnly<int> r1 = sigaction(SIGUSR1, &dump_sa, nullptr);
   MOZ_ASSERT(r1 == 0, "Failed to install GCOV SIGUSR1 handler");
 
   struct sigaction reset_sa;
-  reset_sa.sa_handler = CodeCoverageHandler::ResetCounters;
+  reset_sa.sa_handler = CodeCoverageHandler::ResetCountersSignalHandler;
   reset_sa.sa_flags = SA_RESTART;
   sigemptyset(&reset_sa.sa_mask);
   DebugOnly<int> r2 = sigaction(SIGUSR2, &reset_sa, nullptr);

tools/code-coverage/CodeCoverageHandler.h

@@ -18,8 +18,10 @@ public:
   static CodeCoverageHandler* Get();
   CrossProcessMutex* GetMutex();
   CrossProcessMutexHandle GetMutexHandle(int aProcId);
-  static void DumpCounters(int);
-  static void ResetCounters(int);
+  static void DumpCounters();
+  static void DumpCountersSignalHandler(int);
+  static void ResetCounters();
+  static void ResetCountersSignalHandler(int);
 
 private:
   CodeCoverageHandler();

tools/code-coverage/nsCodeCoverage.cpp

@@ -7,9 +7,11 @@
 #include "mozilla/CodeCoverageHandler.h"
 #include "mozilla/Unused.h"
 #include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/Promise.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
+using namespace mozilla::ipc;
 
 NS_IMPL_ISUPPORTS(nsCodeCoverage,
                   nsICodeCoverage)
@@ -22,28 +24,82 @@ nsCodeCoverage::~nsCodeCoverage()
 {
 }
 
-NS_IMETHODIMP nsCodeCoverage::DumpCounters()
+enum RequestType { Dump, Reset };
+
+class ProcessCount final {
+  NS_INLINE_DECL_REFCOUNTING(ProcessCount);
+
+public:
+  ProcessCount(uint32_t c) : mCount(c) {}
+  operator uint32_t() const { return mCount; }
+  ProcessCount& operator--() { mCount--; return *this; }
+
+private:
+  ~ProcessCount() {}
+  uint32_t mCount;
+};
+
+nsresult Request(JSContext* cx, Promise** aPromise, RequestType requestType)
 {
   MOZ_ASSERT(XRE_IsParentProcess());
   MOZ_ASSERT(NS_IsMainThread());
 
-  CodeCoverageHandler::DumpCounters(0);
-  for (auto* cp : ContentParent::AllProcesses(ContentParent::eLive)) {
-    Unused << cp->SendDumpCodeCoverageCounters();
+  nsIGlobalObject* global = xpc::NativeGlobal(JS::CurrentGlobalOrNull(cx));
+  if (NS_WARN_IF(!global)) {
+    return NS_ERROR_FAILURE;
   }
 
+  ErrorResult result;
+  RefPtr<Promise> promise = Promise::Create(global, result);
+  if (NS_WARN_IF(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  uint32_t processCount = 0;
+  for (auto* cp : ContentParent::AllProcesses(ContentParent::eLive)) {
+    ++processCount;
+  }
+
+  if (requestType == RequestType::Dump) {
+    CodeCoverageHandler::DumpCounters();
+  } else if (requestType == RequestType::Reset) {
+    CodeCoverageHandler::ResetCounters();
+  }
+
+  if (processCount == 0) {
+    promise->MaybeResolveWithUndefined();
+  } else {
+    RefPtr<ProcessCount> processCountHolder(new ProcessCount(processCount));
+
+    auto resolve = [processCountHolder, promise](bool unused) {
+      if (--(*processCountHolder) == 0) {
+        promise->MaybeResolveWithUndefined();
+      }
+    };
+
+    auto reject = [promise](ResponseRejectReason aReason) {
+      promise->MaybeReject(NS_ERROR_FAILURE);
+    };
+
+    for (auto* cp : ContentParent::AllProcesses(ContentParent::eLive)) {
+      if (requestType == RequestType::Dump) {
+        cp->SendDumpCodeCoverageCounters(resolve, reject);
+      } else if (requestType == RequestType::Reset) {
+        cp->SendResetCodeCoverageCounters(resolve, reject);
+      }
+    }
+  }
+
+  promise.forget(aPromise);
   return NS_OK;
 }
 
-NS_IMETHODIMP nsCodeCoverage::ResetCounters()
+NS_IMETHODIMP nsCodeCoverage::DumpCounters(JSContext *cx, Promise** aPromise)
 {
-  MOZ_ASSERT(XRE_IsParentProcess());
-  MOZ_ASSERT(NS_IsMainThread());
-
-  CodeCoverageHandler::ResetCounters(0);
-  for (auto* cp : ContentParent::AllProcesses(ContentParent::eLive)) {
-    Unused << cp->SendResetCodeCoverageCounters();
-  }
-
-  return NS_OK;
+  return Request(cx, aPromise, RequestType::Dump);
+}
+
+NS_IMETHODIMP nsCodeCoverage::ResetCounters(JSContext *cx, Promise** aPromise)
+{
+  return Request(cx, aPromise, RequestType::Reset);
 }

tools/code-coverage/nsICodeCoverage.idl

@@ -19,10 +19,12 @@ interface nsICodeCoverage : nsISupports
   /**
    * Write the coverage counters to disk.
    */
-  void dumpCounters();
+  [implicit_jscontext]
+  Promise dumpCounters();
 
   /**
    * Reset the coverage counters to 0 (as if nothing was executed).
    */
-  void resetCounters();
+  [implicit_jscontext]
+  Promise resetCounters();
 };