Added ctrl-\ command that dumps isolate stacks to dart binary.

runtime/bin/vmstats_impl.cc

Index: runtime/bin/vmstats_impl.cc
===================================================================
--- runtime/bin/vmstats_impl.cc	(revision 21583)
+++ runtime/bin/vmstats_impl.cc	(working copy)
@@ -27,13 +27,25 @@
 dart::Mutex* VmStatusService::mutex_;
 
 
-void VmStats::Start(int port, const char* root_dir) {
+void VmStats::Start(int port, const char* root_dir, bool verbose) {
   if (instance_ != NULL) {
     FATAL("VmStats already started.");
   }
-  instance_ = new VmStats();
+  instance_ = new VmStats(verbose);
   instance_monitor_ = new dart::Monitor();
+  Initialize();
   VmStatusService::InitOnce();
+
+  if (port >= 0) {
+    StartServer(port, root_dir);
+  }
+}
+
+
+void VmStats::StartServer(int port, const char* root_dir) {
+  ASSERT(port >= 0);
+  ASSERT(instance_ != NULL);
+  ASSERT(instance_monitor_ != NULL);
   Socket::Initialize();
 
   if (root_dir != NULL) {
@@ -68,7 +80,6 @@
   }
 }
 
-
 void VmStats::Stop() {
   ASSERT(instance_ != NULL);
   MonitorLocker ml(instance_monitor_);
@@ -87,18 +98,14 @@
 
 void VmStats::AddIsolate(IsolateData* isolate_data,
                          Dart_Isolate isolate) {
-  if (instance_ != NULL) {
-    MonitorLocker ml(instance_monitor_);
-    instance_->isolate_table_[isolate_data] = isolate;
-  }
+  MonitorLocker ml(instance_monitor_);
+  instance_->isolate_table_[isolate_data] = isolate;
 }
 
 
 void VmStats::RemoveIsolate(IsolateData* isolate_data) {
-  if (instance_ != NULL) {
-    MonitorLocker ml(instance_monitor_);
-    instance_->isolate_table_.erase(isolate_data);
-  }
+  MonitorLocker ml(instance_monitor_);
+  instance_->isolate_table_.erase(isolate_data);
 }
 
 
@@ -234,7 +241,9 @@
     }
     char* url = strdup(&buffer[4]);
 
-    Log::Print("vmstats: %s requested\n", url);
+    if (instance_->verbose_) {
+      Log::Print("vmstats: %s requested\n", url);
+    }
     char* content = NULL;
 
     // Check for VmStats-specific URLs.
@@ -314,10 +323,10 @@
              reinterpret_cast<intptr_t>(isolate));
     char* status = VmStatusService::GetVmStatus(request);
     if (status != NULL) {
-      text.AddString(status);
       if (!first) {
         text.AddString(",\n");
       }
+      text.AddString(status);
       first = false;
       free(status);
     }
@@ -327,6 +336,94 @@
 }
 
 
+// Advance the scanner to the value token of a specified name-value pair.
+void SeekNamedValue(const char* name, dart::JSONScanner* scanner) {
+  while (!scanner->EOM()) {
+    scanner->Scan();
+    if (scanner->IsStringLiteral(name)) {
+      scanner->Scan();
+      ASSERT(scanner->CurrentToken() == dart::JSONScanner::TokenColon);
+      scanner->Scan();
+     return;
+    }
+  }
+}
+
+
+// Windows doesn't have strndup(), so this is a simple, private version.
+static char* StrNDup(const char* s, uword len) {
+  if (strlen(s) < len) {
+    len = strlen(s);
+  }
+  char* result = reinterpret_cast<char*>(malloc(len + 1));
+  memmove(result, s, len);
+  result[len + 1] = '\0';
+  return result;
+}
+
+
+void VmStats::DumpStackThread(uword unused) {
+  Log::Print("Isolate dump:\n");
+  IsolateTable::iterator itr;
+  MonitorLocker ml(instance_monitor_);
+  for (itr = instance_->isolate_table_.begin();
+       itr != instance_->isolate_table_.end(); ++itr) {
+    Dart_Isolate isolate = itr->second;
+
+    // Print isolate name and details.
+    static char buffer[512];
+    snprintf(buffer, sizeof(buffer),
+             "/isolate/0x%"Px, reinterpret_cast<intptr_t>(isolate));
+    char* isolate_details = VmStatusService::GetVmStatus(buffer);
+    if (isolate_details != NULL) {
+      dart::JSONScanner scanner(isolate_details);
+      SeekNamedValue("name", &scanner);
+      char* name = StrNDup(scanner.TokenChars(), scanner.TokenLen());
+      SeekNamedValue("port", &scanner);
+      char* port = StrNDup(scanner.TokenChars(), scanner.TokenLen());
+      Log::Print("\"%s\" port=%s\n", name, port);
+      free(isolate_details);
+      free(port);
+      free(name);
+    }
+
+    // Print stack trace.
+    snprintf(buffer, sizeof(buffer),
+             "/isolate/0x%"Px"/stacktrace",
+             reinterpret_cast<intptr_t>(isolate));
+    char* trace = VmStatusService::GetVmStatus(buffer);
+    if (trace != NULL) {
+      dart::JSONScanner scanner(trace);
+      while (true) {
+        SeekNamedValue("url", &scanner);
+        if (scanner.CurrentToken() == dart::JSONScanner::TokenEOM) {
+          break;
+        }
+        char* url = StrNDup(scanner.TokenChars(), scanner.TokenLen());
+        SeekNamedValue("line", &scanner);
+        char* line = StrNDup(scanner.TokenChars(), scanner.TokenLen());
+        SeekNamedValue("function", &scanner);
+        char* function = StrNDup(scanner.TokenChars(), scanner.TokenLen());
+        Log::Print("  at %s(%s:%s)\n", function, url, line);
+        free(url);
+        free(line);
+        free(function);
+      }
+      free(trace);
+    }
+  }
+}
+
+
+void VmStats::DumpStack() {
+  int err = dart::Thread::Start(DumpStackThread, 0);
+  if (err != 0) {
+    Log::PrintErr("Failed starting VmStats stackdump thread: %d\n", err);
+    Shutdown();
+  }
+}
+
+
 // Global static pointer used to ensure a single instance of the class.
 VmStatusService* VmStatusService::instance_ = NULL;
 
@@ -346,6 +443,8 @@
 
 
 int VmStatusService::RegisterPlugin(Dart_VmStatusCallback callback) {
+  ASSERT(VmStatusService::instance_ != NULL);
+  ASSERT(VmStatusService::mutex_ != NULL);
   MutexLocker ml(mutex_);
   if (callback == NULL) {
     return -1;
@@ -362,6 +461,7 @@
 
 
 char* VmStatusService::GetVmStatus(const char* request) {
+  ASSERT(VmStatusService::instance_ != NULL);
   VmStatusPlugin* plugin = instance_->registered_plugin_list_;
   while (plugin != NULL) {
     char* result = (plugin->callback())(request);