Added more thread control to developer shell

src/d8.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
 #include <stdlib.h>
+#include <errno.h>
 
 #include "d8.h"
 #include "d8-debug.h"
 #include "debug.h"
 #include "api.h"
 #include "natives.h"
 #include "platform.h"
 
 
 namespace v8 {
@@ skipping 127 matching lines @@
       return ThrowException(String::New("Error loading file"));
     }
     if (!ExecuteString(source, String::New(*file), false, false)) {
       return ThrowException(String::New("Error executing  file"));
     }
   }
   return Undefined();
 }
 
 
+Handle<Value> Shell::Yield(const Arguments& args) {
+  v8::Unlocker unlocker;
+  return Undefined();
+}
+
+
 Handle<Value> Shell::Quit(const Arguments& args) {
   int exit_code = args[0]->Int32Value();
   OnExit();
   exit(exit_code);
   return Undefined();
 }
 
 
 Handle<Value> Shell::Version(const Arguments& args) {
   return String::New(V8::GetVersion());
@@ skipping 287 matching lines @@
 
 void ShellThread::Run() {
   // Prepare the context for this thread.
   Locker locker;
   HandleScope scope;
   Handle<ObjectTemplate> global_template = ObjectTemplate::New();
   global_template->Set(String::New("print"),
                        FunctionTemplate::New(Shell::Print));
   global_template->Set(String::New("load"),
                        FunctionTemplate::New(Shell::Load));
+  global_template->Set(String::New("yield"),
+                       FunctionTemplate::New(Shell::Yield));
   global_template->Set(String::New("version"),
                        FunctionTemplate::New(Shell::Version));
 
   char* ptr = const_cast<char*>(files_.start());
   while ((ptr != NULL) && (*ptr != '\0')) {
     // For each newline-separated line.
     char* next_line = ReadLine(ptr);
 
     if (*ptr == '#') {
       // Skip comment lines.
@@ skipping 29 matching lines @@
 }
 
 
 int Shell::Main(int argc, char* argv[]) {
   i::FlagList::SetFlagsFromCommandLine(&argc, argv, true);
   if (i::FLAG_help) {
     return 1;
   }
   Initialize();
   bool run_shell = (argc == 1);
+
+  // Default use preemption if threads are created.
+  bool use_preemption = true;
+
+  // Default to use lowest possible thread preemption interval to test as many
+  // edgecases as possible.
+  int preemption_interval = 1;
+
   i::List<i::Thread*> threads(1);
 
   {
     // Acquire the V8 lock once initialization has finished. Since the thread
     // below may spawn new threads accessing V8 holding the V8 lock here is
     // mandatory.
     Locker locker;
     Context::Scope context_scope(evaluation_context_);
     for (int i = 1; i < argc; i++) {
       char* str = argv[i];
       if (strcmp(str, "--shell") == 0) {
         run_shell = true;
+      } else if (strcmp(str, "--preemption") == 0) {
+        use_preemption = true;
+      } else if (strcmp(str, "--no-preemption") == 0) {
+        use_preemption = false;
+      } else if (strcmp(str, "--preemption-interval") == 0) {
+        if (i + 1 < argc) {
+          char *end = NULL;
+          preemption_interval = strtol(argv[++i], &end, 10);  // NOLINT
+          if (preemption_interval <= 0 || *end != '\0' || errno == ERANGE) {
+            printf("Invalid value for --preemption-interval '%s'\n", argv[i]);
+            return 1;
+          }
+        } else {
+          printf("Missing value for --preemption-interval\n");
+          return 1;
+       }
       } else if (strcmp(str, "-f") == 0) {
         // Ignore any -f flags for compatibility with other stand-alone
         // JavaScript engines.
         continue;
       } else if (strncmp(str, "--", 2) == 0) {
         printf("Warning: unknown flag %s.\nTry --help for options\n", str);
       } else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
         // Execute argument given to -e option directly.
         v8::HandleScope handle_scope;
         v8::Handle<v8::String> file_name = v8::String::New("unnamed");
         v8::Handle<v8::String> source = v8::String::New(argv[i + 1]);
         if (!ExecuteString(source, file_name, false, true))
           return 1;
         i++;
       } else if (strcmp(str, "-p") == 0 && i + 1 < argc) {
-        // Use the lowest possible thread preemption interval to test as many
-        // edgecases as possible.
-        Locker::StartPreemption(1);
         int size = 0;
         const char *files = ReadChars(argv[++i], &size);
         if (files == NULL) return 1;
         ShellThread *thread =
             new ShellThread(threads.length(),
                             i::Vector<const char>(files, size));
         thread->Start();
         threads.Add(thread);
       } else {
         // Use all other arguments as names of files to load and run.
         HandleScope handle_scope;
         Handle<String> file_name = v8::String::New(str);
         Handle<String> source = ReadFile(str);
         if (source.IsEmpty()) {
           printf("Error reading '%s'\n", str);
           return 1;
         }
         if (!ExecuteString(source, file_name, false, true))
           return 1;
       }
     }
 
+    // Start preemption if threads have been created and preemption is enabled.
+    if (threads.length() > 0 && use_preemption) {
+      Locker::StartPreemption(preemption_interval);
+    }
+
     // Run the remote debugger if requested.
     if (i::FLAG_remote_debugger) {
       RunRemoteDebugger(i::FLAG_debugger_port);
       return 0;
     }
 
     // Start the debugger agent if requested.
     if (i::FLAG_debugger_agent) {
       v8::Debug::EnableAgent(i::FLAG_debugger_port);
     }
@@ skipping 14 matching lines @@
   return 0;
 }
 
 
 }  // namespace v8
 
 
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }