Initial isolate reload support

runtime/vm/service.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 1433 matching lines @@
   if ((id < 0) || (id >= libs.Length())) {
     return Object::sentinel().raw();
   }
   Library& lib = Library::Handle();
   lib ^= libs.At(id);
   ASSERT(!lib.IsNull());
   if (num_parts == 2) {
     return lib.raw();
   }
   if (strcmp(parts[2], "scripts") == 0) {
-    // Script ids look like "libraries/35/scripts/library%2Furl.dart"
-    if (num_parts != 4) {
+    // Script ids look like "libraries/35/scripts/library%2Furl.dart/12345"
+    if (num_parts != 5) {
       return Object::sentinel().raw();
     }
     const String& id = String::Handle(String::New(parts[3]));
     ASSERT(!id.IsNull());
     // The id is the url of the script % encoded, decode it.
     const String& requested_url = String::Handle(String::DecodeIRI(id));
+
+    // Each script id is tagged with a load time.
+    int64_t timestamp;
+    if (!GetInteger64Id(parts[4], &timestamp, 16) || (timestamp < 0)) {
+      return Object::sentinel().raw();
+    }
+
     Script& script = Script::Handle();
     String& script_url = String::Handle();
     const Array& loaded_scripts = Array::Handle(lib.LoadedScripts());
     ASSERT(!loaded_scripts.IsNull());
     intptr_t i;
     for (i = 0; i < loaded_scripts.Length(); i++) {
       script ^= loaded_scripts.At(i);
       ASSERT(!script.IsNull());
       script_url ^= script.url();
-      if (script_url.Equals(requested_url)) {
+      if (script_url.Equals(requested_url) &&
+          (timestamp == script.load_timestamp())) {
         return script.raw();
       }
     }
   }
 
   // Not found.
   return Object::sentinel().raw();
 }
 
 static RawObject* LookupHeapObjectClasses(Thread* thread,
@@ skipping 885 matching lines @@
   }
   SourceReport report(report_set, compile_mode);
   report.PrintJSON(js,
                    script,
                    TokenPosition(start_pos),
                    TokenPosition(end_pos));
   return true;
 }
 
 
+static const MethodParameter* reload_sources_params[] = {
+  RUNNABLE_ISOLATE_PARAMETER,
+  NULL,
+};
+
+
+static bool ReloadSources(Thread* thread, JSONStream* js) {
+  Isolate* isolate = thread->isolate();
+  if (!isolate->compilation_allowed()) {
+    js->PrintError(kFeatureDisabled,
+        "Cannot reload source when running a precompiled program.");
+    return true;
+  }
+  if (Dart::snapshot_kind() == Snapshot::kAppWithJIT) {
+    js->PrintError(kFeatureDisabled,
+        "Cannot reload source when running an app snapshot.");
+    return true;
+  }
+  Dart_LibraryTagHandler handler = isolate->library_tag_handler();
+  if (handler == NULL) {
+    js->PrintError(kFeatureDisabled,
+                   "A library tag handler must be installed.");
+    return true;
+  }
+  if (isolate->IsReloading()) {
+    js->PrintError(kIsolateIsReloading,
+                   "This isolate is being reloaded.");
+    return true;
+  }
+  DebuggerStackTrace* stack = isolate->debugger()->StackTrace();
+  ASSERT(isolate->CanReload());
+
+  if (stack->Length() > 0) {
+    // TODO(turnidge): We need to support this case.
+    js->PrintError(kFeatureDisabled,
+                   "Source can only be reloaded when stack is empty.");
+    return true;
+  } else {
+    isolate->ReloadSources();
+  }
+
+  PrintSuccess(js);
+  return true;
+}
+
+
 static bool AddBreakpointCommon(Thread* thread,
                                 JSONStream* js,
                                 const String& script_uri) {
   if (!thread->isolate()->compilation_allowed()) {
     js->PrintError(kFeatureDisabled,
         "Cannot use breakpoints when running a precompiled program.");
     return true;
   }
   const char* line_param = js->LookupParam("line");
   intptr_t line = UIntParameter::Parse(line_param);
@@ skipping 1553 matching lines @@
   { "_getVMTimeline", GetVMTimeline,
     get_vm_timeline_params },
   { "_getVMTimelineFlags", GetVMTimelineFlags,
     get_vm_timeline_flags_params },
   { "pause", Pause,
     pause_params },
   { "removeBreakpoint", RemoveBreakpoint,
     remove_breakpoint_params },
   { "_restartVM", RestartVM,
     restart_vm_params },
+  { "_reloadSources", ReloadSources,
+    reload_sources_params },
   { "resume", Resume,
     resume_params },
   { "_requestHeapSnapshot", RequestHeapSnapshot,
     request_heap_snapshot_params },
   { "setExceptionPauseMode", SetExceptionPauseMode,
     set_exception_pause_mode_params },
   { "_setFlag", SetFlag,
     set_flags_params },
   { "setLibraryDebuggable", SetLibraryDebuggable,
     set_library_debuggable_params },
@@ skipping 16 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart