Only reload libraries when they may have been modified.

runtime/vm/isolate.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/isolate.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/text_buffer.h"
@@ skipping 828 matching lines @@
       pause_loop_monitor_(NULL),
       loading_invalidation_gen_(kInvalidGen),
       top_level_parsing_count_(0),
       field_list_mutex_(new Mutex()),
       boxed_field_list_(GrowableObjectArray::null()),
       spawn_count_monitor_(new Monitor()),
       spawn_count_(0),
       has_attempted_reload_(false),
       no_reload_scope_depth_(0),
       reload_every_n_stack_overflow_checks_(FLAG_reload_every),
-      reload_context_(NULL) {
+      reload_context_(NULL),
+      last_reload_timestamp_(OS::GetCurrentTimeMillis()) {
   NOT_IN_PRODUCT(FlagsCopyFrom(api_flags));
   // TODO(asiva): A Thread is not available here, need to figure out
   // how the vm_tag (kEmbedderTagId) can be set, these tags need to
   // move to the OSThread structure.
   set_user_tag(UserTags::kDefaultUserTag);
 }
 
 #undef REUSABLE_HANDLE_SCOPE_INIT
 #undef REUSABLE_HANDLE_INITIALIZERS
 
@@ skipping 222 matching lines @@
 }
 
 
 #ifndef PRODUCT
 void Isolate::ReportReloadError(const Error& error) {
   ASSERT(IsReloading());
   reload_context_->AbortReload(error);
 }
 
 
-void Isolate::ReloadSources(bool dont_delete_reload_context) {
+void Isolate::ReloadSources(bool force_reload,
+                            bool dont_delete_reload_context) {
   // TODO(asiva): Add verification of canonical objects.
   ASSERT(!IsReloading());
   has_attempted_reload_ = true;
   reload_context_ = new IsolateReloadContext(this);
-  reload_context_->StartReload();
+  reload_context_->StartReload(force_reload);
   // TODO(asiva): Add verification of canonical objects.
   if (dont_delete_reload_context) {
     // Unit tests use the reload context later. Caller is responsible
     // for deleting the context.
     return;
   }
   DeleteReloadContext();
 }
 
 
@@ skipping 1783 matching lines @@
 void IsolateSpawnState::DecrementSpawnCount() {
   ASSERT(spawn_count_monitor_ != NULL);
   ASSERT(spawn_count_ != NULL);
   MonitorLocker ml(spawn_count_monitor_);
   ASSERT(*spawn_count_ > 0);
   *spawn_count_ = *spawn_count_ - 1;
   ml.Notify();
 }
 
 }  // namespace dart