Refactored the logic for entering the debugger into one abstraction EnterDebu...

src/debug.h

 // Copyright 2006-2008 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
@@ skipping 13 matching lines @@
 // 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.
 
 #ifndef V8_V8_DEBUG_H_
 #define V8_V8_DEBUG_H_
 
 #include "../include/v8-debug.h"
 #include "assembler.h"
 #include "code-stubs.h"
+#include "execution.h"
 #include "factory.h"
 #include "platform.h"
 #include "string-stream.h"
 
 
 namespace v8 { namespace internal {
 
 // Step actions. NOTE: These values are in macros.py as well.
 enum StepAction {
   StepNone = -1,  // Stepping not prepared.
@@ skipping 418 matching lines @@
  private:
   bool TwoByteEqualsAscii(Vector<uint16_t> two_byte, const char* ascii);
 
   static const int kQueueInitialSize = 4;
   LockingMessageQueue command_queue_;
   LockingMessageQueue message_queue_;
   DISALLOW_COPY_AND_ASSIGN(DebugMessageThread);
 };
 
 
-// Helper class to support saving/restoring the top break frame id.
-class SaveBreakFrame {
+// This class is used for entering the debugger. Create an instance in the stack
+// to enter the debugger. This will set the current break state, make sure the
+// debugger is loaded and switch to the debugger context. If the debugger for
+// some reason could not be entered FailedToEnter will return true.
+class EnterDebugger BASE_EMBEDDED {
  public:
-  SaveBreakFrame() : set_(!it_.done()) {
+  EnterDebugger() : set_(!it_.done()) {
+    // If there is no JavaScript frames on the stack don't switch to new break
+    // and break frame.
     if (set_) {
       // Store the previous break is and frame id.
       break_id_ = Top::break_id();
       break_frame_id_ = Top::break_frame_id();
 
       // Create the new break info.
       Top::new_break(it_.frame()->id());
     }
+
+    // Make sure that debugger is loaded and enter the debugger context.
+    load_failed_ = !Debug::Load();
+    if (!load_failed_) {
+      // NOTE the member variable save which saves the previous context before
+      // this change.
+      Top::set_context(*Debug::debug_context());
+      Top::set_security_context(*Debug::debug_context());
+    }
   }
 
-  ~SaveBreakFrame() {
+  ~EnterDebugger() {
     if (set_) {
-      // restore to the previous break state.
+      // Restore to the previous break state.
       Top::set_break(break_frame_id_, break_id_);
     }
   }
 
+  // Check whether the debugger could be entered.
+  inline bool FailedToEnter() { return load_failed_; }
+
  private:
   JavaScriptFrameIterator it_;
   const bool set_;  // Was the break actually set?
   StackFrame::Id break_frame_id_;  // Previous break frame id.
   int break_id_;  // Previous break id.
-};
-
-
-class EnterDebuggerContext BASE_EMBEDDED {
- public:
-  // Enter the debugger by storing the previous top context and setting the
-  // current top context to the debugger context.
-  EnterDebuggerContext()  {
-    // NOTE the member variable save which saves the previous context before
-    // this change.
-    Top::set_context(*Debug::debug_context());
-    Top::set_security_context(*Debug::debug_context());
-  }
-
- private:
-  SaveContext save;
+  bool load_failed_;  // Did the debugger fail to load?
+  SaveContext save_;  // Saves previous context.
 };
 
 
 // Stack allocated class for disabling break.
 class DisableBreak BASE_EMBEDDED {
  public:
   // Enter the debugger by storing the previous top context and setting the
   // current top context to the debugger context.
   explicit DisableBreak(bool disable_break)  {
     prev_disable_break_ = Debug::disable_break();
@@ skipping 46 matching lines @@
   }
  private:
   Debug::AddressId id_;
   int reg_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8_DEBUG_H_