v8  5.5.372(node7.10.1)
V8 is Google's open source JavaScript engine
v8-debug.h
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1 // Copyright 2008 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_V8_DEBUG_H_
6 #define V8_V8_DEBUG_H_
7 
8 #include "v8.h" // NOLINT(build/include)
9 
10 /**
11  * Debugger support for the V8 JavaScript engine.
12  */
13 namespace v8 {
14 
15 // Debug events which can occur in the V8 JavaScript engine.
16 enum DebugEvent {
17  Break = 1,
18  Exception = 2,
24 };
25 
27  public:
28  /**
29  * A client object passed to the v8 debugger whose ownership will be taken by
30  * it. v8 is always responsible for deleting the object.
31  */
32  class ClientData {
33  public:
34  virtual ~ClientData() {}
35  };
36 
37 
38  /**
39  * A message object passed to the debug message handler.
40  */
41  class Message {
42  public:
43  /**
44  * Check type of message.
45  */
46  virtual bool IsEvent() const = 0;
47  virtual bool IsResponse() const = 0;
48  virtual DebugEvent GetEvent() const = 0;
49 
50  /**
51  * Indicate whether this is a response to a continue command which will
52  * start the VM running after this is processed.
53  */
54  virtual bool WillStartRunning() const = 0;
55 
56  /**
57  * Access to execution state and event data. Don't store these cross
58  * callbacks as their content becomes invalid. These objects are from the
59  * debugger event that started the debug message loop.
60  */
61  virtual Local<Object> GetExecutionState() const = 0;
62  virtual Local<Object> GetEventData() const = 0;
63 
64  /**
65  * Get the debugger protocol JSON.
66  */
67  virtual Local<String> GetJSON() const = 0;
68 
69  /**
70  * Get the context active when the debug event happened. Note this is not
71  * the current active context as the JavaScript part of the debugger is
72  * running in its own context which is entered at this point.
73  */
74  virtual Local<Context> GetEventContext() const = 0;
75 
76  /**
77  * Client data passed with the corresponding request if any. This is the
78  * client_data data value passed into Debug::SendCommand along with the
79  * request that led to the message or NULL if the message is an event. The
80  * debugger takes ownership of the data and will delete it even if there is
81  * no message handler.
82  */
83  virtual ClientData* GetClientData() const = 0;
84 
85  virtual Isolate* GetIsolate() const = 0;
86 
87  virtual ~Message() {}
88  };
89 
90 
91  /**
92  * An event details object passed to the debug event listener.
93  */
94  class EventDetails {
95  public:
96  /**
97  * Event type.
98  */
99  virtual DebugEvent GetEvent() const = 0;
100 
101  /**
102  * Access to execution state and event data of the debug event. Don't store
103  * these cross callbacks as their content becomes invalid.
104  */
105  virtual Local<Object> GetExecutionState() const = 0;
106  virtual Local<Object> GetEventData() const = 0;
107 
108  /**
109  * Get the context active when the debug event happened. Note this is not
110  * the current active context as the JavaScript part of the debugger is
111  * running in its own context which is entered at this point.
112  */
113  virtual Local<Context> GetEventContext() const = 0;
114 
115  /**
116  * Client data passed with the corresponding callback when it was
117  * registered.
118  */
119  virtual Local<Value> GetCallbackData() const = 0;
120 
121  /**
122  * Client data passed to DebugBreakForCommand function. The
123  * debugger takes ownership of the data and will delete it even if
124  * there is no message handler.
125  */
126  virtual ClientData* GetClientData() const = 0;
127 
128  virtual Isolate* GetIsolate() const = 0;
129 
130  virtual ~EventDetails() {}
131  };
132 
133  /**
134  * Debug event callback function.
135  *
136  * \param event_details object providing information about the debug event
137  *
138  * A EventCallback2 does not take possession of the event data,
139  * and must not rely on the data persisting after the handler returns.
140  */
141  typedef void (*EventCallback)(const EventDetails& event_details);
142 
143  /**
144  * Debug message callback function.
145  *
146  * \param message the debug message handler message object
147  *
148  * A MessageHandler2 does not take possession of the message data,
149  * and must not rely on the data persisting after the handler returns.
150  */
151  typedef void (*MessageHandler)(const Message& message);
152 
153  /**
154  * Callback function for the host to ensure debug messages are processed.
155  */
156  typedef void (*DebugMessageDispatchHandler)();
157 
158  static bool SetDebugEventListener(Isolate* isolate, EventCallback that,
159  Local<Value> data = Local<Value>());
160 
161  // Schedule a debugger break to happen when JavaScript code is run
162  // in the given isolate.
163  static void DebugBreak(Isolate* isolate);
164 
165  // Remove scheduled debugger break in given isolate if it has not
166  // happened yet.
167  static void CancelDebugBreak(Isolate* isolate);
168 
169  // Check if a debugger break is scheduled in the given isolate.
170  static bool CheckDebugBreak(Isolate* isolate);
171 
172  // Message based interface. The message protocol is JSON.
173  static void SetMessageHandler(Isolate* isolate, MessageHandler handler);
174 
175  static void SendCommand(Isolate* isolate,
176  const uint16_t* command, int length,
177  ClientData* client_data = NULL);
178 
179  /**
180  * Run a JavaScript function in the debugger.
181  * \param fun the function to call
182  * \param data passed as second argument to the function
183  * With this call the debugger is entered and the function specified is called
184  * with the execution state as the first argument. This makes it possible to
185  * get access to information otherwise not available during normal JavaScript
186  * execution e.g. details on stack frames. Receiver of the function call will
187  * be the debugger context global object, however this is a subject to change.
188  * The following example shows a JavaScript function which when passed to
189  * v8::Debug::Call will return the current line of JavaScript execution.
190  *
191  * \code
192  * function frame_source_line(exec_state) {
193  * return exec_state.frame(0).sourceLine();
194  * }
195  * \endcode
196  */
197  // TODO(dcarney): data arg should be a MaybeLocal
198  static MaybeLocal<Value> Call(Local<Context> context,
199  v8::Local<v8::Function> fun,
200  Local<Value> data = Local<Value>());
201 
202  /**
203  * Returns a mirror object for the given object.
204  */
205  static MaybeLocal<Value> GetMirror(Local<Context> context,
206  v8::Local<v8::Value> obj);
207 
208  /**
209  * Makes V8 process all pending debug messages.
210  *
211  * From V8 point of view all debug messages come asynchronously (e.g. from
212  * remote debugger) but they all must be handled synchronously: V8 cannot
213  * do 2 things at one time so normal script execution must be interrupted
214  * for a while.
215  *
216  * Generally when message arrives V8 may be in one of 3 states:
217  * 1. V8 is running script; V8 will automatically interrupt and process all
218  * pending messages;
219  * 2. V8 is suspended on debug breakpoint; in this state V8 is dedicated
220  * to reading and processing debug messages;
221  * 3. V8 is not running at all or has called some long-working C++ function;
222  * by default it means that processing of all debug messages will be deferred
223  * until V8 gets control again; however, embedding application may improve
224  * this by manually calling this method.
225  *
226  * Technically this method in many senses is equivalent to executing empty
227  * script:
228  * 1. It does nothing except for processing all pending debug messages.
229  * 2. It should be invoked with the same precautions and from the same context
230  * as V8 script would be invoked from, because:
231  * a. with "evaluate" command it can do whatever normal script can do,
232  * including all native calls;
233  * b. no other thread should call V8 while this method is running
234  * (v8::Locker may be used here).
235  *
236  * "Evaluate" debug command behavior currently is not specified in scope
237  * of this method.
238  */
239  static void ProcessDebugMessages(Isolate* isolate);
240 
241  /**
242  * Debugger is running in its own context which is entered while debugger
243  * messages are being dispatched. This is an explicit getter for this
244  * debugger context. Note that the content of the debugger context is subject
245  * to change. The Context exists only when the debugger is active, i.e. at
246  * least one DebugEventListener or MessageHandler is set.
247  */
248  static Local<Context> GetDebugContext(Isolate* isolate);
249 
250  /**
251  * While in the debug context, this method returns the top-most non-debug
252  * context, if it exists.
253  */
254  static MaybeLocal<Context> GetDebuggedContext(Isolate* isolate);
255 
256  /**
257  * Enable/disable LiveEdit functionality for the given Isolate
258  * (default Isolate if not provided). V8 will abort if LiveEdit is
259  * unexpectedly used. LiveEdit is enabled by default.
260  */
261  static void SetLiveEditEnabled(Isolate* isolate, bool enable);
262 
263  /**
264  * Returns array of internal properties specific to the value type. Result has
265  * the following format: [<name>, <value>,...,<name>, <value>]. Result array
266  * will be allocated in the current context.
267  */
268  static MaybeLocal<Array> GetInternalProperties(Isolate* isolate,
269  Local<Value> value);
270 
271  /**
272  * Defines if the ES2015 tail call elimination feature is enabled or not.
273  * The change of this flag triggers deoptimization of all functions that
274  * contain calls at tail position.
275  */
276  static bool IsTailCallEliminationEnabled(Isolate* isolate);
277  static void SetTailCallEliminationEnabled(Isolate* isolate, bool enabled);
278 };
279 
280 
281 } // namespace v8
282 
283 
284 #undef EXPORT
285 
286 
287 #endif // V8_V8_DEBUG_H_
virtual Local< Value > GetCallbackData() const =0
virtual DebugEvent GetEvent() const =0
virtual Local< Context > GetEventContext() const =0
virtual bool WillStartRunning() const =0
virtual Local< Object > GetEventData() const =0
virtual ~Message()
Definition: v8-debug.h:87
static MaybeLocal< Value > Call(Local< Context > context, v8::Local< v8::Function > fun, Local< Value > data=Local< Value >())
Definition: v8.h:1911
virtual Local< Object > GetExecutionState() const =0
static void ProcessDebugMessages(Isolate *isolate)
DebugEvent
Definition: v8-debug.h:16
static void SetTailCallEliminationEnabled(Isolate *isolate, bool enabled)
virtual DebugEvent GetEvent() const =0
virtual bool IsEvent() const =0
virtual ClientData * GetClientData() const =0
static MaybeLocal< Value > GetMirror(Local< Context > context, v8::Local< v8::Value > obj)
virtual bool IsResponse() const =0
virtual Local< Context > GetEventContext() const =0
virtual Isolate * GetIsolate() const =0
virtual ~EventDetails()
Definition: v8-debug.h:130
virtual Isolate * GetIsolate() const =0
virtual Local< String > GetJSON() const =0
static bool IsTailCallEliminationEnabled(Isolate *isolate)
void(* MessageHandler)(const Message &message)
Definition: v8-debug.h:151
static MaybeLocal< Context > GetDebuggedContext(Isolate *isolate)
Definition: libplatform.h:11
V8_INLINE Local()
Definition: v8.h:223
static bool SetDebugEventListener(Isolate *isolate, EventCallback that, Local< Value > data=Local< Value >())
static void DebugBreak(Isolate *isolate)
static bool CheckDebugBreak(Isolate *isolate)
static void SetMessageHandler(Isolate *isolate, MessageHandler handler)
Definition: v8.h:3336
static MaybeLocal< Array > GetInternalProperties(Isolate *isolate, Local< Value > value)
static void CancelDebugBreak(Isolate *isolate)
static Local< Context > GetDebugContext(Isolate *isolate)
virtual ClientData * GetClientData() const =0
virtual Local< Object > GetEventData() const =0
static void SendCommand(Isolate *isolate, const uint16_t *command, int length, ClientData *client_data=NULL)
virtual ~ClientData()
Definition: v8-debug.h:34
void(* EventCallback)(const EventDetails &event_details)
Definition: v8-debug.h:141
static void SetLiveEditEnabled(Isolate *isolate, bool enable)
#define V8_EXPORT
Definition: v8.h:61
virtual Local< Object > GetExecutionState() const =0
void(* DebugMessageDispatchHandler)()
Definition: v8-debug.h:156