v8/include/v8-debug.h
yurys ae6ec1861e Provide accessor for object internal properties that doesn't require debugger to be active
Some of the DevTools' clients need to inspect JS objects without enabling debugger. This CL allows to inspect object's internal properties without enabling debugger and instantiating debug context.

Note that now debug context can be created lazily if v8::Debug::GetDebugContext is called when there is no debug listener. This is fragile and has already resulted in some subtle error. I'm going to fix that in a separate CL.

BUG=chromium:481845
LOG=Y

Review URL: https://codereview.chromium.org/1134193002

Cr-Commit-Position: refs/heads/master@{#28371}
2015-05-12 15:40:27 +00:00

281 lines
9.3 KiB
C++

// Copyright 2008 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_V8_DEBUG_H_
#define V8_V8_DEBUG_H_
#include "v8.h"
/**
* Debugger support for the V8 JavaScript engine.
*/
namespace v8 {
// Debug events which can occur in the V8 JavaScript engine.
enum DebugEvent {
Break = 1,
Exception = 2,
NewFunction = 3,
BeforeCompile = 4,
AfterCompile = 5,
CompileError = 6,
PromiseEvent = 7,
AsyncTaskEvent = 8,
};
class V8_EXPORT Debug {
public:
/**
* A client object passed to the v8 debugger whose ownership will be taken by
* it. v8 is always responsible for deleting the object.
*/
class ClientData {
public:
virtual ~ClientData() {}
};
/**
* A message object passed to the debug message handler.
*/
class Message {
public:
/**
* Check type of message.
*/
virtual bool IsEvent() const = 0;
virtual bool IsResponse() const = 0;
virtual DebugEvent GetEvent() const = 0;
/**
* Indicate whether this is a response to a continue command which will
* start the VM running after this is processed.
*/
virtual bool WillStartRunning() const = 0;
/**
* Access to execution state and event data. Don't store these cross
* callbacks as their content becomes invalid. These objects are from the
* debugger event that started the debug message loop.
*/
virtual Handle<Object> GetExecutionState() const = 0;
virtual Handle<Object> GetEventData() const = 0;
/**
* Get the debugger protocol JSON.
*/
virtual Handle<String> GetJSON() const = 0;
/**
* Get the context active when the debug event happened. Note this is not
* the current active context as the JavaScript part of the debugger is
* running in its own context which is entered at this point.
*/
virtual Handle<Context> GetEventContext() const = 0;
/**
* Client data passed with the corresponding request if any. This is the
* client_data data value passed into Debug::SendCommand along with the
* request that led to the message or NULL if the message is an event. The
* debugger takes ownership of the data and will delete it even if there is
* no message handler.
*/
virtual ClientData* GetClientData() const = 0;
virtual Isolate* GetIsolate() const = 0;
virtual ~Message() {}
};
/**
* An event details object passed to the debug event listener.
*/
class EventDetails {
public:
/**
* Event type.
*/
virtual DebugEvent GetEvent() const = 0;
/**
* Access to execution state and event data of the debug event. Don't store
* these cross callbacks as their content becomes invalid.
*/
virtual Handle<Object> GetExecutionState() const = 0;
virtual Handle<Object> GetEventData() const = 0;
/**
* Get the context active when the debug event happened. Note this is not
* the current active context as the JavaScript part of the debugger is
* running in its own context which is entered at this point.
*/
virtual Handle<Context> GetEventContext() const = 0;
/**
* Client data passed with the corresponding callback when it was
* registered.
*/
virtual Handle<Value> GetCallbackData() const = 0;
/**
* Client data passed to DebugBreakForCommand function. The
* debugger takes ownership of the data and will delete it even if
* there is no message handler.
*/
virtual ClientData* GetClientData() const = 0;
virtual ~EventDetails() {}
};
/**
* Debug event callback function.
*
* \param event_details object providing information about the debug event
*
* A EventCallback2 does not take possession of the event data,
* and must not rely on the data persisting after the handler returns.
*/
typedef void (*EventCallback)(const EventDetails& event_details);
/**
* Debug message callback function.
*
* \param message the debug message handler message object
*
* A MessageHandler2 does not take possession of the message data,
* and must not rely on the data persisting after the handler returns.
*/
typedef void (*MessageHandler)(const Message& message);
/**
* Callback function for the host to ensure debug messages are processed.
*/
typedef void (*DebugMessageDispatchHandler)();
static bool SetDebugEventListener(EventCallback that,
Handle<Value> data = Handle<Value>());
// Schedule a debugger break to happen when JavaScript code is run
// in the given isolate.
static void DebugBreak(Isolate* isolate);
// Remove scheduled debugger break in given isolate if it has not
// happened yet.
static void CancelDebugBreak(Isolate* isolate);
// Check if a debugger break is scheduled in the given isolate.
static bool CheckDebugBreak(Isolate* isolate);
// Message based interface. The message protocol is JSON.
static void SetMessageHandler(MessageHandler handler);
static void SendCommand(Isolate* isolate,
const uint16_t* command, int length,
ClientData* client_data = NULL);
/**
* Run a JavaScript function in the debugger.
* \param fun the function to call
* \param data passed as second argument to the function
* With this call the debugger is entered and the function specified is called
* with the execution state as the first argument. This makes it possible to
* get access to information otherwise not available during normal JavaScript
* execution e.g. details on stack frames. Receiver of the function call will
* be the debugger context global object, however this is a subject to change.
* The following example shows a JavaScript function which when passed to
* v8::Debug::Call will return the current line of JavaScript execution.
*
* \code
* function frame_source_line(exec_state) {
* return exec_state.frame(0).sourceLine();
* }
* \endcode
*/
static V8_DEPRECATE_SOON(
"Use maybe version",
Local<Value> Call(v8::Handle<v8::Function> fun,
Handle<Value> data = Handle<Value>()));
// TODO(dcarney): data arg should be a MaybeLocal
static MaybeLocal<Value> Call(Local<Context> context,
v8::Handle<v8::Function> fun,
Handle<Value> data = Handle<Value>());
/**
* Returns a mirror object for the given object.
*/
static V8_DEPRECATE_SOON("Use maybe version",
Local<Value> GetMirror(v8::Handle<v8::Value> obj));
static MaybeLocal<Value> GetMirror(Local<Context> context,
v8::Handle<v8::Value> obj);
/**
* Makes V8 process all pending debug messages.
*
* From V8 point of view all debug messages come asynchronously (e.g. from
* remote debugger) but they all must be handled synchronously: V8 cannot
* do 2 things at one time so normal script execution must be interrupted
* for a while.
*
* Generally when message arrives V8 may be in one of 3 states:
* 1. V8 is running script; V8 will automatically interrupt and process all
* pending messages;
* 2. V8 is suspended on debug breakpoint; in this state V8 is dedicated
* to reading and processing debug messages;
* 3. V8 is not running at all or has called some long-working C++ function;
* by default it means that processing of all debug messages will be deferred
* until V8 gets control again; however, embedding application may improve
* this by manually calling this method.
*
* Technically this method in many senses is equivalent to executing empty
* script:
* 1. It does nothing except for processing all pending debug messages.
* 2. It should be invoked with the same precautions and from the same context
* as V8 script would be invoked from, because:
* a. with "evaluate" command it can do whatever normal script can do,
* including all native calls;
* b. no other thread should call V8 while this method is running
* (v8::Locker may be used here).
*
* "Evaluate" debug command behavior currently is not specified in scope
* of this method.
*/
static void ProcessDebugMessages();
/**
* Debugger is running in its own context which is entered while debugger
* messages are being dispatched. This is an explicit getter for this
* debugger context. Note that the content of the debugger context is subject
* to change. The Context exists only when the debugger is active, i.e. at
* least one DebugEventListener or MessageHandler is set.
*/
static Local<Context> GetDebugContext();
/**
* Enable/disable LiveEdit functionality for the given Isolate
* (default Isolate if not provided). V8 will abort if LiveEdit is
* unexpectedly used. LiveEdit is enabled by default.
*/
static void SetLiveEditEnabled(Isolate* isolate, bool enable);
/**
* Returns array of internal properties specific to the value type. Result has
* the following format: [<name>, <value>,...,<name>, <value>]. Result array
* will be allocated in the current context.
*/
static MaybeLocal<Array> GetInternalProperties(Isolate* isolate,
Local<Value> value);
};
} // namespace v8
#undef EXPORT
#endif // V8_V8_DEBUG_H_