DebugClients/Python/ThreadExtension.py

# -*- coding: utf-8 -*-

# Copyright (c) 2014 - 2016 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing an import hook patching thread modules to get debugged too.
"""

import os.path
import sys

if sys.version_info[0] == 2:
    import thread as _thread
else:
    import _thread

import threading

from DebugBase import DebugBase


class ThreadExtension(object):
    """
    Class implementing the thread support for the debugger.
    
    Provides methods for intercepting thread creation, retriving the running
    threads and their name and state.
    """
    def __init__(self):
        """
        Constructor
        """
        self.threadNumber = 1
        self._original_start_new_thread = None
        
        self.clientLock = threading.RLock()
        
        # dictionary of all threads running {id: DebugBase}
        self.threads = {}

        # the "current" thread, basically for variables view
        self.currentThread = self
        
        # special objects representing the main scripts thread and frame
        self.mainThread = self
        
        if sys.version_info[0] == 2:
            self.threadModName = 'thread'
        else:
            self.threadModName = '_thread'
        
        # reset already imported thread module to apply hooks at next import
        del sys.modules[self.threadModName]
        del sys.modules['threading']
        
        # provide a hook to perform a hard breakpoint
        # Use it like this:
        # if hasattr(sys, 'breakpoint): sys.breakpoint()
        sys.breakpoint = self.set_trace

    def attachThread(self, target=None, args=None, kwargs=None,
                     mainThread=False):
        """
        Public method to setup a thread for DebugClient to debug.
        
        If mainThread is True, then we are attaching to the already
        started mainthread of the app and the rest of the args are ignored.
        
        @param target the start function of the target thread (i.e. the
            user code)
        @param args arguments to pass to target
        @param kwargs keyword arguments to pass to target
        @param mainThread True, if we are attaching to the already
              started mainthread of the app
        @return identifier of the created thread
        """
        return
        try:
            self.lockClient()
            newThread = DebugThread(self, target, args, kwargs, mainThread)
            ident = -1
            if mainThread:
                ident = _thread.get_ident()
                self.mainThread = newThread
                if self.debugging:
                    sys.setprofile(newThread.profile)
            else:
                ident = _original_start_thread(newThread.bootstrap, ())
                if self.mainThread is not None:
                    self.tracePython = self.mainThread.tracePython
            newThread.set_ident(ident)
            self.threads[newThread.get_ident()] = newThread
        finally:
            self.unlockClient()
        return ident
    
    def threadTerminated(self, dbgThread):
        """
        Public method called when a DebugThread has exited.
        
        @param dbgThread the DebugThread that has exited
        """
        self.lockClient()
        try:
            del self.threads[dbgThread.get_ident()]
        except KeyError:
            pass
        finally:
            self.unlockClient()
    
    def lockClient(self, blocking=True):
        """
        Public method to acquire the lock for this client.
        
        @param blocking flag to indicating a blocking lock
        @type bool
        @return flag indicating successful locking
        @rtype bool
        """
        if blocking:
            self.clientLock.acquire()
        else:
            return self.clientLock.acquire(blocking)
    
    def unlockClient(self):
        """
        Public method to release the lock for this client.
        """
        try:
            self.clientLock.release()
        except AssertionError:
            pass
    
    def setCurrentThread(self, id):
        """
        Public method to set the current thread.

        @param id the id the current thread should be set to.
        """
        try:
            self.lockClient()
            if id is None or id not in self.threads:
                self.currentThread = None
            else:
                self.currentThread = self.threads[id]
        finally:
            self.unlockClient()
    
    def dumpThreadList(self):
        """
        Public method to send the list of threads.
        """
        threadList = []
        if self.threads and self.currentThread:
            # indication for the threaded debugger
            currentId = self.currentThread.get_ident()
            for t in self.threads.values():
                d = {}
                d["id"] = t.get_ident()
                d["name"] = t.get_name()
                d["broken"] = t.isBroken
                threadList.append(d)
        else:
            currentId = -1
            d = {}
            d["id"] = -1
            d["name"] = "MainThread"
            if hasattr(self, "isBroken"):
                d["broken"] = self.isBroken
            else:
                d["broken"] = False
            threadList.append(d)
        
        self.sendJsonCommand("ResponseThreadList", {
            "currentID": currentId,
            "threadList": threadList,
        })


#
# eflag: noqa = M702