VCS/StatusMonitorThread.py

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

# Copyright (c) 2006 - 2009 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the VCS status monitor thread base class.
"""

import os

from PyQt4.QtCore import QThread, QMutex, QMutexLocker, QWaitCondition, SIGNAL

class VcsStatusMonitorThread(QThread):
    """
    Class implementing the VCS status monitor thread base class.
    
    @signal vcsStatusMonitorData(QStringList) emitted to update the VCS status
    @signal vcsStatusMonitorStatus(QString, QString) emitted to signal the status of the
        monitoring thread (ok, nok, op) and a status message
    """
    def __init__(self, interval, projectDir, vcs, parent = None):
        """
        Constructor
        
        @param interval new interval in seconds (integer)
        @param projectDir project directory to monitor (string)
        @param vcs reference to the version control object
        @param parent reference to the parent object (QObject)
        """
        QThread.__init__(self, parent)
        self.setObjectName("VcsStatusMonitorThread")
        
        self.setTerminationEnabled(True)
        
        self.projectDir = projectDir
        self.vcs = vcs
        
        self.interval = interval
        self.autoUpdate = False
        
        self.statusList = []
        self.reportedStates = {}
        self.shouldUpdate = False
        
        self.monitorMutex = QMutex()
        self.monitorCondition = QWaitCondition()
        self.__stopIt = False
    
    def run(self):
        """
        Protected method implementing the tasks action.
        """
        while not self.__stopIt:
            # perform the checking task
            self.statusList = []
            self.emit(SIGNAL("vcsStatusMonitorStatus(QString, QString)"), 
                      "wait", self.trUtf8("Waiting for lock"))
            try:
                locked = self.vcs.vcsExecutionMutex.tryLock(5000)
            except TypeError:
                locked = self.vcs.vcsExecutionMutex.tryLock()
            if locked:
                try:
                    self.emit(SIGNAL("vcsStatusMonitorStatus(QString, QString)"), 
                              "op", self.trUtf8("Checking repository status"))
                    res, statusMsg = self._performMonitor()
                finally:
                    self.vcs.vcsExecutionMutex.unlock()
                if res:
                    status = "ok"
                else:
                    status = "nok"
                self.emit(SIGNAL("vcsStatusMonitorStatus(QString, QString)"), 
                          "send", self.trUtf8("Sending data"))
                self.emit(SIGNAL("vcsStatusMonitorData(QStringList)"), 
                          self.statusList)
                self.emit(SIGNAL("vcsStatusMonitorStatus(QString, QString)"), 
                          status, statusMsg)
            else:
                self.emit(SIGNAL("vcsStatusMonitorStatus(QString, QString)"), 
                          "timeout", self.trUtf8("Timed out waiting for lock"))
            
            if self.autoUpdate and self.shouldUpdate:
                try:
                    self.vcs.vcsUpdate(self.projectDir, True)
                    continue    # check again
                except TypeError:
                    pass    # compatibility for older VCS plugins
                self.shouldUpdate = False
            
            # wait until interval has expired checking for a stop condition
            self.monitorMutex.lock()
            if not self.__stopIt:
                self.monitorCondition.wait(self.monitorMutex, self.interval * 1000)
            self.monitorMutex.unlock()
        
        self.exit()
    
    def setInterval(self, interval):
        """
        Public method to change the monitor interval.
        
        @param interval new interval in seconds (integer)
        """
        locked = self.monitorMutex.tryLock()
        self.interval = interval
        self.monitorCondition.wakeAll()
        if locked:
            self.monitorMutex.unlock()
    
    def getInterval(self):
        """
        Public method to get the monitor interval.
        
        @return interval in seconds (integer)
        """
        return self.interval
    
    def setAutoUpdate(self, auto):
        """
        Public method to enable the auto update function.
        
        @param auto status of the auto update function (boolean)
        """
        self.autoUpdate = auto
    
    def getAutoUpdate(self):
        """
        Public method to retrieve the status of the auto update function.
        
        @return status of the auto update function (boolean)
        """
        return self.autoUpdate
    
    def checkStatus(self):
        """
        Public method to wake up the status monitor thread.
        """
        locked = self.monitorMutex.tryLock()
        self.monitorCondition.wakeAll()
        if locked:
            self.monitorMutex.unlock()
    
    def stop(self):
        """
        Public method to stop the monitor thread.
        """
        locked = self.monitorMutex.tryLock()
        self.__stopIt = True
        self.monitorCondition.wakeAll()
        if locked:
            self.monitorMutex.unlock()

    def clearCachedState(self, name):
        """
        Public method to clear the cached VCS state of a file/directory.
        
        @param name name of the entry to be cleared (string)
        """
        key = name.replace(self.projectDir + os.sep, '')
        try:
            del self.reportedStates[key]
        except KeyError:
            pass

    def _performMonitor(self):
        """
        Protected method implementing the real monitoring action.
        
        This method must be overridden and populate the statusList member variable
        with a list of strings giving the status in the first column and the
        path relative to the project directory starting with the third column.
        The allowed status flags are:
        <ul>
            <li>"A" path was added but not yet comitted</li>
            <li>"M" path has local changes</li>
            <li>"R" path was deleted and then re-added</li>
            <li>"U" path needs an update</li>
            <li>"Z" path contains a conflict</li>
            <li>" " path is back at normal</li>
        </ul>
        
        @return tuple of flag indicating successful operation (boolean) and 
            a status message in case of non successful operation (QString)
        """
        raise RuntimeError('Not implemented')