Helpviewer/History/HistoryManager.py

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

# Copyright (c) 2009 - 2011 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the history manager.
"""

from PyQt4.QtCore import pyqtSignal, QFileInfo, QDateTime, QDate, QTime, QUrl, QTimer, \
    QFile, QIODevice, QByteArray, QDataStream, QTemporaryFile
from PyQt4.QtWebKit import QWebHistoryInterface, QWebSettings

from E5Gui import E5MessageBox

from .HistoryModel import HistoryModel
from .HistoryFilterModel import HistoryFilterModel
from .HistoryTreeModel import HistoryTreeModel

from Utilities.AutoSaver import AutoSaver
import Utilities
import Preferences

HISTORY_VERSION = 42


class HistoryEntry(object):
    """
    Class implementing a history entry.
    """
    def __init__(self, url=None, dateTime=None, title=None):
        """
        Constructor
        
        @param url URL of the history entry (string)
        @param dateTime date and time this entry was created (QDateTime)
        @param title title string for the history entry (string)
        """
        self.url = url and url or ""
        self.dateTime = dateTime and dateTime or QDateTime()
        self.title = title and title or ""
    
    def __eq__(self, other):
        """
        Special method determining equality.
        
        @param other reference to the history entry to compare against (HistoryEntry)
        @return flag indicating equality (boolean)
        """
        return other.title == self.title and \
            other.url == self.url and \
            other.dateTime == self.dateTime
    
    def __lt__(self, other):
        """
        Special method determining less relation.
        
        Note: History is sorted in reverse order by date and time
        
        @param other reference to the history entry to compare against (HistoryEntry)
        @return flag indicating less (boolean)
        """
        return self.dateTime > other.dateTime
    
    def userTitle(self):
        """
        Public method to get the title of the history entry.
        
        @return title of the entry (string)
        """
        if not self.title:
            page = QFileInfo(QUrl(self.url).path()).fileName()
            if page:
                return page
            return self.url
        return self.title


class HistoryManager(QWebHistoryInterface):
    """
    Class implementing the history manager.
    
    @signal historyCleared() emitted after the history has been cleared
    @signal historyReset() emitted after the history has been reset
    @signal entryAdded(HistoryEntry) emitted after a history entry has been added
    @signal entryRemoved(HistoryEntry) emitted after a history entry has been removed
    @signal entryUpdated(int) emitted after a history entry has been updated
    """
    historyCleared = pyqtSignal()
    historyReset = pyqtSignal()
    entryAdded = pyqtSignal(HistoryEntry)
    entryRemoved = pyqtSignal(HistoryEntry)
    entryUpdated = pyqtSignal(int)
    
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent object (QObject)
        """
        super().__init__(parent)
        
        self.__saveTimer = AutoSaver(self, self.save)
        self.__daysToExpire = Preferences.getHelp("HistoryLimit")
        self.__history = []
        self.__lastSavedUrl = ""
        
        self.__expiredTimer = QTimer(self)
        self.__expiredTimer.setSingleShot(True)
        self.__expiredTimer.timeout.connect(self.__checkForExpired)
        
        self.__frequencyTimer = QTimer(self)
        self.__frequencyTimer.setSingleShot(True)
        self.__frequencyTimer.timeout.connect(self.__refreshFrequencies)
        
        self.entryAdded.connect(self.__saveTimer.changeOccurred)
        self.entryRemoved.connect(self.__saveTimer.changeOccurred)
        
        self.__load()
        
        self.__historyModel = HistoryModel(self, self)
        self.__historyFilterModel = HistoryFilterModel(self.__historyModel, self)
        self.__historyTreeModel = HistoryTreeModel(self.__historyFilterModel, self)
        
        super().setDefaultInterface(self)
        self.__startFrequencyTimer()
    
    def close(self):
        """
        Public method to close the history manager.
        """
        # remove history items on application exit
        if self.__daysToExpire == -2:
            self.clear()
        self.__saveTimer.saveIfNeccessary()
    
    def history(self):
        """
        Public method to return the history.
        
        @return reference to the list of history entries (list of HistoryEntry)
        """
        return self.__history[:]
    
    def setHistory(self, history, loadedAndSorted=False):
        """
        Public method to set a new history.
        
        @param history reference to the list of history entries to be set
            (list of HistoryEntry)
        @param loadedAndSorted flag indicating that the list is sorted (boolean)
        """
        self.__history = history[:]
        if not loadedAndSorted:
            self.__history.sort()
        
        self.__checkForExpired()
        
        if loadedAndSorted:
            try:
                self.__lastSavedUrl = self.__history[0].url
            except IndexError:
                self.__lastSavedUrl = ""
        else:
            self.__lastSavedUrl = ""
            self.__saveTimer.changeOccurred()
        self.historyReset.emit()
    
    def historyContains(self, url):
        """
        Public method to check the history for an entry.
        
        @param url URL to check for (string)
        @return flag indicating success (boolean)
        """
        return self.__historyFilterModel.historyContains(url)
    
    def _addHistoryEntry(self, itm):
        """
        Protected method to add a history item.
        
        @param itm reference to the history item to add (HistoryEntry)
        """
        globalSettings = QWebSettings.globalSettings()
        if globalSettings.testAttribute(QWebSettings.PrivateBrowsingEnabled):
            return
        
        self.__history.insert(0, itm)
        self.entryAdded.emit(itm)
        if len(self.__history) == 1:
            self.__checkForExpired()
    
    def _removeHistoryEntry(self, itm):
        """
        Protected method to remove a history item.
        
        @param itm reference to the history item to remove (HistoryEntry)
        """
        self.__lastSavedUrl = ""
        self.__history.remove(itm)
        self.entryRemoved.emit(itm)
    
    def addHistoryEntry(self, url):
        """
        Public method to add a history entry.
        
        @param url URL to be added (string)
        """
        cleanurl = QUrl(url)
        cleanurl.setPassword("")
        if cleanurl.host() is not None:
            cleanurl.setHost(cleanurl.host().lower())
        itm = HistoryEntry(cleanurl.toString(), QDateTime.currentDateTime())
        self._addHistoryEntry(itm)
    
    def updateHistoryEntry(self, url, title):
        """
        Public method to update a history entry.
        
        @param url URL of the entry to update (string)
        @param title title of the entry to update (string)
        """
        for index in range(len(self.__history)):
            if url == self.__history[index].url:
                self.__history[index].title = title
                self.__saveTimer.changeOccurred()
                if not self.__lastSavedUrl:
                    self.__lastSavedUrl = self.__history[index].url
                self.entryUpdated.emit(index)
                break
    
    def removeHistoryEntry(self, url, title=""):
        """
        Public method to remove a history entry.
        
        @param url URL of the entry to remove (QUrl)
        @param title title of the entry to remove (string)
        """
        for index in range(len(self.__history)):
            if url == QUrl(self.__history[index].url) and \
               (not title or title == self.__history[index].title):
                self._removeHistoryEntry(self.__history[index])
                break
    
    def historyModel(self):
        """
        Public method to get a reference to the history model.
        
        @return reference to the history model (HistoryModel)
        """
        return self.__historyModel
    
    def historyFilterModel(self):
        """
        Public method to get a reference to the history filter model.
        
        @return reference to the history filter model (HistoryFilterModel)
        """
        return self.__historyFilterModel
    
    def historyTreeModel(self):
        """
        Public method to get a reference to the history tree model.
        
        @return reference to the history tree model (HistoryTreeModel)
        """
        return self.__historyTreeModel
    
    def __checkForExpired(self):
        """
        Private slot to check entries for expiration.
        """
        if self.__daysToExpire < 0 or len(self.__history) == 0:
            return
        
        now = QDateTime.currentDateTime()
        nextTimeout = 0
        
        while self.__history:
            checkForExpired = QDateTime(self.__history[-1].dateTime)
            checkForExpired.setDate(checkForExpired.date().addDays(self.__daysToExpire))
            if now.daysTo(checkForExpired) > 7:
                nextTimeout = 7 * 86400
            else:
                nextTimeout = now.secsTo(checkForExpired)
            if nextTimeout > 0:
                break
            
            itm = self.__history.pop(-1)
            self.__lastSavedUrl = ""
            self.entryRemoved.emit(itm)
        self.__saveTimer.saveIfNeccessary()
        
        if nextTimeout > 0:
            self.__expiredTimer.start(nextTimeout * 1000)
    
    def daysToExpire(self):
        """
        Public method to get the days for entry expiration.
        
        @return days for entry expiration (integer)
        """
        return self.__daysToExpire
    
    def setDaysToExpire(self, limit):
        """
        Public method to set the days for entry expiration.
        
        @param limit days for entry expiration (integer)
        """
        if self.__daysToExpire == limit:
            return
        
        self.__daysToExpire = limit
        self.__checkForExpired()
        self.__saveTimer.changeOccurred()
    
    def preferencesChanged(self):
        """
        Public method to indicate a change of preferences.
        """
        self.setDaysToExpire(Preferences.getHelp("HistoryLimit"))
    
    def clear(self):
        """
        Public slot to clear the complete history.
        """
        self.__history = []
        self.__lastSavedUrl = ""
        self.__saveTimer.changeOccurred()
        self.__saveTimer.saveIfNeccessary()
        self.historyReset.emit()
        self.historyCleared.emit()
    
    def __load(self):
        """
        Private method to load the saved history entries from disk.
        """
        historyFile = QFile(Utilities.getConfigDir() + "/browser/history")
        if not historyFile.exists():
            return
        if not historyFile.open(QIODevice.ReadOnly):
            E5MessageBox.warning(None,
                self.trUtf8("Loading History"),
                self.trUtf8("""<p>Unable to open history file <b>{0}</b>.<br/>"""
                            """Reason: {1}</p>""")\
                    .format(historyFile.fileName, historyFile.errorString()))
            return
        
        history = []
        
        # double check, that the history file is sorted as it is read
        needToSort = False
        lastInsertedItem = HistoryEntry()
        data = QByteArray(historyFile.readAll())
        stream = QDataStream(data, QIODevice.ReadOnly)
        while not stream.atEnd():
            ver = stream.readUInt32()
            if ver != HISTORY_VERSION:
                continue
            itm = HistoryEntry()
            itm.url = stream.readString().decode()
            stream >> itm.dateTime
            itm.title = stream.readString().decode()
            
            if not itm.dateTime.isValid():
                continue
            
            if itm == lastInsertedItem:
                if not lastInsertedItem.title and len(history) > 0:
                    history[0].title = itm.title
                continue
            
            if not needToSort and history and lastInsertedItem < itm:
                needToSort = True
            
            history.insert(0, itm)
            lastInsertedItem = itm
        historyFile.close()
        
        if needToSort:
            history.sort()
        
        self.setHistory(history, True)
        
        # if the history had to be sorted, rewrite the history sorted
        if needToSort:
            self.__lastSavedUrl = ""
            self.__saveTimer.changeOccurred()
    
    def save(self):
        """
        Public slot to save the history entries to disk.
        """
        historyFile = QFile(Utilities.getConfigDir() + "/browser/history")
        if not historyFile.exists():
            self.__lastSavedUrl = ""
        
        saveAll = self.__lastSavedUrl == ""
        first = len(self.__history) - 1
        if not saveAll:
            # find the first one to save
            for index in range(len(self.__history)):
                if self.__history[index].url == self.__lastSavedUrl:
                    first = index - 1
                    break
        if first == len(self.__history) - 1:
            saveAll = True
        
        if saveAll:
            # use a temporary file when saving everything
            f = QTemporaryFile()
            f.setAutoRemove(False)
            opened = f.open()
        else:
            f = historyFile
            opened = f.open(QIODevice.Append)
        
        if not opened:
            E5MessageBox.warning(None,
                self.trUtf8("Saving History"),
                self.trUtf8("""<p>Unable to open history file <b>{0}</b>.<br/>"""
                            """Reason: {1}</p>""")\
                    .format(f.fileName(), f.errorString()))
            return
        
        for index in range(first, -1, -1):
            data = QByteArray()
            stream = QDataStream(data, QIODevice.WriteOnly)
            itm = self.__history[index]
            stream.writeUInt32(HISTORY_VERSION)
            stream.writeString(itm.url.encode())
            stream << itm.dateTime
            stream.writeString(itm.title.encode())
            f.write(data)
        
        f.close()
        if saveAll:
            if historyFile.exists() and not historyFile.remove():
                E5MessageBox.warning(None,
                    self.trUtf8("Saving History"),
                    self.trUtf8("""<p>Error removing old history file <b>{0}</b>."""
                                """<br/>Reason: {1}</p>""")\
                        .format(historyFile.fileName(), historyFile.errorString()))
            if not f.copy(historyFile.fileName()):
                E5MessageBox.warning(None,
                    self.trUtf8("Saving History"),
                    self.trUtf8("""<p>Error moving new history file over old one """
                                """(<b>{0}</b>).<br/>Reason: {1}</p>""")\
                        .format(historyFile.fileName(), f.errorString()))
        
        try:
            self.__lastSavedUrl = self.__history[0].url
        except IndexError:
            self.__lastSavedUrl = ""
    
    def __refreshFrequencies(self):
        """
        Private slot to recalculate the refresh frequencies.
        """
        self.__historyFilterModel.recalculateFrequencies()
        self.__startFrequencyTimer()
    
    def __startFrequencyTimer(self):
        """
        Private method to start the timer to recalculate the frequencies.
        """
        tomorrow = QDateTime(QDate.currentDate().addDays(1), QTime(3, 0))
        self.__frequencyTimer.start(QDateTime.currentDateTime().secsTo(tomorrow) * 1000)