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/*
This file is part of Konsole, an X terminal.
Copyright 1997,1998 by Lars Doelle <lars.doelle@on-line.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
*/
// Own
#include "HistoryFile.h"
#include <QApplication>
#include <QStandardPaths>
// System
#include <cerrno>
#include <unistd.h>
// Qt
#include <QDir>
#include <QUrl>
#include <QDebug>
using namespace Konsole;
Q_GLOBAL_STATIC(QString, historyFileLocation)
// History File ///////////////////////////////////////////
HistoryFile::HistoryFile() :
_length(0),
_fileMap(nullptr),
_readWriteBalance(0)
{
// Determine the temp directory once
// This class is called 3 times for each "unlimited" scrollback.
// This has the down-side that users must restart to
// load changes.
if (!historyFileLocation.exists()) {
QString fileLocation;
// Validate file location
const QFileInfo fi(fileLocation);
if (fileLocation.isEmpty() || !fi.exists() || !fi.isDir() || !fi.isWritable()) {
qDebug()<<"Invalid scrollback folder "<<fileLocation<<"; using " << QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
// Per Qt docs, this path is never empty; not sure if that
// means it always exists.
fileLocation = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
const QFileInfo fi2(fileLocation);
if (!fi2.exists()) {
if (!QDir().mkpath(fileLocation)) {
qDebug()<<"Unable to create scrollback folder "<<fileLocation;
}
}
}
*historyFileLocation() = fileLocation;
}
const QString tmpDir = *historyFileLocation();
const QString tmpFormat = tmpDir + QLatin1Char('/') + QLatin1String("konsole-XXXXXX.history");
_tmpFile.setFileTemplate(tmpFormat);
if (_tmpFile.open()) {
#if defined(Q_OS_LINUX)
qDebug("HistoryFile: /proc/%lld/fd/%d", qApp->applicationPid(), _tmpFile.handle());
#endif
// On some systems QTemporaryFile creates unnamed file.
// Do not interfere in such cases.
if (_tmpFile.exists()) {
// Remove file entry from filesystem. Since the file
// is opened, it will still be available for reading
// and writing. This guarantees the file won't remain
// in filesystem after process termination, even when
// there was a crash.
unlink(QFile::encodeName(_tmpFile.fileName()).constData());
}
}
}
HistoryFile::~HistoryFile()
{
if (_fileMap != nullptr) {
unmap();
}
}
//TODO: Mapping the entire file in will cause problems if the history file becomes exceedingly large,
//(ie. larger than available memory). HistoryFile::map() should only map in sections of the file at a time,
//to avoid this.
void HistoryFile::map()
{
Q_ASSERT(_fileMap == nullptr);
if (_tmpFile.flush()) {
Q_ASSERT(_tmpFile.size() >= _length);
_fileMap = _tmpFile.map(0, _length);
}
//if mmap'ing fails, fall back to the read-lseek combination
if (_fileMap == nullptr) {
_readWriteBalance = 0;
//qDebug() << "mmap'ing history failed. errno = " << errno;
}
}
void HistoryFile::unmap()
{
Q_ASSERT(_fileMap != nullptr);
if (_tmpFile.unmap(_fileMap)) {
_fileMap = nullptr;
}
Q_ASSERT(_fileMap == nullptr);
}
void HistoryFile::add(const char *buffer, qint64 count)
{
if (_fileMap != nullptr) {
unmap();
}
if (_readWriteBalance < INT_MAX) {
_readWriteBalance++;
}
qint64 rc = 0;
if (!_tmpFile.seek(_length)) {
perror("HistoryFile::add.seek");
return;
}
rc = _tmpFile.write(buffer, count);
if (rc < 0) {
perror("HistoryFile::add.write");
return;
}
_length += rc;
}
void HistoryFile::get(char *buffer, qint64 size, qint64 loc)
{
if (loc < 0 || size < 0 || loc + size > _length) {
fprintf(stderr, "getHist(...,%lld,%lld): invalid args.\n", size, loc);
return;
}
//count number of get() calls vs. number of add() calls.
//If there are many more get() calls compared with add()
//calls (decided by using MAP_THRESHOLD) then mmap the log
//file to improve performance.
if (_readWriteBalance > INT_MIN) {
_readWriteBalance--;
}
if ((_fileMap == nullptr) && _readWriteBalance < MAP_THRESHOLD) {
map();
}
if (_fileMap != nullptr) {
memcpy(buffer, _fileMap + loc, size);
} else {
qint64 rc = 0;
if (!_tmpFile.seek(loc)) {
perror("HistoryFile::get.seek");
return;
}
rc = _tmpFile.read(buffer, size);
if (rc < 0) {
perror("HistoryFile::get.read");
return;
}
}
}
void HistoryFile::removeLast(qint64 loc)
{
if (loc < 0 || loc > _length) {
fprintf(stderr, "removeLast(%lld): invalid args.\n", loc);
return;
}
_length = loc;
}
qint64 HistoryFile::len() const
{
return _length;
}
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