Chris@148: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@148: 
Chris@148: /*
Chris@148:     Sonic Visualiser
Chris@148:     An audio file viewer and annotation editor.
Chris@148:     Centre for Digital Music, Queen Mary, University of London.
Chris@148:     This file copyright 2006 Chris Cannam.
Chris@148:     
Chris@148:     This program is free software; you can redistribute it and/or
Chris@148:     modify it under the terms of the GNU General Public License as
Chris@148:     published by the Free Software Foundation; either version 2 of the
Chris@148:     License, or (at your option) any later version.  See the file
Chris@148:     COPYING included with this distribution for more information.
Chris@148: */
Chris@148: 
Chris@148: #include "MatrixFile.h"
Chris@148: #include "base/TempDirectory.h"
Chris@150: #include "system/System.h"
Chris@148: #include "base/Profiler.h"
Chris@148: #include "base/Exceptions.h"
Chris@148: 
Chris@148: #include <sys/types.h>
Chris@148: #include <sys/stat.h>
Chris@148: #include <fcntl.h>
Chris@148: #include <unistd.h>
Chris@148: 
Chris@148: #include <iostream>
Chris@148: 
Chris@148: #include <cstdio>
Chris@148: #include <cassert>
Chris@148: 
Chris@148: #include <QFileInfo>
Chris@148: #include <QDir>
Chris@148: 
Chris@154: //#define DEBUG_MATRIX_FILE 1
Chris@154: //#define DEBUG_MATRIX_FILE_READ_SET 1
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@153: #ifndef DEBUG_MATRIX_FILE
Chris@148: #define DEBUG_MATRIX_FILE 1
Chris@148: #endif
Chris@153: #endif
Chris@148: 
Chris@148: std::map<QString, int> MatrixFile::m_refcount;
Chris@148: QMutex MatrixFile::m_refcountMutex;
Chris@148: 
Chris@148: MatrixFile::ResizeableBitsetMap MatrixFile::m_columnBitsets;
Chris@148: QMutex MatrixFile::m_columnBitsetWriteMutex;
Chris@148: 
Chris@148: FileReadThread *MatrixFile::m_readThread = 0;
Chris@148: 
Chris@148: static size_t totalStorage = 0;
Chris@148: static size_t totalMemory = 0;
Chris@148: static size_t totalCount = 0;
Chris@148: 
Chris@148: MatrixFile::MatrixFile(QString fileBase, Mode mode,
Chris@148:                        size_t cellSize, bool eagerCache) :
Chris@148:     m_fd(-1),
Chris@148:     m_mode(mode),
Chris@148:     m_flags(0),
Chris@148:     m_fmode(0),
Chris@148:     m_cellSize(cellSize),
Chris@148:     m_width(0),
Chris@148:     m_height(0),
Chris@148:     m_headerSize(2 * sizeof(size_t)),
Chris@148:     m_defaultCacheWidth(1024),
Chris@148:     m_prevX(0),
Chris@148:     m_eagerCache(eagerCache),
Chris@148:     m_requestToken(-1),
Chris@148:     m_spareData(0),
Chris@148:     m_columnBitset(0)
Chris@148: {
Chris@148:     Profiler profiler("MatrixFile::MatrixFile", true);
Chris@148: 
Chris@148:     if (!m_readThread) {
Chris@148:         m_readThread = new FileReadThread;
Chris@148:         m_readThread->start();
Chris@148:     }
Chris@148: 
Chris@148:     m_cache.data = 0;
Chris@148: 
Chris@148:     QDir tempDir(TempDirectory::getInstance()->getPath());
Chris@148:     QString fileName(tempDir.filePath(QString("%1.mfc").arg(fileBase)));
Chris@148:     bool newFile = !QFileInfo(fileName).exists();
Chris@148: 
Chris@148:     if (newFile && m_mode == ReadOnly) {
Chris@148:         std::cerr << "ERROR: MatrixFile::MatrixFile: Read-only mode "
Chris@148:                   << "specified, but cache file does not exist" << std::endl;
Chris@148:         throw FileNotFound(fileName);
Chris@148:     }
Chris@148: 
Chris@148:     if (!newFile && m_mode == ReadWrite) {
Chris@148:         std::cerr << "Note: MatrixFile::MatrixFile: Read/write mode "
Chris@148:                   << "specified, but file already exists; falling back to "
Chris@148:                   << "read-only mode" << std::endl;
Chris@148:         m_mode = ReadOnly;
Chris@148:     }
Chris@148: 
Chris@148:     if (!eagerCache && m_mode == ReadOnly) {
Chris@148:         std::cerr << "WARNING: MatrixFile::MatrixFile: Eager cacheing not "
Chris@148:                   << "specified, but file is open in read-only mode -- cache "
Chris@148:                   << "will not be used" << std::endl;
Chris@148:     }
Chris@148: 
Chris@148:     m_flags = 0;
Chris@148:     m_fmode = S_IRUSR | S_IWUSR;
Chris@148: 
Chris@148:     if (m_mode == ReadWrite) {
Chris@148:         m_flags = O_RDWR | O_CREAT;
Chris@148:     } else {
Chris@148:         m_flags = O_RDONLY;
Chris@148:     }
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:     std::cerr << "MatrixFile::MatrixFile: opening " << fileName.toStdString() << "..." << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     if ((m_fd = ::open(fileName.toLocal8Bit(), m_flags, m_fmode)) < 0) {
Chris@148:         ::perror("Open failed");
Chris@148:         std::cerr << "ERROR: MatrixFile::MatrixFile: "
Chris@148:                   << "Failed to open cache file \""
Chris@148:                   << fileName.toStdString() << "\"";
Chris@148:         if (m_mode == ReadWrite) std::cerr << " for writing";
Chris@148:         std::cerr << std::endl;
Chris@148:         throw FailedToOpenFile(fileName);
Chris@148:     }
Chris@148: 
Chris@148:     if (newFile) {
Chris@148:         resize(0, 0); // write header
Chris@148:     } else {
Chris@148:         size_t header[2];
Chris@148:         if (::read(m_fd, header, 2 * sizeof(size_t)) < 0) {
Chris@148:             perror("Read failed");
Chris@148:             std::cerr << "ERROR: MatrixFile::MatrixFile: "
Chris@148:                       << "Failed to read header (fd " << m_fd << ", file \""
Chris@148:                       << fileName.toStdString() << "\")" << std::endl;
Chris@148:             throw FileReadFailed(fileName);
Chris@148:         }
Chris@148:         m_width = header[0];
Chris@148:         m_height = header[1];
Chris@148:         seekTo(0, 0);
Chris@148:     }
Chris@148: 
Chris@148:     m_fileName = fileName;
Chris@148: 
Chris@148:     m_columnBitsetWriteMutex.lock();
Chris@148: 
Chris@148:     if (m_columnBitsets.find(m_fileName) == m_columnBitsets.end()) {
Chris@148:         m_columnBitsets[m_fileName] = new ResizeableBitset;
Chris@148:     }
Chris@148:     m_columnBitset = m_columnBitsets[m_fileName];
Chris@148: 
Chris@148:     m_columnBitsetWriteMutex.unlock();
Chris@148: 
Chris@148:     QMutexLocker locker(&m_refcountMutex);
Chris@148:     ++m_refcount[fileName];
Chris@148: 
Chris@148:     std::cerr << "MatrixFile(" << this << "): fd " << m_fd << ", file " << fileName.toStdString() << ", ref " << m_refcount[fileName] << std::endl;
Chris@148: 
Chris@148: //    std::cerr << "MatrixFile::MatrixFile: Done, size is " << "(" << m_width << ", " << m_height << ")" << std::endl;
Chris@148: 
Chris@148:     ++totalCount;
Chris@148: 
Chris@148: }
Chris@148: 
Chris@148: MatrixFile::~MatrixFile()
Chris@148: {
Chris@148:     char *requestData = 0;
Chris@148: 
Chris@148:     if (m_requestToken >= 0) {
Chris@148:         FileReadThread::Request request;
Chris@148:         if (m_readThread->getRequest(m_requestToken, request)) {
Chris@148:             requestData = request.data;
Chris@148:         }
Chris@148:         m_readThread->cancel(m_requestToken);
Chris@148:     }
Chris@148: 
Chris@148:     if (requestData) free(requestData);
Chris@148:     if (m_cache.data) free(m_cache.data);
Chris@148:     if (m_spareData) free(m_spareData);
Chris@148: 
Chris@148:     if (m_fd >= 0) {
Chris@148:         if (::close(m_fd) < 0) {
Chris@148:             ::perror("MatrixFile::~MatrixFile: close failed");
Chris@148:         }
Chris@148:     }
Chris@148: 
Chris@148:     if (m_fileName != "") {
Chris@148: 
Chris@148:         QMutexLocker locker(&m_refcountMutex);
Chris@148: 
Chris@148:         if (--m_refcount[m_fileName] == 0) {
Chris@148: 
Chris@148:             if (::unlink(m_fileName.toLocal8Bit())) {
Chris@148:                 ::perror("Unlink failed");
Chris@148:                 std::cerr << "WARNING: MatrixFile::~MatrixFile: reference count reached 0, but failed to unlink file \"" << m_fileName.toStdString() << "\"" << std::endl;
Chris@148:             } else {
Chris@148:                 std::cerr << "deleted " << m_fileName.toStdString() << std::endl;
Chris@148:             }
Chris@148: 
Chris@148:             QMutexLocker locker2(&m_columnBitsetWriteMutex);
Chris@148:             m_columnBitsets.erase(m_fileName);
Chris@148:             delete m_columnBitset;
Chris@148:         }
Chris@148:     }
Chris@148:     
Chris@148:     totalStorage -= (m_headerSize + (m_width * m_height * m_cellSize));
Chris@148:     totalMemory -= (2 * m_defaultCacheWidth * m_height * m_cellSize);
Chris@148:     totalCount --;
Chris@148: 
Chris@148:     std::cerr << "MatrixFile::~MatrixFile: " << std::endl;
Chris@148:     std::cerr << "Total storage now " << totalStorage/1024 << "K, theoretical max memory "
Chris@148:               << totalMemory/1024 << "K in " << totalCount << " instances" << std::endl;
Chris@148: 
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::resize(size_t w, size_t h)
Chris@148: {
Chris@148:     Profiler profiler("MatrixFile::resize", true);
Chris@148: 
Chris@148:     assert(m_mode == ReadWrite);
Chris@148: 
Chris@148:     QMutexLocker locker(&m_fdMutex);
Chris@148:     
Chris@148:     totalStorage -= (m_headerSize + (m_width * m_height * m_cellSize));
Chris@148:     totalMemory -= (2 * m_defaultCacheWidth * m_height * m_cellSize);
Chris@148: 
Chris@148:     off_t off = m_headerSize + (w * h * m_cellSize);
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:     std::cerr << "MatrixFile::resize(" << w << ", " << h << "): resizing file" << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     if (w * h < m_width * m_height) {
Chris@148:         if (::ftruncate(m_fd, off) < 0) {
Chris@148:             ::perror("WARNING: MatrixFile::resize: ftruncate failed");
Chris@148:             throw FileOperationFailed(m_fileName, "ftruncate");
Chris@148:         }
Chris@148:     }
Chris@148: 
Chris@148:     m_width = 0;
Chris@148:     m_height = 0;
Chris@148: 
Chris@148:     if (::lseek(m_fd, 0, SEEK_SET) == (off_t)-1) {
Chris@148:         ::perror("ERROR: MatrixFile::resize: Seek to write header failed");
Chris@148:         throw FileOperationFailed(m_fileName, "lseek");
Chris@148:     }
Chris@148: 
Chris@148:     size_t header[2];
Chris@148:     header[0] = w;
Chris@148:     header[1] = h;
Chris@148:     if (::write(m_fd, header, 2 * sizeof(size_t)) != 2 * sizeof(size_t)) {
Chris@148:         ::perror("ERROR: MatrixFile::resize: Failed to write header");
Chris@148:         throw FileOperationFailed(m_fileName, "write");
Chris@148:     }
Chris@148: 
Chris@148:     if (w > 0 && m_defaultCacheWidth > w) {
Chris@148:         m_defaultCacheWidth = w;
Chris@148:     }
Chris@148: 
Chris@148:     static size_t maxCacheMB = 16;
Chris@148:     if (2 * m_defaultCacheWidth * h * m_cellSize > maxCacheMB * 1024 * 1024) { //!!!
Chris@148:         m_defaultCacheWidth = (maxCacheMB * 1024 * 1024) / (2 * h * m_cellSize);
Chris@148:         if (m_defaultCacheWidth < 16) m_defaultCacheWidth = 16;
Chris@148:     }
Chris@148: 
Chris@148:     if (m_columnBitset) {
Chris@148:         QMutexLocker locker(&m_columnBitsetWriteMutex);
Chris@148:         m_columnBitset->resize(w);
Chris@148:     }
Chris@148: 
Chris@148:     if (m_cache.data) {
Chris@148:         free(m_cache.data);
Chris@148:         m_cache.data = 0;
Chris@148:     }
Chris@148: 
Chris@148:     if (m_spareData) {
Chris@148:         free(m_spareData);
Chris@148:         m_spareData = 0;
Chris@148:     }
Chris@148:     
Chris@148:     m_width = w;
Chris@148:     m_height = h;
Chris@148: 
Chris@148:     totalStorage += (m_headerSize + (m_width * m_height * m_cellSize));
Chris@148:     totalMemory += (2 * m_defaultCacheWidth * m_height * m_cellSize);
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:     std::cerr << "MatrixFile::resize(" << w << ", " << h << "): cache width "
Chris@148:               << m_defaultCacheWidth << ", storage "
Chris@148:               << (m_headerSize + w * h * m_cellSize) << ", mem "
Chris@148:               << (2 * h * m_defaultCacheWidth * m_cellSize) << std::endl;
Chris@148: 
Chris@148:     std::cerr << "Total storage " << totalStorage/1024 << "K, theoretical max memory "
Chris@148:               << totalMemory/1024 << "K in " << totalCount << " instances" << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     seekTo(0, 0);
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::reset()
Chris@148: {
Chris@148:     Profiler profiler("MatrixFile::reset", true);
Chris@148: 
Chris@148:     assert (m_mode == ReadWrite);
Chris@148:     
Chris@148:     if (m_eagerCache) {
Chris@148:         void *emptyCol = calloc(m_height, m_cellSize);
Chris@148:         for (size_t x = 0; x < m_width; ++x) setColumnAt(x, emptyCol);
Chris@148:         free(emptyCol);
Chris@148:     }
Chris@148:     
Chris@148:     if (m_columnBitset) {
Chris@148:         QMutexLocker locker(&m_columnBitsetWriteMutex);
Chris@148:         m_columnBitset->resize(m_width);
Chris@148:     }
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::getColumnAt(size_t x, void *data)
Chris@148: {
Chris@148: //    Profiler profiler("MatrixFile::getColumnAt");
Chris@148: 
Chris@148: //    assert(haveSetColumnAt(x));
Chris@148: 
Chris@148:     if (getFromCache(x, 0, m_height, data)) return;
Chris@148: 
Chris@148: //    Profiler profiler2("MatrixFile::getColumnAt (uncached)");
Chris@148: 
Chris@148:     ssize_t r = 0;
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:     std::cerr << "MatrixFile::getColumnAt(" << x << ")"
Chris@148:               << ": reading the slow way";
Chris@148: 
Chris@148:     if (m_requestToken >= 0 &&
Chris@148:         x >= m_requestingX &&
Chris@148:         x <  m_requestingX + m_requestingWidth) {
Chris@148:         
Chris@148:         std::cerr << " (awaiting " << m_requestingX << ", " << m_requestingWidth << " from disk)";
Chris@148:     }
Chris@148: 
Chris@148:     std::cerr << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     m_fdMutex.lock();
Chris@148: 
Chris@148:     if (seekTo(x, 0)) {
Chris@148:         r = ::read(m_fd, data, m_height * m_cellSize);
Chris@148:     }
Chris@148: 
Chris@148:     m_fdMutex.unlock();
Chris@148:     
Chris@148:     if (r < 0) {
Chris@148:         ::perror("MatrixFile::getColumnAt: read failed");
Chris@148:         throw FileReadFailed(m_fileName);
Chris@148:     }
Chris@148: 
Chris@148:     return;
Chris@148: }
Chris@148: 
Chris@148: bool
Chris@148: MatrixFile::getFromCache(size_t x, size_t ystart, size_t ycount, void *data)
Chris@148: {
Chris@148:     m_cacheMutex.lock();
Chris@148: 
Chris@148:     if (!m_cache.data || x < m_cache.x || x >= m_cache.x + m_cache.width) {
Chris@148:         bool left = (m_cache.data && x < m_cache.x);
Chris@148:         m_cacheMutex.unlock();
Chris@148:         primeCache(x, left); // this doesn't take effect until a later callback
Chris@148:         m_prevX = x;
Chris@148:         return false;
Chris@148:     }
Chris@148: 
Chris@148:     memcpy(data,
Chris@148:            m_cache.data + m_cellSize * ((x - m_cache.x) * m_height + ystart),
Chris@148:            ycount * m_cellSize);
Chris@148: 
Chris@148:     m_cacheMutex.unlock();
Chris@148: 
Chris@148:     if (m_cache.x > 0 && x < m_prevX && x < m_cache.x + m_cache.width/4) {
Chris@148:         primeCache(x, true);
Chris@148:     }
Chris@148: 
Chris@148:     if (m_cache.x + m_cache.width < m_width &&
Chris@148:         x > m_prevX &&
Chris@148:         x > m_cache.x + (m_cache.width * 3) / 4) {
Chris@148:         primeCache(x, false);
Chris@148:     }
Chris@148: 
Chris@148:     m_prevX = x;
Chris@148:     return true;
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::setColumnAt(size_t x, const void *data)
Chris@148: {
Chris@148:     assert(m_mode == ReadWrite);
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:     std::cerr << "MatrixFile::setColumnAt(" << x << ")" << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     ssize_t w = 0;
Chris@148:     bool seekFailed = false;
Chris@148: 
Chris@148:     m_fdMutex.lock();
Chris@148: 
Chris@148:     if (seekTo(x, 0)) {
Chris@148:         w = ::write(m_fd, data, m_height * m_cellSize);
Chris@148:     } else {
Chris@148:         seekFailed = true;
Chris@148:     }
Chris@148: 
Chris@148:     m_fdMutex.unlock();
Chris@148: 
Chris@148:     if (!seekFailed && w != ssize_t(m_height * m_cellSize)) {
Chris@148:         ::perror("WARNING: MatrixFile::setColumnAt: write failed");
Chris@148:         throw FileOperationFailed(m_fileName, "write");
Chris@148:     } else if (seekFailed) {
Chris@148:         throw FileOperationFailed(m_fileName, "seek");
Chris@148:     } else {
Chris@148:         QMutexLocker locker(&m_columnBitsetWriteMutex);
Chris@148:         m_columnBitset->set(x);
Chris@148:     }
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::suspend()
Chris@148: {
Chris@148:     QMutexLocker locker(&m_fdMutex);
Chris@148:     QMutexLocker locker2(&m_cacheMutex);
Chris@148: 
Chris@148:     if (m_fd < 0) return; // already suspended
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:     std::cerr << "MatrixFile(" << this << ":" << m_fileName.toStdString() << ")::suspend(): fd was " << m_fd << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     if (m_requestToken >= 0) {
Chris@148:         void *data = 0;
Chris@148:         FileReadThread::Request request;
Chris@148:         if (m_readThread->getRequest(m_requestToken, request)) {
Chris@148:             data = request.data;
Chris@148:         }
Chris@148:         m_readThread->cancel(m_requestToken);
Chris@148:         if (data) free(data);
Chris@148:         m_requestToken = -1;
Chris@148:     }
Chris@148: 
Chris@148:     if (m_cache.data) {
Chris@148:         free(m_cache.data);
Chris@148:         m_cache.data = 0;
Chris@148:     }
Chris@148: 
Chris@148:     if (m_spareData) {
Chris@148:         free(m_spareData);
Chris@148:         m_spareData = 0;
Chris@148:     }
Chris@148:     
Chris@148:     if (::close(m_fd) < 0) {
Chris@148:         ::perror("WARNING: MatrixFile::suspend: close failed");
Chris@148:         throw FileOperationFailed(m_fileName, "close");
Chris@148:     }
Chris@148: 
Chris@148:     m_fd = -1;
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::resume()
Chris@148: {
Chris@148:     if (m_fd >= 0) return;
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE    
Chris@148:     std::cerr << "MatrixFile(" << this << ")::resume()" << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     if ((m_fd = ::open(m_fileName.toLocal8Bit(), m_flags, m_fmode)) < 0) {
Chris@148:         ::perror("Open failed");
Chris@148:         std::cerr << "ERROR: MatrixFile::resume: "
Chris@148:                   << "Failed to open cache file \""
Chris@148:                   << m_fileName.toStdString() << "\"";
Chris@148:         if (m_mode == ReadWrite) std::cerr << " for writing";
Chris@148:         std::cerr << std::endl;
Chris@148:         throw FailedToOpenFile(m_fileName);
Chris@148:     }
Chris@148: 
Chris@148:     std::cerr << "MatrixFile(" << this << ":" << m_fileName.toStdString() << ")::resume(): fd is " << m_fd << std::endl;
Chris@148: }
Chris@148: 
Chris@148: void
Chris@148: MatrixFile::primeCache(size_t x, bool goingLeft)
Chris@148: {
Chris@148: //    Profiler profiler("MatrixFile::primeCache");
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:     std::cerr << "MatrixFile::primeCache(" << x << ", " << goingLeft << ")" << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:     size_t rx = x;
Chris@148:     size_t rw = m_defaultCacheWidth;
Chris@148: 
Chris@148:     size_t left = rw / 3;
Chris@148:     if (goingLeft) left = (rw * 2) / 3;
Chris@148: 
Chris@148:     if (rx > left) rx -= left;
Chris@148:     else rx = 0;
Chris@148: 
Chris@148:     if (rx + rw > m_width) rw = m_width - rx;
Chris@148: 
Chris@148:     if (!m_eagerCache) {
Chris@148: 
Chris@148:         size_t ti = 0;
Chris@148: 
Chris@148:         for (ti = 0; ti < rw; ++ti) {
Chris@148:             if (!m_columnBitset->get(rx + ti)) break;
Chris@148:         }
Chris@148:         
Chris@148: #ifdef DEBUG_MATRIX_FILE
Chris@148:         if (ti < rw) {
Chris@148:             std::cerr << "eagerCache is false and there's a hole at "
Chris@148:                       << rx + ti << ", reducing rw from " << rw << " to "
Chris@148:                       << ti << std::endl;
Chris@148:         }
Chris@148: #endif
Chris@148: 
Chris@148:         rw = std::min(rw, ti);
Chris@148:         if (rw < 10 || rx + rw <= x) return;
Chris@148:     }
Chris@148: 
Chris@148:     QMutexLocker locker(&m_cacheMutex);
Chris@148: 
Chris@148:     FileReadThread::Request request;
Chris@148: 
Chris@148:     if (m_requestToken >= 0 &&
Chris@148:         m_readThread->getRequest(m_requestToken, request)) {
Chris@148: 
Chris@148:         if (x >= m_requestingX &&
Chris@148:             x <  m_requestingX + m_requestingWidth) {
Chris@148: 
Chris@148:             if (m_readThread->isReady(m_requestToken)) {
Chris@148: 
Chris@148:                 if (!request.successful) {
Chris@148:                     std::cerr << "ERROR: MatrixFile::primeCache: Last request was unsuccessful" << std::endl;
Chris@148:                     throw FileReadFailed(m_fileName);
Chris@148:                 }
Chris@148:                 
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:                 std::cerr << "last request is ready! (" << m_requestingX << ", "<< m_requestingWidth << ")"  << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:                 m_cache.x = (request.start - m_headerSize) / (m_height * m_cellSize);
Chris@148:                 m_cache.width = request.size / (m_height * m_cellSize);
Chris@148:       
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:                 std::cerr << "received last request: actual size is: " << m_cache.x << ", " << m_cache.width << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:                 if (m_cache.data) {
Chris@148:                     if (m_spareData) free(m_spareData);
Chris@148:                     m_spareData = m_cache.data;
Chris@148:                 }
Chris@148:                 m_cache.data = request.data;
Chris@148: 
Chris@148:                 m_readThread->done(m_requestToken);
Chris@148:                 m_requestToken = -1;
Chris@148:             }
Chris@148: 
Chris@148:             // already requested something covering this area; wait for it
Chris@148:             return;
Chris@148:         }
Chris@148: 
Chris@148:         // the current request is no longer of any use
Chris@148:         m_readThread->cancel(m_requestToken);
Chris@148: 
Chris@148:         // crude way to avoid leaking the data
Chris@148:         while (!m_readThread->isCancelled(m_requestToken)) {
Chris@148:             usleep(10000);
Chris@148:         }
Chris@148: 
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:         std::cerr << "cancelled " << m_requestToken << std::endl;
Chris@148: #endif
Chris@148: 
Chris@148:         if (m_spareData) free(m_spareData);
Chris@148:         m_spareData = request.data;
Chris@148:         m_readThread->done(m_requestToken);
Chris@148: 
Chris@148:         m_requestToken = -1;
Chris@148:     }
Chris@148: 
Chris@148:     if (m_fd < 0) {
Chris@148:         m_fdMutex.lock();
Chris@148:         if (m_fd < 0) resume();
Chris@148:         m_fdMutex.unlock();
Chris@148:     }
Chris@148: 
Chris@148:     request.fd = m_fd;
Chris@148:     request.mutex = &m_fdMutex;
Chris@148:     request.start = m_headerSize + rx * m_height * m_cellSize;
Chris@148:     request.size = rw * m_height * m_cellSize;
Chris@148:     request.data = (char *)realloc(m_spareData, rw * m_height * m_cellSize);
Chris@148:     MUNLOCK(request.data, rw * m_height * m_cellSize);
Chris@148:     m_spareData = 0;
Chris@148: 
Chris@148:     m_requestingX = rx;
Chris@148:     m_requestingWidth = rw;
Chris@148: 
Chris@148:     int token = m_readThread->request(request);
Chris@148: #ifdef DEBUG_MATRIX_FILE_READ_SET
Chris@148:     std::cerr << "MatrixFile::primeCache: request token is "
Chris@148:               << token << " (x = [" << rx << "], w = [" << rw << "], left = [" << goingLeft << "])" << std::endl;
Chris@148: #endif
Chris@148:     m_requestToken = token;
Chris@148: }
Chris@148: 
Chris@148: bool
Chris@148: MatrixFile::seekTo(size_t x, size_t y)
Chris@148: {
Chris@148:     if (m_fd < 0) resume();
Chris@148: 
Chris@148:     off_t off = m_headerSize + (x * m_height + y) * m_cellSize;
Chris@148: 
Chris@148:     if (::lseek(m_fd, off, SEEK_SET) == (off_t)-1) {
Chris@148:         ::perror("Seek failed");
Chris@148:         std::cerr << "ERROR: MatrixFile::seekTo(" << x << ", " << y
Chris@148:                   << ") failed" << std::endl;
Chris@148:         return false;
Chris@148:     }
Chris@148: 
Chris@148:     return true;
Chris@148: }
Chris@148: