view data/fileio/FileReadThread.cpp @ 1196:c7b9c902642f spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#include "FileReadThread.h"

#include "base/Profiler.h"
#include "base/Thread.h"

#include <iostream>
#include <unistd.h>
#include <cstdio>

//#define DEBUG_FILE_READ_THREAD 1

FileReadThread::FileReadThread() :
    m_nextToken(0),
    m_exiting(false)
{
}

void
FileReadThread::run()
{
    MutexLocker locker(&m_mutex, "FileReadThread::run::m_mutex");

    while (!m_exiting) {
        if (m_queue.empty()) {
            m_condition.wait(&m_mutex, 1000);
        } else {
            process();
        }
        notifyCancelled();
    }

    notifyCancelled();

#ifdef DEBUG_FILE_READ_THREAD
    SVDEBUG << "FileReadThread::run() exiting" << endl;
#endif
}

void
FileReadThread::finish()
{
#ifdef DEBUG_FILE_READ_THREAD
    SVDEBUG << "FileReadThread::finish()" << endl;
#endif

    {
        MutexLocker locker(&m_mutex, "FileReadThread::finish::m_mutex");

        while (!m_queue.empty()) {
            m_cancelledRequests[m_queue.begin()->first] = m_queue.begin()->second;
            m_newlyCancelled.insert(m_queue.begin()->first);
            m_queue.erase(m_queue.begin());
        }
        
        m_exiting = true;
    }

    m_condition.wakeAll();

#ifdef DEBUG_FILE_READ_THREAD
    SVDEBUG << "FileReadThread::finish() exiting" << endl;
#endif
}

int
FileReadThread::request(const Request &request)
{
    int token;

    {
        MutexLocker locker(&m_mutex, "FileReadThread::request::m_mutex");
    
        token = m_nextToken++;
        m_queue[token] = request;
    }

    m_condition.wakeAll();

    return token;
}

void
FileReadThread::cancel(int token)
{
    {
        MutexLocker locker(&m_mutex, "FileReadThread::cancel::m_mutex");

        if (m_queue.find(token) != m_queue.end()) {
            m_cancelledRequests[token] = m_queue[token];
            m_queue.erase(token);
            m_newlyCancelled.insert(token);
        } else if (m_readyRequests.find(token) != m_readyRequests.end()) {
            m_cancelledRequests[token] = m_readyRequests[token];
            m_readyRequests.erase(token);
        } else {
            cerr << "WARNING: FileReadThread::cancel: token " << token << " not found" << endl;
        }
    }

#ifdef DEBUG_FILE_READ_THREAD
    SVDEBUG << "FileReadThread::cancel(" << token << ") waking condition" << endl;
#endif

    m_condition.wakeAll();
}

bool
FileReadThread::isReady(int token)
{
    MutexLocker locker(&m_mutex, "FileReadThread::isReady::m_mutex");

    bool ready = m_readyRequests.find(token) != m_readyRequests.end();

    return ready;
}

bool
FileReadThread::isCancelled(int token)
{
    MutexLocker locker(&m_mutex, "FileReadThread::isCancelled::m_mutex");

    bool cancelled = 
        m_cancelledRequests.find(token) != m_cancelledRequests.end() &&
        m_newlyCancelled.find(token) == m_newlyCancelled.end();

    return cancelled;
}

bool
FileReadThread::haveRequest(int token)
{
    MutexLocker locker(&m_mutex, "FileReadThread::haveRequest::m_mutex");

    bool found = false;

    if (m_queue.find(token) != m_queue.end()) {
        found = true;
    } else if (m_cancelledRequests.find(token) != m_cancelledRequests.end()) {
        found = true;
    } else if (m_readyRequests.find(token) != m_readyRequests.end()) {
        found = true;
    }

    return found;
}

bool
FileReadThread::getRequest(int token, Request &request)
{
    MutexLocker locker(&m_mutex, "FileReadThread::getRequest::m_mutex");

    bool found = false;

    if (m_queue.find(token) != m_queue.end()) {
        request = m_queue[token];
        found = true;
    } else if (m_cancelledRequests.find(token) != m_cancelledRequests.end()) {
        request = m_cancelledRequests[token];
        found = true;
    } else if (m_readyRequests.find(token) != m_readyRequests.end()) {
        request = m_readyRequests[token];
        found = true;
    }

    return found;
}

void
FileReadThread::done(int token)
{
    MutexLocker locker(&m_mutex, "FileReadThread::done::m_mutex");

    bool found = false;

    if (m_cancelledRequests.find(token) != m_cancelledRequests.end()) {
        m_cancelledRequests.erase(token);
        m_newlyCancelled.erase(token);
        found = true;
    } else if (m_readyRequests.find(token) != m_readyRequests.end()) {
        m_readyRequests.erase(token);
        found = true;
    } else if (m_queue.find(token) != m_queue.end()) {
        cerr << "WARNING: FileReadThread::done(" << token << "): request is still in queue (wait or cancel it)" << endl;
    }

    if (!found) {
        cerr << "WARNING: FileReadThread::done(" << token << "): request not found" << endl;
    }
}

void
FileReadThread::process()
{
    // entered with m_mutex locked and m_queue non-empty

    Profiler profiler("FileReadThread::process", true);

    int token = m_queue.begin()->first;
    Request request = m_queue.begin()->second;

    m_mutex.unlock();

#ifdef DEBUG_FILE_READ_THREAD
    SVDEBUG << "FileReadThread::process: reading " << request.start << ", " << request.size << " on " << request.fd << endl;
#endif

    bool successful = false;
    bool seekFailed = false;
    ssize_t r = 0;

    { 
        MutexLocker rlocker(request.mutex, "FileReadThread::process::request.mutex");

        if (::lseek(request.fd, request.start, SEEK_SET) == (off_t)-1) {
            seekFailed = true;
        } else {
        
            // if request.size is large, we want to avoid making a single
            // system call to read it all as it may block too much
            
            static const size_t blockSize = 256 * 1024;
            
            size_t size = request.size;
            char *destination = request.data;
            
            while (size > 0) {
                size_t readSize = size;
                if (readSize > blockSize) readSize = blockSize;
                ssize_t br = ::read(request.fd, destination, readSize);
                if (br < 0) { 
                    r = br;
                    break;
                } else {
                    r += br;
                    if (br < ssize_t(readSize)) break;
                }
                destination += readSize;
                size -= readSize;
            }
        }
    }

    if (seekFailed) {
        ::perror("Seek failed");
        cerr << "ERROR: FileReadThread::process: seek to "
                  << request.start << " failed" << endl;
        request.size = 0;
    } else {
        if (r < 0) {
            ::perror("ERROR: FileReadThread::process: Read failed");
            cerr << "ERROR: FileReadThread::process: read of "
                      << request.size << " at "
                      << request.start << " failed" << endl;
            request.size = 0;
        } else if (r < ssize_t(request.size)) {
            cerr << "WARNING: FileReadThread::process: read "
                      << request.size << " returned only " << r << " bytes"
                      << endl;
            request.size = r;
            usleep(100000);
        } else {
            successful = true;
        }
    }
        
    // Check that the token hasn't been cancelled and the thread
    // hasn't been asked to finish
    
    m_mutex.lock();

    request.successful = successful;
        
    if (m_queue.find(token) != m_queue.end() && !m_exiting) {
        m_queue.erase(token);
        m_readyRequests[token] = request;
#ifdef DEBUG_FILE_READ_THREAD
        SVDEBUG << "FileReadThread::process: done, marking as ready (success = " << m_readyRequests[token].successful << ")" << endl;
#endif
    } else {
#ifdef DEBUG_FILE_READ_THREAD
        if (m_exiting) {
            SVDEBUG << "FileReadThread::process: exiting" << endl;
        } else {
            SVDEBUG << "FileReadThread::process: request disappeared" << endl;
        }
#endif
    }
}

void
FileReadThread::notifyCancelled()
{
    // entered with m_mutex locked

    while (!m_newlyCancelled.empty()) {

        int token = *m_newlyCancelled.begin();

#ifdef DEBUG_FILE_READ_THREAD
        SVDEBUG << "FileReadThread::notifyCancelled: token " << token << endl;
#endif

        m_newlyCancelled.erase(token);
    }
}