Files
foobar2000-sdk/foobar2000/foo_sample/ui_and_threads.cpp
2021-12-14 00:28:25 -07:00

287 lines
11 KiB
C++

#include "stdafx.h"
#include "resource.h"
// Modern multi threading with C++
// Or: how I learned to stop worrying and love the lambdas
#include <memory> // shared_ptr
#include <libPPUI/CDialogResizeHelper.h>
#include <helpers/filetimetools.h>
#include <helpers/duration_counter.h>
#include <helpers/atl-misc.h>
namespace { // anon namespace local classes for good measure
class CDemoDialog; // forward declaration
// This is kept a separate shared_ptr'd struct because it may outlive CDemoDialog instance.
struct sharedData_t {
metadb_handle_list items;
CDemoDialog * owner; // weak reference to the owning dialog; can be only used after checking the validity by other means.
};
static const CDialogResizeHelper::Param resizeData[] = {
// Dialog resize handling matrix, defines how the controls scale with the dialog
// L T R B
{IDOK, 1,1,1,1 },
{IDCANCEL, 1,1,1,1 },
{IDC_HEADER, 0,0,1,0 },
{IDC_LIST, 0,0,1,1 },
// current position of a control is determined by initial_position + factor * (current_dialog_size - initial_dialog_size)
// where factor is the value from the table above
// applied to all four values - left, top, right, bottom
// 0,0,0,0 means that a control doesn't react to dialog resizing (aligned to top+left, no resize)
// 1,1,1,1 means that the control is aligned to bottom+right but doesn't resize
// 0,0,1,0 means that the control disregards vertical resize (aligned to top) and changes its width with the dialog
};
// Minimum/maximum size, in dialog box units; see MSDN MapDialogRect for more info about dialog box units.
// The values can be declared constant here and will be scaled appropriately depending on display DPI.
static const CRect resizeMinMax(150, 100, 1000, 1000);
class CDemoDialog : public CDialogImpl<CDemoDialog> {
public:
enum { IDD = IDD_THREADS };
CDemoDialog( metadb_handle_list_cref items ) : m_resizer(resizeData, resizeMinMax) {
m_sharedData = std::make_shared< sharedData_t > ();
m_sharedData->items = items;
m_sharedData->owner = this;
}
BEGIN_MSG_MAP_EX(CDemoDialog)
CHAIN_MSG_MAP_MEMBER(m_resizer)
MSG_WM_INITDIALOG(OnInitDialog)
COMMAND_HANDLER_EX(IDOK, BN_CLICKED, OnOK)
COMMAND_HANDLER_EX(IDCANCEL, BN_CLICKED, OnCancel)
MSG_WM_CLOSE(OnClose)
MSG_WM_DESTROY(OnDestroy)
MSG_WM_SIZE(OnSize)
END_MSG_MAP()
private:
BOOL OnInitDialog(CWindow, LPARAM) {
uSetDlgItemText(*this, IDC_HEADER, PFC_string_formatter() << "Selected: " << m_sharedData->items.get_size() << " tracks." );
m_listBox = GetDlgItem(IDC_LIST);
m_statusBar.Create(*this, NULL, TEXT(""), WS_CHILD | WS_VISIBLE);
m_statusBar.SetWindowText(L"Ready");
ShowWindow(SW_SHOW);
return TRUE; // system should set focus
}
void OnSize(UINT nType, CSize size) {
// Tell statusbar that we got resized. CDialogResizeHelper can't do this for us.
m_statusBar.SendMessage(WM_SIZE);
}
void OnDestroy() {
cancelTask();
}
void OnClose() {
// NOTE if we do not handle WM_CLOSE, WM_COMMAND with IDCANCEL will be invoked, executing our cancel handler.
// We provide our own WM_CLOSE handler to provide a different response to closing the window.
DestroyWindow();
}
void OnCancel(UINT, int, CWindow) {
// If a task is active, cancel it
// otherwise destroy the dialog
if (! cancelTask() ) {
DestroyWindow();
} else {
// Refresh UI
taskCompleted();
}
}
void OnOK(UINT, int, CWindow) {
startTask();
}
void startTask() {
cancelTask(); // cancel any running task
GetDlgItem(IDCANCEL).SetWindowText(L"Cancel");
m_statusBar.SetWindowText(L"Working...");
auto shared = m_sharedData;
auto aborter = std::make_shared<abort_callback_impl>();
m_aborter = aborter;
// New in fb2k 1.4.5: async_task_manager & splitTask
// Use fb2k::splitTask() for starting detached threads.
// In fb2k < 1.4.5, it will fall back to just starting a detached thread.
// fb2k 1.4.5+ async_task_manager cleanly deals with user exiting foobar2000 while a detached async task is running.
// Shutdown of foobar2000 process will be stalled until your task completes.
// If you use other means to ensure that the thread has finished, such as waiting for the thread to exit in your dialog's destructor, there's no need for this.
fb2k::splitTask( [aborter, shared] {
// In worker thread!
try {
work( shared, aborter );
} catch(exception_aborted) {
return; // user abort?
} catch(std::exception const & e) {
// should not really get here
logLineProc( shared, aborter, PFC_string_formatter() << "Critical error: " << e);
}
try {
mainThreadOp( aborter, [shared] {
shared->owner->taskCompleted();
} );
} catch(...) {} // mainThreadOp may throw exception_aborted
} );
}
void taskCompleted() {
m_aborter.reset();
GetDlgItem(IDCANCEL).SetWindowText(L"Close");
m_statusBar.SetWindowText(L"Finished, ready");
}
static void mainThreadOp(std::shared_ptr<abort_callback_impl> aborter, std::function<void ()> op ) {
aborter->check(); // are we getting aborted?
fb2k::inMainThread( [=] {
if ( aborter->is_set() ) return; // final user abort check
// Past this, we're main thread, the task has not been cancelled by the user and the dialog is still alive
// and any dialog methods can be safely called
op();
} );
}
static void logLineProc(std::shared_ptr<sharedData_t> shared, std::shared_ptr<abort_callback_impl> aborter, const char * line_ ) {
pfc::string8 line( line_ ); // can't hold to the const char* we got passed, we have no guarantees about its lifetime
mainThreadOp( aborter, [shared, line] {
shared->owner->logLine(line);
} );
}
static void work( std::shared_ptr<sharedData_t> shared, std::shared_ptr<abort_callback_impl> aborter ) {
// clear the log
mainThreadOp(aborter, [shared] {
shared->owner->clearLog();
} );
// A convenience wrapper that calls logLineProc()
auto log = [shared, aborter] ( const char * line ) {
logLineProc(shared, aborter, line);
};
// Use log(X) instead of logLineProc(shared, aborter, X)
for( size_t trackWalk = 0; trackWalk < shared->items.get_size(); ++ trackWalk ) {
aborter->check();
auto track = shared->items[trackWalk];
log( PFC_string_formatter() << "Track: " << track );
try {
const auto path = track->get_path();
const auto subsong = track->get_subsong_index();
// Not strictly needed, but we do it anyway
// Acquire a read lock on the file, so anyone trying to acquire a write lock will just wait till we have finished
auto lock = file_lock_manager::get()->acquire_read(path, *aborter);
{
input_decoder::ptr dec;
input_entry::g_open_for_decoding(dec, nullptr, path, *aborter);
file_info_impl info;
dec->get_info( subsong, info, *aborter );
auto title = info.meta_get("title",0);
if ( title == nullptr ) log("Untitled");
else log(PFC_string_formatter() << "Title: " << title );
if ( info.get_length() > 0 ) log(PFC_string_formatter() << "Duration: " << pfc::format_time_ex(info.get_length(),6) );
auto stats = dec->get_file_stats( *aborter );
if ( stats.m_size != filesize_invalid ) log( PFC_string_formatter() << "Size: " << pfc::format_file_size_short(stats.m_size) );
if ( stats.m_timestamp != filetimestamp_invalid ) log( PFC_string_formatter() << "Last modified: " << format_filetimestamp( stats.m_timestamp ) );
dec->initialize( subsong, input_flag_simpledecode, * aborter );
audio_chunk_impl chunk;
uint64_t numChunks = 0, numSamples = 0;
// duration_counter tool is a strictly accurate audio duration counter retaining all sample counts passed to it, immune to floatingpoint accuracy errors
duration_counter duration;
bool firstChunk = true;
while(dec->run(chunk, *aborter) ) {
if ( firstChunk ) {
auto spec = chunk.get_spec();
log(PFC_string_formatter() << "Audio sample rate: " << spec.sampleRate );
log(PFC_string_formatter() << "Audio channels: " << audio_chunk::g_formatChannelMaskDesc( spec.chanMask ) );
firstChunk = false;
}
++ numChunks;
duration += chunk;
numSamples += chunk.get_sample_count();
}
log(PFC_string_formatter() << "Decoded " << numChunks << " chunks");
log(PFC_string_formatter() << "Exact duration decoded: " << pfc::format_time_ex(duration.query(), 6) << ", " << numSamples << " samples" );
}
try {
auto aa = album_art_extractor::g_open( nullptr, path, *aborter );
if ( aa->have_entry( album_art_ids::cover_front, *aborter ) ) {
log("Album art: front cover found");
}
if ( aa->have_entry( album_art_ids::cover_back, *aborter ) ) {
log("Album art: back cover found");
}
if (aa->have_entry( album_art_ids::artist, *aborter ) ) {
log("Album art: artist picture found");
}
} catch(exception_album_art_not_found) {
} catch(exception_album_art_unsupported_format) {
}
} catch(exception_aborted) {
throw;
} catch(std::exception const & e) {
log( PFC_string_formatter() << "Failure: " << e);
}
}
log("All done.");
}
bool cancelTask() {
bool ret = false;
auto aborter = pfc::replace_null_t(m_aborter);
if (aborter) {
ret = true;
aborter->set();
logLine("Aborted by user.");
}
return ret;
}
void logLine( const char * line ) {
m_listBox.AddString( pfc::stringcvt::string_os_from_utf8(line) );
}
void clearLog() {
m_listBox.ResetContent();
}
// Worker thread aborter. It's re-created with the thread. If the task is ran more than once, each time it gets a new one.
// A commonly used alternative is to have abort_callback_impl m_aborter, and a blocking cancelTask() that waits for the thread to exit, without all the shared_ptrs and recreation of aborters.
// However that approach will freeze the UI if the worker thread is taking a long time to exit, as well as require some other shared_ptr based means for fb2k::inMainThread() ops to verify that the task is not being aborted / the dialog still exists.
// Therefore we use a shared_ptr'd aborter, which is used both to abort worker threads, and for main thread callbacks to know if the task that sent them is still valid.
std::shared_ptr<abort_callback_impl> m_aborter;
// Data shared with the worker thread. It is created only once per dialog lifetime.
std::shared_ptr< sharedData_t > m_sharedData;
CListBox m_listBox;
CStatusBarCtrl m_statusBar;
CDialogResizeHelper m_resizer;
};
}
void RunUIAndThreads(metadb_handle_list_cref data) {
// Equivalent to new CDemoDialog(data), with modeless registration and auto lifetime
fb2k::newDialog<CDemoDialog>( data );
}