commit 58153fdefd7c2e33421a1cd1aa15d02add36262a
parent 33ee09ae7126a688d380f51fe0ba4eab6ed391c1
Author: falkTX <falktx@falktx.com>
Date: Mon, 4 Jul 2022 20:42:50 +0100
Add new Runner class for a different approach to threads
Signed-off-by: falkTX <falktx@falktx.com>
Diffstat:
1 file changed, 235 insertions(+), 0 deletions(-)
diff --git a/distrho/extra/Runner.hpp b/distrho/extra/Runner.hpp
@@ -0,0 +1,235 @@
+/*
+ * DISTRHO Plugin Framework (DPF)
+ * Copyright (C) 2012-2022 Filipe Coelho <falktx@falktx.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any purpose with
+ * or without fee is hereby granted, provided that the above copyright notice and this
+ * permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
+ * TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
+ * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef DISTRHO_RUNNER_HPP_INCLUDED
+#define DISTRHO_RUNNER_HPP_INCLUDED
+
+#include "../DistrhoUtils.hpp"
+
+#ifndef DISTRHO_OS_WASM
+# include "Thread.hpp"
+#else
+# include <emscripten/emscripten.h>
+#endif
+
+START_NAMESPACE_DISTRHO
+
+// -------------------------------------------------------------------------------------------------------------------
+// Runner class
+
+/**
+ Runner class for DPF.
+
+ This is a handy class that handles "idle" time in either background or main thread,
+ whichever is more suitable to the target platform.
+ Typically background threads on desktop platforms, main thread on web.
+
+ A single function is expected to be implemented by subclasses,
+ which directly allows it to stop the runner by returning false.
+
+ You can use it for quick operations that do not need to be handled in the main thread if possible.
+ The target is to spread out execution over many runs, instead of spending a lot of time on a single task.
+ */
+class Runner
+{
+protected:
+ /*
+ * Constructor.
+ */
+ Runner(const char* const runnerName = nullptr) noexcept
+ #ifndef DISTRHO_OS_WASM
+ : fRunnerThread(this, runnerName),
+ #else
+ : fRunnerName(runnerName),
+ fShouldStop(false),
+ #endif
+ fTimeInterval(0) {}
+
+ /*
+ * Destructor.
+ */
+ virtual ~Runner() /*noexcept*/
+ {
+ DISTRHO_SAFE_ASSERT(! isRunnerActive());
+
+ stopRunner();
+ }
+
+ /*
+ * Virtual function to be implemented by the subclass.
+ * Return true to keep running, false to stop execution.
+ */
+ virtual bool run() = 0;
+
+ /*
+ * Check if the runner should stop.
+ * To be called from inside the runner to know if a stop request has been made.
+ */
+ bool shouldRunnerStop() const noexcept
+ {
+ #ifndef DISTRHO_OS_WASM
+ return fRunnerThread.shouldThreadExit();
+ #else
+ return fShouldStop;
+ #endif
+ }
+
+ // ---------------------------------------------------------------------------------------------------------------
+
+public:
+ /*
+ * Check if the runner is active.
+ */
+ bool isRunnerActive() noexcept
+ {
+ #ifndef DISTRHO_OS_WASM
+ return fRunnerThread.isThreadRunning();
+ #else
+ fShouldStop = false;
+ return true;
+ #endif
+ }
+
+ /*
+ * Start the thread.
+ */
+ bool startRunner(const uint timeIntervalMilliseconds = 0) noexcept
+ {
+ fTimeInterval = timeIntervalMilliseconds;
+ #ifndef DISTRHO_OS_WASM
+ return fRunnerThread.startThread();
+ #else
+ fShouldStop = false;
+ emscripten_async_call(_entryPoint, this, timeIntervalMilliseconds);
+ return true;
+ #endif
+ }
+
+ /*
+ * Stop the runner.
+ * This will signal the runner to stop if active, and wait until it finishes.
+ */
+ bool stopRunner() noexcept
+ {
+ #ifndef DISTRHO_OS_WASM
+ return fRunnerThread.stopThread(-1);
+ #else
+ fShouldStop = true;
+ return true;
+ #endif
+ }
+
+ /*
+ * Tell the runner to stop as soon as possible.
+ */
+ void signalRunnerShouldStop() noexcept
+ {
+ #ifndef DISTRHO_OS_WASM
+ fRunnerThread.signalThreadShouldExit();
+ #else
+ fShouldStop = true;
+ #endif
+ }
+
+ // ---------------------------------------------------------------------------------------------------------------
+
+ /*
+ * Returns the name of the runner.
+ * This is the name that gets set in the constructor.
+ */
+ const String& getRunnerName() const noexcept
+ {
+ #ifndef DISTRHO_OS_WASM
+ return fRunnerThread.getThreadName();
+ #else
+ return fRunnerName;
+ #endif
+ }
+
+ // ---------------------------------------------------------------------------------------------------------------
+
+private:
+#ifndef DISTRHO_OS_WASM
+ class RunnerThread : public Thread
+ {
+ Runner* const runner;
+
+ public:
+ RunnerThread(Runner* const r, const char* const rn)
+ : Thread(rn),
+ runner(r) {}
+
+ protected:
+ void run() override
+ {
+ const uint timeInterval = runner->fTimeInterval;
+
+ while (!shouldThreadExit())
+ {
+ bool stillRunning = false;
+
+ try {
+ stillRunning = runner->run();
+ } catch(...) {}
+
+ if (stillRunning && !shouldThreadExit())
+ {
+ if (timeInterval != 0)
+ d_msleep(timeInterval);
+
+ pthread_yield();
+ continue;
+ }
+
+ break;
+ }
+ }
+ } fRunnerThread;
+#else
+ const String fRunnerName;
+ volatile bool fShouldStop;
+
+ void _runEntryPoint() noexcept
+ {
+ if (fShouldStop)
+ return;
+
+ bool stillRunning = false;
+
+ try {
+ stillRunning = run();
+ } catch(...) {}
+
+ if (stillRunning && !fShouldStop)
+ emscripten_async_call(_entryPoint, this, fTimeInterval);
+ }
+
+ static void _entryPoint(void* const userData) noexcept
+ {
+ static_cast<Runner*>(userData)->_runEntryPoint();
+ }
+#endif
+
+ uint fTimeInterval;
+
+ DISTRHO_DECLARE_NON_COPYABLE(Runner)
+};
+
+// -------------------------------------------------------------------------------------------------------------------
+
+END_NAMESPACE_DISTRHO
+
+#endif // DISTRHO_RUNNER_HPP_INCLUDED
