From f40e1fd840fcf05b4c8cf87dc1da734b171e99ef Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Thu, 5 Oct 2017 18:09:58 -0400
Subject: [PATCH] Commutes the best-effort updater into C++11.
---
Concurrency/BestEffortUpdater.cpp | 58 +++++++++++++
Concurrency/BestEffortUpdater.hpp | 61 ++++++++++++++
.../Clock Signal.xcodeproj/project.pbxproj | 14 +++-
.../Updater/CSBestEffortUpdater.h | 2 +-
.../Updater/CSBestEffortUpdater.m | 84 -------------------
.../Updater/CSBestEffortUpdater.mm | 73 ++++++++++++++++
6 files changed, 203 insertions(+), 89 deletions(-)
create mode 100644 Concurrency/BestEffortUpdater.cpp
create mode 100644 Concurrency/BestEffortUpdater.hpp
delete mode 100644 OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.m
create mode 100644 OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm
diff --git a/Concurrency/BestEffortUpdater.cpp b/Concurrency/BestEffortUpdater.cpp
new file mode 100644
index 000000000..716303ca5
--- /dev/null
+++ b/Concurrency/BestEffortUpdater.cpp
@@ -0,0 +1,58 @@
+//
+// BestEffortUpdater.cpp
+// Clock Signal
+//
+// Created by Thomas Harte on 04/10/2017.
+// Copyright © 2017 Thomas Harte. All rights reserved.
+//
+
+#include "BestEffortUpdater.hpp"
+
+#include <cmath>
+
+using namespace Concurrency;
+
+void BestEffortUpdater::update() {
+ if(!update_is_ongoing_.test_and_set()) {
+ async_task_queue_.enqueue([this]() {
+ std::chrono::time_point<std::chrono::high_resolution_clock> now = std::chrono::high_resolution_clock::now();
+ auto elapsed = now - previous_time_point_;
+ previous_time_point_ = now;
+
+ if(has_previous_time_point_) {
+ int64_t timestamp = std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed).count();
+ double cycles = ((timestamp * clock_rate_) / 1e9) + error_;
+ error_ = fmod(cycles, 1.0);
+
+ if(delegate_) {
+ delegate_->update(this, (int)cycles, has_skipped_);
+ }
+ has_skipped_ = false;
+ } else {
+ has_previous_time_point_ = true;
+ }
+
+ update_is_ongoing_.clear();
+ });
+ } else {
+ async_task_queue_.enqueue([this]() {
+ has_skipped_ = true;
+ });
+ }
+}
+
+void BestEffortUpdater::flush() {
+ async_task_queue_.flush();
+}
+
+void BestEffortUpdater::set_delegate(Delegate *delegate) {
+ async_task_queue_.enqueue([this, delegate]() {
+ delegate_ = delegate;
+ });
+}
+
+void BestEffortUpdater::set_clock_rate(double clock_rate) {
+ async_task_queue_.enqueue([this, clock_rate]() {
+ this->clock_rate_ = clock_rate;
+ });
+}
diff --git a/Concurrency/BestEffortUpdater.hpp b/Concurrency/BestEffortUpdater.hpp
new file mode 100644
index 000000000..33b267bbb
--- /dev/null
+++ b/Concurrency/BestEffortUpdater.hpp
@@ -0,0 +1,61 @@
+//
+// BestEffortUpdater.hpp
+// Clock Signal
+//
+// Created by Thomas Harte on 04/10/2017.
+// Copyright © 2017 Thomas Harte. All rights reserved.
+//
+
+#ifndef BestEffortUpdater_hpp
+#define BestEffortUpdater_hpp
+
+#include <atomic>
+#include <chrono>
+
+#include "AsyncTaskQueue.hpp"
+
+namespace Concurrency {
+
+/*!
+ Accepts timing cues from multiple threads and ensures that a delegate receives calls to total
+ a certain number of cycles per second, that those calls are strictly serialised, and that no
+ backlog of calls accrues.
+*/
+class BestEffortUpdater {
+ public:
+ /// A delegate receives timing cues.
+ struct Delegate {
+ virtual void update(BestEffortUpdater *updater, int cycles, bool did_skip_previous_update) = 0;
+ };
+
+ /// Sets the current delegate.
+ void set_delegate(Delegate *);
+
+ /// Sets the clock rate of the delegate.
+ void set_clock_rate(double clock_rate);
+
+ /*!
+ If the delegate is not currently in the process of an `update` call, calls it now to catch up to the current time.
+ The call is asynchronous; this method will return immediately.
+ */
+ void update();
+
+ /// Blocks until any ongoing update is complete.
+ void flush();
+
+ private:
+ std::atomic_flag update_is_ongoing_;
+ AsyncTaskQueue async_task_queue_;
+
+ std::chrono::time_point<std::chrono::high_resolution_clock> previous_time_point_;
+ bool has_previous_time_point_ = false;
+ double error_ = 0.0;
+ bool has_skipped_ = false;
+
+ Delegate *delegate_ = nullptr;
+ double clock_rate_ = 1.0;
+};
+
+}
+
+#endif /* BestEffortUpdater_hpp */
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index f15c35951..0cdf62929 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
@@ -106,6 +106,7 @@
4B79E4461E3AF38600141F11 /* floppy525.png in Resources */ = {isa = PBXBuildFile; fileRef = 4B79E4431E3AF38600141F11 /* floppy525.png */; };
4B7BC7F51F58F27800D1B1B4 /* 6502AllRAM.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B6A4C911F58F09E00E3F787 /* 6502AllRAM.cpp */; };
4B7BC7F61F58F7D200D1B1B4 /* 6502Base.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B6A4C951F58F09E00E3F787 /* 6502Base.cpp */; };
+ 4B80AD001F85CACA00176895 /* BestEffortUpdater.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B80ACFE1F85CAC900176895 /* BestEffortUpdater.cpp */; };
4B8334821F5D9FF70097E338 /* PartialMachineCycle.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8334811F5D9FF70097E338 /* PartialMachineCycle.cpp */; };
4B8334841F5DA0360097E338 /* Z80Storage.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8334831F5DA0360097E338 /* Z80Storage.cpp */; };
4B8334861F5DA3780097E338 /* 6502Storage.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B8334851F5DA3780097E338 /* 6502Storage.cpp */; };
@@ -442,7 +443,7 @@
4BD3A30B1EE755C800B5B501 /* Video.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BD3A3091EE755C800B5B501 /* Video.cpp */; };
4BD468F71D8DF41D0084958B /* 1770.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BD468F51D8DF41D0084958B /* 1770.cpp */; };
4BD4A8D01E077FD20020D856 /* PCMTrackTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4BD4A8CF1E077FD20020D856 /* PCMTrackTests.mm */; };
- 4BD5F1951D13528900631CD1 /* CSBestEffortUpdater.m in Sources */ = {isa = PBXBuildFile; fileRef = 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.m */; };
+ 4BD5F1951D13528900631CD1 /* CSBestEffortUpdater.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.mm */; };
4BDDBA991EF3451200347E61 /* Z80MachineCycleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BDDBA981EF3451200347E61 /* Z80MachineCycleTests.swift */; };
4BE77A2E1D84ADFB00BC3827 /* File.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BE77A2C1D84ADFB00BC3827 /* File.cpp */; };
4BE7C9181E3D397100A5496D /* TIA.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BE7C9161E3D397100A5496D /* TIA.cpp */; };
@@ -674,6 +675,8 @@
4B79E4411E3AF38600141F11 /* cassette.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = cassette.png; sourceTree = "<group>"; };
4B79E4421E3AF38600141F11 /* floppy35.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = floppy35.png; sourceTree = "<group>"; };
4B79E4431E3AF38600141F11 /* floppy525.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = floppy525.png; sourceTree = "<group>"; };
+ 4B80ACFE1F85CAC900176895 /* BestEffortUpdater.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = BestEffortUpdater.cpp; path = ../../Concurrency/BestEffortUpdater.cpp; sourceTree = "<group>"; };
+ 4B80ACFF1F85CACA00176895 /* BestEffortUpdater.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = BestEffortUpdater.hpp; path = ../../Concurrency/BestEffortUpdater.hpp; sourceTree = "<group>"; };
4B8334811F5D9FF70097E338 /* PartialMachineCycle.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PartialMachineCycle.cpp; sourceTree = "<group>"; };
4B8334831F5DA0360097E338 /* Z80Storage.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Z80Storage.cpp; sourceTree = "<group>"; };
4B8334851F5DA3780097E338 /* 6502Storage.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = 6502Storage.cpp; sourceTree = "<group>"; };
@@ -1073,7 +1076,7 @@
4BD468F61D8DF41D0084958B /* 1770.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = 1770.hpp; path = 1770/1770.hpp; sourceTree = "<group>"; };
4BD4A8CF1E077FD20020D856 /* PCMTrackTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = PCMTrackTests.mm; sourceTree = "<group>"; };
4BD5F1931D13528900631CD1 /* CSBestEffortUpdater.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CSBestEffortUpdater.h; path = Updater/CSBestEffortUpdater.h; sourceTree = "<group>"; };
- 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = CSBestEffortUpdater.m; path = Updater/CSBestEffortUpdater.m; sourceTree = "<group>"; };
+ 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = CSBestEffortUpdater.mm; path = Updater/CSBestEffortUpdater.mm; sourceTree = "<group>"; };
4BD9137D1F311BC5009BCF85 /* i8255.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = i8255.hpp; path = 8255/i8255.hpp; sourceTree = "<group>"; };
4BDDBA981EF3451200347E61 /* Z80MachineCycleTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Z80MachineCycleTests.swift; sourceTree = "<group>"; };
4BE77A2C1D84ADFB00BC3827 /* File.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = File.cpp; path = ../../StaticAnalyser/Commodore/File.cpp; sourceTree = "<group>"; };
@@ -1390,6 +1393,8 @@
children = (
4B3940E51DA83C8300427841 /* AsyncTaskQueue.cpp */,
4B3940E61DA83C8300427841 /* AsyncTaskQueue.hpp */,
+ 4B80ACFE1F85CAC900176895 /* BestEffortUpdater.cpp */,
+ 4B80ACFF1F85CACA00176895 /* BestEffortUpdater.hpp */,
);
name = Concurrency;
sourceTree = "<group>";
@@ -2362,7 +2367,7 @@
isa = PBXGroup;
children = (
4BD5F1931D13528900631CD1 /* CSBestEffortUpdater.h */,
- 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.m */,
+ 4BD5F1941D13528900631CD1 /* CSBestEffortUpdater.mm */,
);
name = Updater;
sourceTree = "<group>";
@@ -2939,7 +2944,7 @@
4B8FE2221DA19FB20090D3CE /* MachinePanel.swift in Sources */,
4B4518A41F75FD1C00926311 /* OricMFMDSK.cpp in Sources */,
4BBB14311CD2CECE00BDB55C /* IntermediateShader.cpp in Sources */,
- 4BD5F1951D13528900631CD1 /* CSBestEffortUpdater.m in Sources */,
+ 4BD5F1951D13528900631CD1 /* CSBestEffortUpdater.mm in Sources */,
4B96F7221D75119A0058BB2D /* Tape.cpp in Sources */,
4B4518811F75E91A00926311 /* PCMPatchedTrack.cpp in Sources */,
4B8805F71DCFF6C9003085B1 /* Commodore.cpp in Sources */,
@@ -2982,6 +2987,7 @@
4B4518821F75E91A00926311 /* PCMSegment.cpp in Sources */,
4BE7C9181E3D397100A5496D /* TIA.cpp in Sources */,
4B1E85751D170228001EF87D /* Typer.cpp in Sources */,
+ 4B80AD001F85CACA00176895 /* BestEffortUpdater.cpp in Sources */,
4B2E2D9D1C3A070400138695 /* Electron.cpp in Sources */,
4B3940E71DA83C8300427841 /* AsyncTaskQueue.cpp in Sources */,
4B69FB3D1C4D908A00B5F0AA /* Tape.cpp in Sources */,
diff --git a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.h b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.h
index 5bf76a152..7130f3636 100644
--- a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.h
+++ b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.h
@@ -22,7 +22,7 @@
@property (nonatomic, assign) double clockRate;
@property (nonatomic, assign) BOOL runAsUnlimited;
-@property (atomic, weak) id<CSBestEffortUpdaterDelegate> delegate;
+@property (nonatomic, weak) id<CSBestEffortUpdaterDelegate> delegate;
- (void)update;
- (void)flush;
diff --git a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.m b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.m
deleted file mode 100644
index 67b44d18c..000000000
--- a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.m
+++ /dev/null
@@ -1,84 +0,0 @@
-//
-// CSBestEffortUpdater.m
-// Clock Signal
-//
-// Created by Thomas Harte on 16/06/2016.
-// Copyright © 2016 Thomas Harte. All rights reserved.
-//
-
-#import "CSBestEffortUpdater.h"
-
-#include <stdatomic.h>
-
-@implementation CSBestEffortUpdater
-{
- // these are inherently handled only by thread-safe constructions
- atomic_flag _updateIsOngoing;
- dispatch_queue_t _serialDispatchQueue;
-
- // these are permitted for modification on _serialDispatchQueue only
- NSTimeInterval _previousTimeInterval;
- NSTimeInterval _cyclesError;
- BOOL _hasSkipped;
- id<CSBestEffortUpdaterDelegate> _delegate;
-}
-
-- (instancetype)init
-{
- if(self = [super init])
- {
- _serialDispatchQueue = dispatch_queue_create("Best Effort Updater", DISPATCH_QUEUE_SERIAL);
-
- // This is a workaround for assigning the correct initial value within Objective-C's form.
- atomic_flag initialFlagValue = ATOMIC_FLAG_INIT;
- _updateIsOngoing = initialFlagValue;
- }
- return self;
-}
-
-- (void)update {
- // Always post an -openGLView:didUpdateToTime: if a previous one isn't still ongoing. This is the hook upon which the substantial processing occurs.
- if(!atomic_flag_test_and_set(&_updateIsOngoing)) {
- dispatch_async(_serialDispatchQueue, ^{
- NSTimeInterval timeInterval = [NSDate timeIntervalSinceReferenceDate];
- if(_previousTimeInterval > DBL_EPSILON && timeInterval > _previousTimeInterval) {
- NSTimeInterval timeToRunFor = timeInterval - _previousTimeInterval;
- double cyclesToRunFor = timeToRunFor * self.clockRate + _cyclesError;
-
- _cyclesError = fmod(cyclesToRunFor, 1.0);
- NSUInteger integerCyclesToRunFor = (NSUInteger)MIN(cyclesToRunFor, self.clockRate * 0.5);
-
- // treat 'unlimited' as running at a factor of 10
- if(self.runAsUnlimited) integerCyclesToRunFor *= 10;
- [_delegate bestEffortUpdater:self runForCycles:integerCyclesToRunFor didSkipPreviousUpdate:_hasSkipped];
- }
- _previousTimeInterval = timeInterval;
- _hasSkipped = NO;
- atomic_flag_clear(&_updateIsOngoing);
- });
- } else {
- dispatch_async(_serialDispatchQueue, ^{
- _hasSkipped = YES;
- });
- }
-}
-
-- (void)flush {
- dispatch_sync(_serialDispatchQueue, ^{});
-}
-
-- (void)setDelegate:(id<CSBestEffortUpdaterDelegate>)delegate {
- dispatch_sync(_serialDispatchQueue, ^{
- _delegate = delegate;
- });
-}
-
-- (id<CSBestEffortUpdaterDelegate>)delegate {
- __block id<CSBestEffortUpdaterDelegate> delegate;
- dispatch_sync(_serialDispatchQueue, ^{
- delegate = _delegate;
- });
- return delegate;
-}
-
-@end
diff --git a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm
new file mode 100644
index 000000000..fdcb9dc9f
--- /dev/null
+++ b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm
@@ -0,0 +1,73 @@
+//
+// CSBestEffortUpdater.m
+// Clock Signal
+//
+// Created by Thomas Harte on 16/06/2016.
+// Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+#import "CSBestEffortUpdater.h"
+
+#include "BestEffortUpdater.hpp"
+
+struct UpdaterDelegate: public Concurrency::BestEffortUpdater::Delegate {
+ __weak id<CSBestEffortUpdaterDelegate> delegate;
+ NSLock *delegateLock;
+
+ void update(Concurrency::BestEffortUpdater *updater, int cycles, bool did_skip_previous_update) {
+ [delegateLock lock];
+ [delegate bestEffortUpdater:nil runForCycles:(NSUInteger)cycles didSkipPreviousUpdate:did_skip_previous_update];
+ [delegateLock unlock];
+ }
+};
+
+@implementation CSBestEffortUpdater {
+ Concurrency::BestEffortUpdater _updater;
+ UpdaterDelegate _updaterDelegate;
+ NSLock *_delegateLock;
+}
+
+- (instancetype)init {
+ self = [super init];
+ if(self) {
+ _delegateLock = [[NSLock alloc] init];
+ _updaterDelegate.delegateLock = _delegateLock;
+ _updater.set_delegate(&_updaterDelegate);
+ }
+ return self;
+}
+
+- (void)dealloc {
+ _updater.flush();
+}
+
+- (void)update {
+ _updater.update();
+}
+
+- (void)flush {
+ _updater.flush();
+}
+
+- (void)setClockRate:(double)clockRate {
+ _clockRate = clockRate;
+ _updater.set_clock_rate(clockRate);
+}
+
+- (void)setDelegate:(id<CSBestEffortUpdaterDelegate>)delegate {
+ [_delegateLock lock];
+ _updaterDelegate.delegate = delegate;
+ [_delegateLock unlock];
+}
+
+- (id<CSBestEffortUpdaterDelegate>)delegate {
+ id<CSBestEffortUpdaterDelegate> delegate;
+
+ [_delegateLock lock];
+ delegate = _updaterDelegate.delegate;
+ [_delegateLock unlock];
+
+ return delegate;
+}
+
+@end