SkThreadUtils_win.cpp revision 96fcdcc219d2a0d3579719b84b28bede76efba64 
1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkTypes.h"
9
10#include "SkThreadUtils.h"
11#include "SkThreadUtils_win.h"
12
13SkThread_WinData::SkThread_WinData(SkThread::entryPointProc entryPoint, void* data)
14    : fHandle(nullptr)
15    , fParam(data)
16    , fThreadId(0)
17    , fEntryPoint(entryPoint)
18    , fStarted(false)
19{
20    fCancelEvent = CreateEvent(
21        nullptr,  // default security attributes
22        false, //auto reset
23        false, //not signaled
24        nullptr); //no name
25}
26
27SkThread_WinData::~SkThread_WinData() {
28    CloseHandle(fCancelEvent);
29}
30
31static DWORD WINAPI thread_start(LPVOID data) {
32    SkThread_WinData* winData = static_cast<SkThread_WinData*>(data);
33
34    //See if this thread was canceled before starting.
35    if (WaitForSingleObject(winData->fCancelEvent, 0) == WAIT_OBJECT_0) {
36        return 0;
37    }
38
39    winData->fEntryPoint(winData->fParam);
40    return 0;
41}
42
43SkThread::SkThread(entryPointProc entryPoint, void* data) {
44    SkThread_WinData* winData = new SkThread_WinData(entryPoint, data);
45    fData = winData;
46
47    if (nullptr == winData->fCancelEvent) {
48        return;
49    }
50
51    winData->fHandle = CreateThread(
52        nullptr,                   // default security attributes
53        0,                      // use default stack size
54        thread_start,           // thread function name (proxy)
55        winData,                // argument to thread function (proxy args)
56        CREATE_SUSPENDED,       // create suspended so affinity can be set
57        &winData->fThreadId);   // returns the thread identifier
58}
59
60SkThread::~SkThread() {
61    if (fData != nullptr) {
62        SkThread_WinData* winData = static_cast<SkThread_WinData*>(fData);
63        // If created thread but start was never called, kill the thread.
64        if (winData->fHandle != nullptr && !winData->fStarted) {
65            if (SetEvent(winData->fCancelEvent) != 0) {
66                if (this->start()) {
67                    this->join();
68                }
69            } else {
70                //kill with prejudice
71                TerminateThread(winData->fHandle, -1);
72            }
73        }
74        delete winData;
75    }
76}
77
78bool SkThread::start() {
79    SkThread_WinData* winData = static_cast<SkThread_WinData*>(fData);
80    if (nullptr == winData->fHandle) {
81        return false;
82    }
83
84    if (winData->fStarted) {
85        return false;
86    }
87    winData->fStarted = -1 != ResumeThread(winData->fHandle);
88    return winData->fStarted;
89}
90
91void SkThread::join() {
92    SkThread_WinData* winData = static_cast<SkThread_WinData*>(fData);
93    if (nullptr == winData->fHandle || !winData->fStarted) {
94        return;
95    }
96
97    WaitForSingleObject(winData->fHandle, INFINITE);
98}
99
100static unsigned int num_bits_set(DWORD_PTR mask) {
101    unsigned int count;
102    for (count = 0; mask; ++count) {
103        mask &= mask - 1;
104    }
105    return count;
106}
107
108static unsigned int nth_set_bit(unsigned int n, DWORD_PTR mask) {
109    n %= num_bits_set(mask);
110    for (unsigned int setBitsSeen = 0, currentBit = 0; true; ++currentBit) {
111        if (mask & (static_cast<DWORD_PTR>(1) << currentBit)) {
112            ++setBitsSeen;
113            if (setBitsSeen > n) {
114                return currentBit;
115            }
116        }
117    }
118}
119
120bool SkThread::setProcessorAffinity(unsigned int processor) {
121    SkThread_WinData* winData = static_cast<SkThread_WinData*>(fData);
122    if (nullptr == winData->fHandle) {
123        return false;
124    }
125
126    DWORD_PTR processAffinityMask;
127    DWORD_PTR systemAffinityMask;
128    if (0 == GetProcessAffinityMask(GetCurrentProcess(),
129                                    &processAffinityMask,
130                                    &systemAffinityMask)) {
131        return false;
132    }
133
134    DWORD_PTR threadAffinityMask = 1 << nth_set_bit(processor, processAffinityMask);
135    return 0 != SetThreadAffinityMask(winData->fHandle, threadAffinityMask);
136}
137