global_state.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>

src/libGLESv2/global_state.cpp

//
// Copyright 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// global_state.cpp : Implements functions for querying the thread-local GL and EGL state.

#include "libGLESv2/global_state.h"

#include "common/debug.h"
#include "common/platform.h"
#include "common/tls.h"

namespace gl
{
// In single-threaded cases we can avoid a TLS lookup for the current Context.
//
// Let a global single-threaded context have 3 states: unset, set, and multi-threaded.
// Initially it is unset. Then, on MakeCurrent:
//
//  * if the ST context is unset                      -> set the global context.
//  * if the ST context is set and matches the TLS    -> set the global context.
//  * if the ST context is set and does not match TLS -> set multi-threaded mode.
//  * if in multi-threaded mode, unset and subsequently ignore the global context.
//
// Implementation-wise we can use a pointer and a boolean to represent the three modes.
Context *gSingleThreadedContext = nullptr;
bool gIsMultiThreadedContext    = false;
}  // namespace gl

namespace egl
{
namespace
{
static TLSIndex threadTLS = TLS_INVALID_INDEX;
Debug *g_Debug            = nullptr;
std::atomic<std::mutex *> g_Mutex;
static_assert(std::is_trivially_constructible<decltype(g_Mutex)>::value,
              "global mutex is not trivially constructible");
static_assert(std::is_trivially_destructible<decltype(g_Mutex)>::value,
              "global mutex is not trivially destructible");

Thread *AllocateCurrentThread()
{
    ASSERT(threadTLS != TLS_INVALID_INDEX);
    if (threadTLS == TLS_INVALID_INDEX)
    {
        return nullptr;
    }

    Thread *thread = new Thread();
    if (!SetTLSValue(threadTLS, thread))
    {
        ERR() << "Could not set thread local storage.";
        return nullptr;
    }

    return thread;
}

void AllocateDebug()
{
    // All EGL calls use a global lock, this is thread safe
    if (g_Debug == nullptr)
    {
        g_Debug = new Debug();
    }
}

void AllocateMutex()
{
    if (g_Mutex == nullptr)
    {
        std::unique_ptr<std::mutex> newMutex(new std::mutex());
        std::mutex *expected = nullptr;
        if (g_Mutex.compare_exchange_strong(expected, newMutex.get()))
        {
            newMutex.release();
        }
    }
}

}  // anonymous namespace

std::mutex &GetGlobalMutex()
{
    AllocateMutex();
    return *g_Mutex;
}

Thread *GetCurrentThread()
{
    // Create a TLS index if one has not been created for this DLL
    if (threadTLS == TLS_INVALID_INDEX)
    {
        threadTLS = CreateTLSIndex();
    }

    Thread *current = static_cast<Thread *>(GetTLSValue(threadTLS));

    // ANGLE issue 488: when the dll is loaded after thread initialization,
    // thread local storage (current) might not exist yet.
    return (current ? current : AllocateCurrentThread());
}

Debug *GetDebug()
{
    AllocateDebug();
    return g_Debug;
}

void SetContextCurrent(Thread *thread, gl::Context *context)
{
    // See above comment on gGlobalContext.
    // If the context is in multi-threaded mode, ignore the global context.
    if (!gl::gIsMultiThreadedContext)
    {
        // If the global context is unset or matches the current TLS, set the global context.
        if (gl::gSingleThreadedContext == nullptr ||
            gl::gSingleThreadedContext == thread->getContext())
        {
            gl::gSingleThreadedContext = context;
        }
        else
        {
            // If the global context is set and does not match TLS, set multi-threaded mode.
            gl::gSingleThreadedContext  = nullptr;
            gl::gIsMultiThreadedContext = true;
        }
    }
    thread->setCurrent(context);
}
}  // namespace egl

#ifdef ANGLE_PLATFORM_WINDOWS
namespace egl
{

namespace
{

bool DeallocateCurrentThread()
{
    Thread *thread = static_cast<Thread *>(GetTLSValue(threadTLS));
    SafeDelete(thread);
    return SetTLSValue(threadTLS, nullptr);
}

void DeallocateDebug()
{
    SafeDelete(g_Debug);
}

void DeallocateMutex()
{
    std::mutex *mutex = g_Mutex.exchange(nullptr);
    {
        // Wait for the mutex to become released by other threads before deleting.
        std::lock_guard<std::mutex> lock(*mutex);
    }
    SafeDelete(mutex);
}

bool InitializeProcess()
{
    ASSERT(g_Debug == nullptr);
    AllocateDebug();

    AllocateMutex();

    threadTLS = CreateTLSIndex();
    if (threadTLS == TLS_INVALID_INDEX)
    {
        return false;
    }

    return AllocateCurrentThread() != nullptr;
}

bool TerminateProcess()
{
    DeallocateDebug();

    DeallocateMutex();

    if (!DeallocateCurrentThread())
    {
        return false;
    }

    if (threadTLS != TLS_INVALID_INDEX)
    {
        TLSIndex tlsCopy = threadTLS;
        threadTLS        = TLS_INVALID_INDEX;

        if (!DestroyTLSIndex(tlsCopy))
        {
            return false;
        }
    }

    return true;
}

}  // anonymous namespace

}  // namespace egl

extern "C" BOOL WINAPI DllMain(HINSTANCE, DWORD reason, LPVOID)
{
    switch (reason)
    {
        case DLL_PROCESS_ATTACH:
            return static_cast<BOOL>(egl::InitializeProcess());

        case DLL_THREAD_ATTACH:
            return static_cast<BOOL>(egl::AllocateCurrentThread() != nullptr);

        case DLL_THREAD_DETACH:
            return static_cast<BOOL>(egl::DeallocateCurrentThread());

        case DLL_PROCESS_DETACH:
            return static_cast<BOOL>(egl::TerminateProcess());
    }

    return TRUE;
}
#endif  // ANGLE_PLATFORM_WINDOWS

kc3-lang/angle/src/libGLESv2/global_state.cpp

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kc3-lang/angle /src/libGLESv2/global_state.cpp