mirror of
https://github.com/hajimehoshi/ebiten.git
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58366ce64d
If multiple Ebiten processes start at the same time, the file operation can cause a race condition. Add a file lock to avoid this.
88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
// Copyright 2021 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build !ebitenexternaldll
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// +build !ebitenexternaldll
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package glfw
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import (
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"bytes"
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"compress/gzip"
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"io"
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"os"
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"path/filepath"
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"github.com/gofrs/flock"
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"golang.org/x/sys/windows"
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)
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func writeDLLFile(name string) error {
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f, err := gzip.NewReader(bytes.NewReader(glfwDLLCompressed))
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if err != nil {
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return err
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}
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defer f.Close()
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out, err := os.Create(name)
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if err != nil {
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return err
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}
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defer out.Close()
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if _, err := io.Copy(out, f); err != nil {
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return err
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}
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return nil
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}
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func loadDLL() (*dll, error) {
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cachedir, err := os.UserCacheDir()
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if err != nil {
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return nil, err
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}
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dir := filepath.Join(cachedir, "ebiten")
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if err := os.MkdirAll(dir, 0755); err != nil {
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return nil, err
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}
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// Make the file operation atomic among multiple processes.
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fl := flock.New(filepath.Join(dir, glfwDLLHash+".lock"))
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fl.Lock()
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defer fl.Unlock()
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fn := filepath.Join(dir, glfwDLLHash+".dll")
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if _, err := os.Stat(fn); err != nil {
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if !os.IsNotExist(err) {
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return nil, err
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}
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// Create a DLL as a temporary file and then rename it later.
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// Without the temporary file, writing a DLL might fail in the process of writing and Ebiten cannot
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// notice that the DLL file is incomplete.
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if err := writeDLLFile(fn + ".tmp"); err != nil {
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return nil, err
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}
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if err := os.Rename(fn+".tmp", fn); err != nil {
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return nil, err
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}
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}
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return &dll{
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d: windows.NewLazyDLL(fn),
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}, nil
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}
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