99 lines
1.9 KiB
Go
99 lines
1.9 KiB
Go
package goldsmith
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import (
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"encoding/binary"
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"fmt"
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"hash/crc32"
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"os"
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"path/filepath"
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"sort"
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)
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type cache struct {
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baseDir string
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}
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func (cache *cache) retrieveFile(context *Context, outputPath string, inputFiles []*File) (*File, error) {
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cachePath, err := cache.buildCachePath(context, outputPath, inputFiles)
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if err != nil {
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return nil, err
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}
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outputFile, err := context.CreateFileFromAsset(outputPath, cachePath)
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if err != nil {
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if os.IsNotExist(err) {
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return nil, nil
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}
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return nil, err
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}
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return outputFile, nil
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}
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func (cache *cache) storeFile(context *Context, outputFile *File, inputFiles []*File) error {
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cachePath, err := cache.buildCachePath(context, outputFile.Path(), inputFiles)
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if err != nil {
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return err
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}
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if err := os.MkdirAll(cache.baseDir, 0755); err != nil {
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return err
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}
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fp, err := os.Create(cachePath)
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if err != nil {
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return err
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}
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defer fp.Close()
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offset, err := outputFile.Seek(0, os.SEEK_CUR)
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if err != nil {
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return err
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}
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if _, err := outputFile.Seek(0, os.SEEK_SET); err != nil {
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return err
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}
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if _, err := outputFile.WriteTo(fp); err != nil {
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return err
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}
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if _, err := outputFile.Seek(offset, os.SEEK_SET); 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 (cache *cache) buildCachePath(context *Context, outputPath string, inputFiles []*File) (string, error) {
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uintBuff := make([]byte, 4)
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binary.LittleEndian.PutUint32(uintBuff, context.hash)
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hasher := crc32.NewIEEE()
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hasher.Write(uintBuff)
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hasher.Write([]byte(outputPath))
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sort.Sort(FilesByPath(inputFiles))
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for _, inputFile := range inputFiles {
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fileHash, err := inputFile.hash()
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if err != nil {
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return "", err
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}
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binary.LittleEndian.PutUint32(uintBuff, fileHash)
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hasher.Write(uintBuff)
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hasher.Write([]byte(inputFile.Path()))
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}
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cachePath := filepath.Join(cache.baseDir, fmt.Sprintf(
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"gs_%.8x%s",
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hasher.Sum32(),
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filepath.Ext(outputPath),
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))
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return cachePath, nil
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}
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