95 lines
1.8 KiB
Go
95 lines
1.8 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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"io"
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"os"
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"path/filepath"
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"sort"
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"strings"
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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 (self *cache) retrieveFile(context *Context, outputPath string, inputFiles []*File) (*File, error) {
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cachePath, err := self.buildCachePath(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 (self *cache) storeFile(outputFile *File, inputFiles []*File) error {
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cachePath, err := self.buildCachePath(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(self.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, io.SeekCurrent)
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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, io.SeekStart); 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, io.SeekStart); 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 (self *cache) buildCachePath(outputPath string, inputFiles []*File) (string, error) {
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hasher := crc32.NewIEEE()
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hasher.Write([]byte(outputPath))
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sort.Slice(inputFiles, func(i, j int) bool {
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return strings.Compare(inputFiles[i].Path(), inputFiles[j].Path()) < 0
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})
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for _, inputFile := range inputFiles {
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modTimeBuff := make([]byte, 8)
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binary.LittleEndian.PutUint64(modTimeBuff, uint64(inputFile.ModTime().UnixNano()))
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hasher.Write([]byte(inputFile.Path()))
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hasher.Write(modTimeBuff)
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}
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cachePath := filepath.Join(self.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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