40 lines
919 B
Go
40 lines
919 B
Go
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package fs
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import (
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"io"
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"os"
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)
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// SeekWrapper wraps an io.Reader with a basic Seek method which
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// returns the Size attribute.
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//
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// This is used for google.golang.org/api/googleapi/googleapi.go
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// to detect the length (see getReaderSize function)
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//
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// Without this the getReaderSize function reads the entire file into
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// memory to find its length.
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type SeekWrapper struct {
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In io.Reader
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Size int64
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}
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// Read bytes from the object - see io.Reader
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func (file *SeekWrapper) Read(p []byte) (n int, err error) {
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return file.In.Read(p)
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}
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// Seek - minimal implementation for Google API length detection
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func (file *SeekWrapper) Seek(offset int64, whence int) (int64, error) {
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switch whence {
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case os.SEEK_CUR:
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return 0, nil
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case os.SEEK_END:
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return file.Size, nil
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}
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return 0, nil
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}
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// Interfaces that SeekWrapper implements
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var _ io.Reader = (*SeekWrapper)(nil)
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var _ io.Seeker = (*SeekWrapper)(nil)
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