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d51e9d1b98
This commit changes the signatures for repository.LoadAndDecrypt and utils.LoadAll to allow passing in a []byte as the buffer to use. This buffer is enlarged as needed, and returned back to the caller for further use. In later commits, this allows reducing allocations by reusing a buffer for multiple calls, e.g. in a worker function.
64 lines
1.7 KiB
Go
64 lines
1.7 KiB
Go
package backend
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import (
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"bytes"
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"context"
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"io"
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"github.com/restic/restic/internal/restic"
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)
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// LoadAll reads all data stored in the backend for the handle into the given
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// buffer, which is truncated. If the buffer is not large enough or nil, a new
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// one is allocated.
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func LoadAll(ctx context.Context, buf []byte, be restic.Backend, h restic.Handle) ([]byte, error) {
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err := be.Load(ctx, h, 0, 0, func(rd io.Reader) error {
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// make sure this is idempotent, in case an error occurs this function may be called multiple times!
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wr := bytes.NewBuffer(buf[:0])
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_, cerr := io.Copy(wr, rd)
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if cerr != nil {
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return cerr
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}
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buf = wr.Bytes()
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return nil
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})
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if err != nil {
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return nil, err
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}
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return buf, nil
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}
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// LimitedReadCloser wraps io.LimitedReader and exposes the Close() method.
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type LimitedReadCloser struct {
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io.ReadCloser
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io.Reader
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}
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// Read reads data from the limited reader.
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func (l *LimitedReadCloser) Read(p []byte) (int, error) {
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return l.Reader.Read(p)
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}
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// LimitReadCloser returns a new reader wraps r in an io.LimitReader, but also
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// exposes the Close() method.
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func LimitReadCloser(r io.ReadCloser, n int64) *LimitedReadCloser {
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return &LimitedReadCloser{ReadCloser: r, Reader: io.LimitReader(r, n)}
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}
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// DefaultLoad implements Backend.Load using lower-level openReader func
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func DefaultLoad(ctx context.Context, h restic.Handle, length int, offset int64,
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openReader func(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error),
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fn func(rd io.Reader) error) error {
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rd, err := openReader(ctx, h, length, offset)
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if err != nil {
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return err
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}
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err = fn(rd)
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if err != nil {
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rd.Close() // ignore secondary errors closing the reader
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return err
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}
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return rd.Close()
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}
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