mirror of
https://github.com/vbatts/tar-split.git
synced 2025-03-20 23:34:08 +00:00
Vincent Batts
c8b16f6803
The feature of golang having source in a project path with "internal" makes the code only able to be imported by the project itself. https://docs.google.com/document/d/1e8kOo3r51b2BWtTs_1uADIA5djfXhPT36s6eHVRIvaU/edit?tab=t.0 Since we have this carried version of `archive/tar` with our byte accounting patches, it is also means the version of archive/tar has not kept up with upstream. our tar-split libraries do not even utilize all the function calls of our carried archive/tar, so might as well limit anyone else in the world from calling them as well. Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
57 lines
1.7 KiB
Go
57 lines
1.7 KiB
Go
package asm
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import (
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"bytes"
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"fmt"
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"io"
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"github.com/vbatts/tar-split/internal/archive/tar"
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"github.com/vbatts/tar-split/tar/storage"
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)
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// IterateHeaders calls handler for each tar header provided by Unpacker
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func IterateHeaders(unpacker storage.Unpacker, handler func(hdr *tar.Header) error) error {
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// We assume about NewInputTarStream:
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// - There is a separate SegmentType entry for every tar header, but only one SegmentType entry for the full header incl. any extensions
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// - (There is a FileType entry for every tar header, we ignore it)
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// - Trailing padding of a file, if any, is included in the next SegmentType entry
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// - At the end, there may be SegmentType entries just for the terminating zero blocks.
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var pendingPadding int64 = 0
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for {
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tsEntry, err := unpacker.Next()
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if err != nil {
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if err == io.EOF {
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return nil
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}
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return fmt.Errorf("reading tar-split entries: %w", err)
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}
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switch tsEntry.Type {
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case storage.SegmentType:
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payload := tsEntry.Payload
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if int64(len(payload)) < pendingPadding {
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return fmt.Errorf("expected %d bytes of padding after previous file, but next SegmentType only has %d bytes", pendingPadding, len(payload))
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}
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payload = payload[pendingPadding:]
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pendingPadding = 0
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tr := tar.NewReader(bytes.NewReader(payload))
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hdr, err := tr.Next()
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if err != nil {
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if err == io.EOF { // Probably the last entry, but let’s let the unpacker drive that.
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break
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}
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return fmt.Errorf("decoding a tar header from a tar-split entry: %w", err)
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}
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if err := handler(hdr); err != nil {
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return err
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}
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pendingPadding = tr.ExpectedPadding()
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case storage.FileType:
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// Nothing
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default:
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return fmt.Errorf("unexpected tar-split entry type %q", tsEntry.Type)
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}
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}
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}
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