🧱 Chunk is a download manager for slow and unstable servers
Merge pull request #11 from cuducos/calculate-chunks
Adds chunk struct and its generator
authored by
Eduardo Cuducos
and committed by
GitHub
b5ffd71f
beb5eee5
+52
+26
main.go
+26
main.go
···
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return b, nil
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}
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type chunk struct {
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start uint64
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end uint64
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}
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func (c chunk) size() uint64 { return (c.end + 1) - c.start }
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func (c chunk) rangeHeader() string { return fmt.Sprintf("bytes=%d-%d", c.start, c.end) }
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func (d *Downloader) chunks(t uint64) []chunk {
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var start uint64
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last := t - 1
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var c []chunk
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for {
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end := start + d.ChunkSize - 1
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if end > last {
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end = last
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}
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c = append(c, chunk{start, end})
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if end == last {
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break
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}
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start = end + 1
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}
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return c
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}
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// DownloadWithContext is a version of Download that takes a context. The
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// context can be used to stop all downloads in progress.
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func (d *Downloader) DownloadWithContext(ctx context.Context, urls ...string) <-chan DownloadStatus {
+26
main_test.go
+26
main_test.go
···
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t.Error("expected channel closed, but did not get it")
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}
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}
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func TestDownload_Chunks(t *testing.T) {
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d := DefaultDownloader()
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d.ChunkSize = 5
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got := d.chunks(12)
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chunks := []chunk{{0, 4}, {5, 9}, {10, 11}}
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sizes := []uint64{5, 5, 2}
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headers := []string{"bytes=0-4", "bytes=5-9", "bytes=10-11"}
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if len(got) != len(chunks) {
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t.Errorf("expected %d chunks, got %d", len(chunks), len(got))
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}
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for i := range got {
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if got[i].start != chunks[i].start {
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t.Errorf("expected chunk #%d to start at %d, got %d", i+1, chunks[i].start, got[i].start)
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}
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if got[i].end != chunks[i].end {
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t.Errorf("expected chunk #%d to end at %d, got %d", i+1, chunks[i].end, got[i].end)
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}
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if got[i].size() != sizes[i] {
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t.Errorf("expected chunk #%d to have size %d, got %d", i+1, sizes[i], got[i].size())
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}
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if got[i].rangeHeader() != headers[i] {
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t.Errorf("expected chunk #%d header to be %s, got %s", i+1, headers[i], got[i].rangeHeader())
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}
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}
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}