28 lines
641 B
Go
28 lines
641 B
Go
//go:build linux
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package httpdl
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import (
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"os"
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"golang.org/x/sys/unix"
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)
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// allocate reserves disk space for the output file according to the
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// --file-allocation mode: none does nothing (sparse), trunc sets the size,
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// prealloc/falloc reserve real blocks with fallocate (falling back to a plain
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// truncate if the filesystem does not support it).
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func allocate(f *os.File, mode string, size int64) error {
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switch mode {
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case "none":
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return nil
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case "trunc":
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return f.Truncate(size)
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default: // prealloc, falloc
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if err := unix.Fallocate(int(f.Fd()), 0, 0, size); err != nil {
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return f.Truncate(size)
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}
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return nil
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}
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}
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