35 lines
1.0 KiB
C#
35 lines
1.0 KiB
C#
 
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using System.Runtime.InteropServices;
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namespace PrivaPub.Infrastructure.Backup
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{
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// A second name for a file (.NET has no API for it): a backup links the live media, which costs no disk, since names are
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// random and files never change; deleting the live one leaves the backup's.
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static class HardLink
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{
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// strings go to libc as UTF-8 on Unix
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[DllImport("libc", EntryPoint = "link", SetLastError = true, CharSet = CharSet.Ansi)]
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static extern int Link(string existing, string created);
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/// <summary>Links, or copies where a link can't be made (another disk, a filesystem refusing it).</summary>
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public static bool LinkOrCopy(string existing, string created)
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{
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Directory.CreateDirectory(Path.GetDirectoryName(created)!);
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if (OperatingSystem.IsLinux())
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{
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try
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{
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if (Link(existing, created) == 0)
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return true;
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}
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catch (DllNotFoundException)
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{
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}
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catch (EntryPointNotFoundException)
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{
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}
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}
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File.Copy(existing, created, overwrite: true);
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return false;
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}
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}
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}
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