34 lines
929 B
Text
34 lines
929 B
Text
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module Model
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open System
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open System.IO
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open System.Security.Cryptography
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type Outcome =
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| Cached
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| Installed
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let private checksum path =
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use input = File.OpenRead path
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SHA256.HashData input |> Convert.ToHexString |> _.ToLowerInvariant()
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let install expected destination (download: Stream -> unit) =
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if File.Exists destination && checksum destination = expected then
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Cached
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else
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Directory.CreateDirectory(Path.GetDirectoryName destination) |> ignore
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let temporary = destination + ".incoming"
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try
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do
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use output = File.Create temporary
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download output
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if checksum temporary <> expected then
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invalidOp "model checksum differs"
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File.Move(temporary, destination, true)
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Installed
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finally
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if File.Exists temporary then
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File.Delete temporary
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