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Removed numbering on file naming and separated into separate sub-directories for getting-started, using, and contributing.
35 lines
1.6 KiB
Markdown
35 lines
1.6 KiB
Markdown
| [docs](..) / [using](.) / delta-packages.md
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# Delta Packages
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Now, once we've got a full package, we need to generate a Delta package. To do this, we'll replace all the DLL/EXEs in the NuGet packages with bsdiff files. [bspatch/bsdiff](http://code.logos.com/blog/2010/12/binary_patching_with_bsdiff.html) is a mostly efficient algorithm for calculating diffs between binary files (especially Native binaries, but it works well for .NET ones too), and a way to apply them.
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So, this is pretty easy:
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1. Extract the previous NuGet package
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1. Extract the current NuGet package
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1. Replace every EXE/DLL with the bsdiff. So, `lib\net40\MyCoolApp.exe` becomes `lib\net40\MyCoolApp.exe.diff`. Create a file that contains a SHA1 of the expected resulting file and its filesize called `lib\net40\MyCoolApp.exe.shasum`
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1. New DLLs in current get put in verbatim
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1. Zip it back up
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The .shasum file has the same format as the Releases file described in the "'Latest' Pointer" section, except that it will only have one entry.
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So now we've got all of the *metadata* of the original package, just none of its *contents*. To get the final package, we do the following:
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1. Take the previous version, expand it out
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1. Take the delta version, do the same
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1. For each DLL in the previous package, we bspatch it, then check the shasum file to ensure we created the correct resulting file
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1. If we find a DLL in the new package, just copy it over
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1. If we can't find a bspatch for a file, nuke it (it doesn't exist in the new rev)
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1. Zip it back up
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---
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| Return: [Table of Contents](../readme.md) |
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