Review Request 122678: [WIP] KoResource and Krita bundles MD5 generation fix

Stefano Bonicatti smjert at gmail.com
Wed Jul 29 19:20:07 BST 2015 

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https://git.reviewboard.kde.org/r/122678/
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(Updated July 29, 2015, 6:20 p.m.)


Review request for Calligra.


Changes
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This patch fixes the issue of the bundles by outsourcing the md5 generation to a provider class and by using an abstract class (KoHashGenerator) that is inherited by KoMD5Generator to generate the hash in all those situations where a bundle (krita only thing) is not present. For Krita instead we have KisMD5Generator. 
This works because we can set through the provider a generator for a specific algorithm (currently they are recognized through all capital strings), substituting the default one.


Repository: calligra


Description
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Why is needed:

The hash of a resource is sometimes calculated on the file, sometimes on the interpreted (loaded) data which can vary between users or due to approximations, resulting in the md5 inside the bundle
to be different from the recalculated one.


What it does:

The md5 will be always calculated on the file and not on the interpreted data.
    
KoResource::generateMD5 is not pure virtual anymore, because all the resources has to share the same md5 generation.
    
KoResource::saveToDevice is not pure virtual anymore, because we need to set the md5 to empty each time the resource is saved, so that the next access to the md5 forces a recalculation.

KoResource::saveToDevice must be called from the saveToDevice functions of the inheriting classes.
    
saveResourceToStore has been modified so that it doesn't try to save a resource when a copy cannot be done, when creating a bundle.
Also if the file is writable it should be still copied.


What still needs to be done:

Unfortunately i discovered too late that this fixes only a small portion of issues, simply because when trying to generate a md5 from a file in a bundle, that filename or filepath isn't one that points to an existing file on the disk, but it's a path that has to be interpreted and the bundle has to be opened.
The idea to fix this is to override the generateMD5 function of all the bundle resource types and have special code to deal with the path (like KisPaintOpPreset::load function does), so that a temporary resource store is created to read the bundle file, otherwise just call KoResource::generateMD5(). 
The problem is that there are resource types as KoColorSet which i'm not completely sure they should know anything about bundles.

Even with that fixed there are resource types that cannot go into a bundle, but where i still removed their generateMD5 implementation, so that the base KoResource implementation is used. These needs to be tested, to see if i didn't introduce a regression.

This commit 8a19e6a469ebe784b038b802c346a80fdbd89b0d conflicts with my patch and the above reasoning, because it simply prevent bundle files md5 to be generated.

I've changed a bit how saveToDevice works, so that it empties the resource md5 everytime it's saved. This needs to be tested (if the md5, when acquired, is regenerated) and it should be checked if every possible resource has the call to KoResource::saveToDevice, otherwise it should be added.


Diffs (updated)
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  krita/image/brushengine/kis_paintop_preset.h 52caacc 
  krita/image/brushengine/kis_paintop_preset.cpp 736699d 
  krita/libbrush/kis_abr_brush.cpp ad717d4 
  krita/libbrush/kis_abr_brush_collection.cpp 554865b 
  krita/libbrush/kis_auto_brush.h c537697 
  krita/libbrush/kis_auto_brush.cpp 86cc379 
  krita/libbrush/kis_brush.h 1a1bf5c 
  krita/libbrush/kis_brush.cpp ea389ee 
  krita/libbrush/kis_gbr_brush.cpp 37158f9 
  krita/libbrush/kis_imagepipe_brush.cpp 4d301cb 
  krita/libbrush/kis_png_brush.cpp 358f8da 
  krita/libbrush/kis_svg_brush.cpp 2934a36 
  krita/plugins/extensions/dockers/tasksetdocker/taskset_resource.h 57ad287 
  krita/plugins/extensions/dockers/tasksetdocker/taskset_resource.cpp 6afc96f 
  krita/plugins/extensions/resourcemanager/resourcebundle.h 7e3c8b9 
  krita/plugins/extensions/resourcemanager/resourcebundle.cpp ba535d3 
  krita/ui/CMakeLists.txt 195d9b5 
  krita/ui/kis_factory2.cc 6e2fd9d 
  krita/ui/kis_md5_generator.h PRE-CREATION 
  krita/ui/kis_md5_generator.cpp PRE-CREATION 
  krita/ui/kis_workspace_resource.h aefc57c 
  krita/ui/kis_workspace_resource.cpp b71dc49 
  libs/pigment/CMakeLists.txt 4f54815 
  libs/pigment/resources/KoAbstractGradient.h 167be69 
  libs/pigment/resources/KoAbstractGradient.cpp 800a490 
  libs/pigment/resources/KoColorSet.h ffd81b8 
  libs/pigment/resources/KoColorSet.cpp 47d3c6b 
  libs/pigment/resources/KoHashGenerator.h PRE-CREATION 
  libs/pigment/resources/KoHashGeneratorProvider.h PRE-CREATION 
  libs/pigment/resources/KoHashGeneratorProvider.cpp PRE-CREATION 
  libs/pigment/resources/KoMD5Generator.h PRE-CREATION 
  libs/pigment/resources/KoMD5Generator.cpp PRE-CREATION 
  libs/pigment/resources/KoPattern.h 31acba4 
  libs/pigment/resources/KoPattern.cpp 1c1f521 
  libs/pigment/resources/KoResource.h 53a18e2 
  libs/pigment/resources/KoResource.cpp 2b568bf 
  libs/pigment/resources/KoSegmentGradient.h bdd6baa 
  libs/pigment/resources/KoSegmentGradient.cpp 5387743 
  libs/pigment/resources/KoStopGradient.h 2e1e3d4 
  libs/pigment/resources/KoStopGradient.cpp dc851da 

Diff: https://git.reviewboard.kde.org/r/122678/diff/


Testing
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Compiles.
The md5 inside the bundle manifests are correct, even for gradients (where normally the wrong one was used, since they're interpreted).


Thanks,

Stefano Bonicatti

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