devirtualises BSAFile (#3161)

Currently, Open MW's basic file access speed is limited by a peculiar layer of virtualisation in BSAFile's interface. This PR removes such virtualisation by properly separating BSAFile from CompressedBSAFile in low level contexts.

components/bsa/bsa_file.cpp

@@ -290,11 +290,6 @@ Files::IStreamPtr BSAFile::getFile(const char *file)
     return Files::openConstrainedFileStream (mFilename.c_str (), fs.offset, fs.fileSize);
 }
 
-Files::IStreamPtr BSAFile::getFile(const FileStruct *file)
-{
-    return Files::openConstrainedFileStream (mFilename.c_str (), file->offset, file->fileSize);
-}
-
 void Bsa::BSAFile::addFile(const std::string& filename, std::istream& file)
 {
     if (!mIsLoaded)

components/bsa/bsa_file.hpp

@@ -154,7 +154,10 @@ public:
     /** Open a file contained in the archive.
      * @note Thread safe.
     */
-    virtual Files::IStreamPtr getFile(const FileStruct* file);
+    Files::IStreamPtr getFile(const FileStruct *file)
+    {
+        return Files::openConstrainedFileStream (mFilename.c_str (), file->offset, file->fileSize);
+    }
 
     virtual void addFile(const std::string& filename, std::istream& file);
 

components/bsa/compressedbsafile.hpp

@@ -93,7 +93,7 @@ namespace Bsa
         void readHeader() override;
        
         Files::IStreamPtr getFile(const char* filePath) override;
-        Files::IStreamPtr getFile(const FileStruct* fileStruct) override;
+        Files::IStreamPtr getFile(const FileStruct* fileStruct);
         void addFile(const std::string& filename, std::istream& file) override;
     };
 }

components/vfs/bsaarchive.cpp

@@ -1,5 +1,5 @@
 #include "bsaarchive.hpp"
-#include <components/bsa/compressedbsafile.hpp>
+
 #include <memory>
 
 namespace VFS
@@ -7,15 +7,7 @@ namespace VFS
 
 BsaArchive::BsaArchive(const std::string &filename)
 {
-    Bsa::BsaVersion bsaVersion = Bsa::CompressedBSAFile::detectVersion(filename);
-
-    if (bsaVersion == Bsa::BSAVER_COMPRESSED) {
-        mFile = std::make_unique<Bsa::CompressedBSAFile>(Bsa::CompressedBSAFile());
-    }
-    else {
     mFile = std::make_unique<Bsa::BSAFile>(Bsa::BSAFile());
-    }
-
     mFile->open(filename);
 
     const Bsa::BSAFile::FileList &filelist = mFile->getList();
@@ -25,6 +17,10 @@ BsaArchive::BsaArchive(const std::string &filename)
     }
 }
 
+BsaArchive::BsaArchive()
+{
+}
+
 BsaArchive::~BsaArchive() {
 }
 
@@ -56,6 +52,31 @@ std::string BsaArchive::getDescription() const
     return std::string{"BSA: "} + mFile->getFilename();
 }
 
+CompressedBsaArchive::CompressedBsaArchive(const std::string &filename)
+    : BsaArchive()
+{
+    mFile = std::make_unique<Bsa::BSAFile>(Bsa::CompressedBSAFile());
+    mFile->open(filename);
+
+    const Bsa::BSAFile::FileList &filelist = mFile->getList();
+    for(Bsa::BSAFile::FileList::const_iterator it = filelist.begin();it != filelist.end();++it)
+    {
+        mResources.emplace_back(&*it, mFile.get());
+        mCompressedResources.emplace_back(&*it, static_cast<Bsa::CompressedBSAFile*>(mFile.get()));
+    }
+}
+
+void CompressedBsaArchive::listResources(std::map<std::string, File *> &out, char (*normalize_function)(char))
+{
+    for (std::vector<CompressedBsaArchiveFile>::iterator it = mCompressedResources.begin(); it != mCompressedResources.end(); ++it)
+    {
+        std::string ent = it->mInfo->name();
+        std::transform(ent.begin(), ent.end(), ent.begin(), normalize_function);
+
+        out[ent] = &*it;
+    }
+}
+
 // ------------------------------------------------------------------------------
 
 BsaArchiveFile::BsaArchiveFile(const Bsa::BSAFile::FileStruct *info, Bsa::BSAFile* bsa)
@@ -70,4 +91,16 @@ Files::IStreamPtr BsaArchiveFile::open()
     return mFile->getFile(mInfo);
 }
 
+CompressedBsaArchiveFile::CompressedBsaArchiveFile(const Bsa::BSAFile::FileStruct *info, Bsa::CompressedBSAFile* bsa)
+    : BsaArchiveFile(info, bsa)
+    , mCompressedFile(bsa)
+{
+
+}
+
+Files::IStreamPtr CompressedBsaArchiveFile::open()
+{
+    return mCompressedFile->getFile(mInfo);
+}
+
 }

components/vfs/bsaarchive.hpp

@@ -4,6 +4,7 @@
 #include "archive.hpp"
 
 #include <components/bsa/bsa_file.hpp>
+#include <components/bsa/compressedbsafile.hpp>
 
 namespace VFS
 {
@@ -18,19 +19,43 @@ namespace VFS
         Bsa::BSAFile* mFile;
     };
 
+    class CompressedBsaArchiveFile : public BsaArchiveFile
+    {
+    public:
+        CompressedBsaArchiveFile(const Bsa::BSAFile::FileStruct* info, Bsa::CompressedBSAFile* bsa);
+
+        Files::IStreamPtr open() override;
+        Bsa::CompressedBSAFile* mCompressedFile;
+    };
+
+
     class BsaArchive : public Archive
     {
     public:
         BsaArchive(const std::string& filename);
+        BsaArchive();
         virtual ~BsaArchive();
         void listResources(std::map<std::string, File*>& out, char (*normalize_function) (char)) override;
         bool contains(const std::string& file, char (*normalize_function) (char)) const override;
         std::string getDescription() const override;
 
-    private:
+    protected:
         std::unique_ptr<Bsa::BSAFile> mFile;
         std::vector<BsaArchiveFile> mResources;
     };
+
+    class CompressedBsaArchive : public BsaArchive
+    {
+    public:
+        CompressedBsaArchive(const std::string& filename);
+        void listResources(std::map<std::string, File*>& out, char (*normalize_function) (char)) override;
+        virtual ~CompressedBsaArchive() {}
+
+    private:
+        std::unique_ptr<Bsa::CompressedBSAFile> mCompressedFile;
+        std::vector<CompressedBsaArchiveFile> mCompressedResources;
+    };
+
 }
 
 #endif

components/vfs/registerarchives.cpp

@@ -23,7 +23,11 @@ namespace VFS
                 // Last BSA has the highest priority
                 const std::string archivePath = collections.getPath(*archive).string();
                 Log(Debug::Info) << "Adding BSA archive " << archivePath;
+                Bsa::BsaVersion bsaVersion = Bsa::CompressedBSAFile::detectVersion(archivePath);
 
+                if (bsaVersion == Bsa::BSAVER_COMPRESSED)
+                    vfs->addArchive(new CompressedBsaArchive(archivePath));
+                else
                     vfs->addArchive(new BsaArchive(archivePath));
             }
             else