IncludeFileSystem -> DefaultFileSystem (#677)

Improvements in 'singleton'ness of DefaultFileSystem
Made WrapFileSystem a stand alone type - to remove 'odd' aspects of deriving from DefaultFileSystem (such as inheriting getSingleton method/fixing ref counting)
Simplified CompileRequest::loadFile - becauce fileSystemExt is always available.

1 files changed, 93 insertions, 0 deletions

diff --git a/source/slang/default-file-system.h b/source/slang/default-file-system.h
new file mode 100644
index 000000000..62d7cbfc5
--- /dev/null
+++ b/source/slang/default-file-system.h
@@ -0,0 +1,93 @@
+#ifndef SLANG_DEFAULT_FILE_SYSTEM_H_INCLUDED
+#define SLANG_DEFAULT_FILE_SYSTEM_H_INCLUDED
+
+#include "../../slang.h"
+#include "../../slang-com-helper.h"
+#include "../../slang-com-ptr.h"
+
+namespace Slang
+{
+
+class DefaultFileSystem : public ISlangFileSystemExt
+{
+public:
+    // ISlangUnknown 
+    // override ref counting, as DefaultFileSystem is singleton
+    SLANG_IUNKNOWN_QUERY_INTERFACE 
+    SLANG_NO_THROW uint32_t SLANG_MCALL addRef() SLANG_OVERRIDE { return 1; }
+    SLANG_NO_THROW uint32_t SLANG_MCALL release() SLANG_OVERRIDE { return 1; } 
+
+    // ISlangFileSystem
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL loadFile(
+        char const*     path,
+        ISlangBlob**    outBlob) SLANG_OVERRIDE;
+
+    // ISlangFileSystemExt
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL getCanoncialPath(
+            const char* path,
+            ISlangBlob** canonicalPathOut) SLANG_OVERRIDE;
+
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL calcRelativePath(
+        SlangPathType fromPathType,
+        const char* fromPath,
+        const char* path,
+        ISlangBlob** pathOut) SLANG_OVERRIDE;
+
+        /// Get a default instance
+    static ISlangFileSystemExt* getSingleton() { return &s_singleton; }
+
+private:
+        /// Make so not constructable
+    DefaultFileSystem() {}
+
+    ISlangUnknown* getInterface(const Guid& guid);
+
+    static DefaultFileSystem s_singleton;
+};
+
+/* Wraps an ISlangFileSystem, and provides the extra methods required to make a ISlangFileSystemExt 
+interface, deferring to the contained file system to do reading. 
+
+NOTE! That this behavior is the same as previously in that.... 
+1) calcRelativePath, just returns the path as processed by the Path:: methods 
+2) getCanonicalPath, just returns the input path as the 'canonical' path. This will be wrong with a file multiply referenced through paths with .. and or . but 
+doing it this way means it works as before and requires no new functions.
+*/
+class WrapFileSystem : public ISlangFileSystemExt
+{
+public:
+    // ISlangUnknown 
+    SLANG_IUNKNOWN_ALL
+    
+    // ISlangFileSystem
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL loadFile(
+        char const*     path,
+        ISlangBlob**    outBlob) SLANG_OVERRIDE;
+
+    // ISlangFileSystemExt
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL getCanoncialPath(
+        const char* path,
+        ISlangBlob** canonicalPathOut) SLANG_OVERRIDE;
+
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL calcRelativePath(
+        SlangPathType fromPathType,
+        const char* fromPath,
+        const char* path,
+        ISlangBlob** pathOut) SLANG_OVERRIDE;
+
+        /// Ctor
+    WrapFileSystem(ISlangFileSystem* fileSystem):
+        m_fileSystem(fileSystem)
+    {
+    }
+
+protected:
+    ISlangUnknown* getInterface(const Guid& guid);
+
+    ComPtr<ISlangFileSystem> m_fileSystem;                  ///< The wrapped file system
+    uint32_t m_refCount = 0;
+};
+
+}
+
+#endif
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