Feature/include refactor (#675)

* Refactor of path handling.
* Added PathInfo
* Changed ISlangFileSystem - such that has separate concepts of reading a file, getting a relative path and getting a canonical path
* Added support for getting a canonical path for windows/linux
* Made maps/testing around canonicalPaths
* User output remains around 'foundPath' - which is the same as before

* Small improvements around PathInfo
* Added a type and make constructors to make clear the different 'path' uses
* Fixed bug in findViewRecursively

* Checking and reporting for ignored #pragma once.

* Removed SLANG_PATH_TYPE_NONE as doesn't serve any useful purpose.

* Improve comments in slang.h aroung ISlangFileSystem

* Remove the need for <windows.h> in slang-io.cpp

* Ran premake5.

* Improvements and fixes around PathInfo.

* Fix typo on linix GetCanonical

* Make the ISlangFileSystem the same as before, and ISlangFileSystem contain the new methods.
Internally it always uses the ISlangFileSystemExt, and will wrap a ISlangFileSystem with WrapFileSystem, if it is determined (via queryInterface) that it doesn't implement the full interface.

1 files changed, 7 insertions, 12 deletions

diff --git a/source/slang/preprocessor.h b/source/slang/preprocessor.h
index 0e30038bf..42a3b25f4 100644
--- a/source/slang/preprocessor.h
+++ b/source/slang/preprocessor.h
@@ -11,22 +11,17 @@ class DiagnosticSink;
 class ModuleDecl;
 class TranslationUnitRequest;
 
-enum class IncludeResult
-{
-    Error,
-    NotFound,
-    Found,
-};
-
 // Callback interface for the preprocessor to use when looking
 // for files in `#include` directives.
 struct IncludeHandler
 {
-    virtual IncludeResult TryToFindIncludeFile(
-        String const& pathToInclude,
-        String const& pathIncludedFrom,
-        String* outFoundPath,
-        ISlangBlob** outFoundSourceBlob) = 0;
+    
+    virtual SlangResult findFile(const String& pathToInclude,
+        const String& pathIncludedFrom,
+        PathInfo& pathInfoOut) = 0;
+
+    virtual SlangResult readFile(const String& path, 
+        ISlangBlob** blobOut) = 0;        
 };
 
 // Take a string of source code and preprocess it into a list of tokens.