A more convoluted #pragma once file identity test, using relative paths. (#1021)

* A more convoluted #pragma once file identity test, using relative paths.

* Fix bug with passing - to slang as a command line option causes a crash.
Ability to set file-system to use on command line.
#pragma once tests try with 'normal' and 'read-file' only versions

* OSFileSystem -> OSFileSystemExt
LoadFileOSFileSystem -> OSFileSystem

Implemented OSFileSystem like OSFileSystemExt as as singleton.
Fixes to comments.

9 files changed, 116 insertions, 18 deletions

diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index 802c89f8b..c1c207fd7 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -69,6 +69,8 @@ DIAGNOSTIC(    14, Error, unknownProfile, "unknown profile '$0'");
 DIAGNOSTIC(    15, Error, unknownStage, "unknown stage '$0'");
 DIAGNOSTIC(    16, Error, unknownPassThroughTarget, "unknown pass-through target '$0'");
 DIAGNOSTIC(    17, Error, unknownCommandLineOption, "unknown command-line option '$0'");
+DIAGNOSTIC(    18, Error, unknownFileSystemOption, "unknown file-system option '$0'");
+
 DIAGNOSTIC(    20, Error, entryPointsNeedToBeAssociatedWithTranslationUnits, "when using multiple source files, entry points must be specified after their corresponding source file(s)");
 DIAGNOSTIC(    21, Error, expectedArgumentForOption, "expected an argument for command-line option '$0'");
 
diff --git a/source/slang/slang-file-system.cpp b/source/slang/slang-file-system.cpp
index f8c423e84..975d35f2c 100644
--- a/source/slang/slang-file-system.cpp
+++ b/source/slang/slang-file-system.cpp
@@ -36,9 +36,18 @@ static SlangResult _calcCombinedPath(SlangPathType fromPathType, const char* fro
     return SLANG_OK;
 }
 
-/* !!!!!!!!!!!!!!!!!!!!!!!!!! IncludeFileSystem !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+/* !!!!!!!!!!!!!!!!!!!!!!!!!!!!! OSFileSystem !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
 
-/* static */OSFileSystem OSFileSystem::s_singleton; 
+/* static */OSFileSystem OSFileSystem::s_singleton;
+
+ISlangUnknown* OSFileSystem::getInterface(const Guid& guid)
+{
+    return (guid == IID_ISlangUnknown || guid == IID_ISlangFileSystem ) ? static_cast<ISlangFileSystem*>(this) : nullptr;
+}
+
+/* !!!!!!!!!!!!!!!!!!!!!!!!!! OSFileSystemExt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*/
+
+/* static */OSFileSystemExt OSFileSystemExt::s_singleton; 
 
 template <typename T>
 static ISlangFileSystemExt* _getInterface(T* ptr, const Guid& guid)
@@ -46,7 +55,7 @@ static ISlangFileSystemExt* _getInterface(T* ptr, const Guid& guid)
     return (guid == IID_ISlangUnknown || guid == IID_ISlangFileSystem || guid == IID_ISlangFileSystemExt) ? static_cast<ISlangFileSystemExt*>(ptr) : nullptr;
 }
 
-ISlangUnknown* OSFileSystem::getInterface(const Guid& guid)
+ISlangUnknown* OSFileSystemExt::getInterface(const Guid& guid)
 {
     return _getInterface(this, guid); 
 }
@@ -62,13 +71,13 @@ static String _fixPathDelimiters(const char* pathIn)
 #endif
 }
 
-SlangResult OSFileSystem::getFileUniqueIdentity(const char* pathIn, ISlangBlob** outUniqueIdentity)
+SlangResult OSFileSystemExt::getFileUniqueIdentity(const char* pathIn, ISlangBlob** outUniqueIdentity)
 {
     // By default we use the canonical path to uniquely identify a file
     return getCanonicalPath(pathIn, outUniqueIdentity);
 }
 
-SlangResult OSFileSystem::getCanonicalPath(const char* path, ISlangBlob** outCanonicalPath)
+SlangResult OSFileSystemExt::getCanonicalPath(const char* path, ISlangBlob** outCanonicalPath)
 {
     String canonicalPath;
     SLANG_RETURN_ON_FAIL(Path::getCanonical(_fixPathDelimiters(path), canonicalPath));
@@ -76,25 +85,25 @@ SlangResult OSFileSystem::getCanonicalPath(const char* path, ISlangBlob** outCan
     return SLANG_OK;
 }
 
-SlangResult OSFileSystem::getSimplifiedPath(const char* pathIn, ISlangBlob** outSimplifiedPath)
+SlangResult OSFileSystemExt::getSimplifiedPath(const char* pathIn, ISlangBlob** outSimplifiedPath)
 {
     String simplifiedPath = Path::simplify(_fixPathDelimiters(pathIn));
     *outSimplifiedPath = StringUtil::createStringBlob(simplifiedPath).detach();
     return SLANG_OK;
 }
 
-SlangResult OSFileSystem::calcCombinedPath(SlangPathType fromPathType, const char* fromPath, const char* path, ISlangBlob** pathOut)
+SlangResult OSFileSystemExt::calcCombinedPath(SlangPathType fromPathType, const char* fromPath, const char* path, ISlangBlob** pathOut)
 {
     // Don't need to fix delimiters - because combine path handles both path delimiter types
     return _calcCombinedPath(fromPathType, fromPath, path, pathOut);
 }
 
-SlangResult SLANG_MCALL OSFileSystem::getPathType(const char* pathIn, SlangPathType* pathTypeOut)
+SlangResult SLANG_MCALL OSFileSystemExt::getPathType(const char* pathIn, SlangPathType* pathTypeOut)
 {
     return Path::getPathType(_fixPathDelimiters(pathIn), pathTypeOut);
 }
 
-SlangResult OSFileSystem::loadFile(char const* pathIn, ISlangBlob** outBlob)
+SlangResult OSFileSystemExt::loadFile(char const* pathIn, ISlangBlob** outBlob)
 {
     // Default implementation that uses the `core` libraries facilities for talking to the OS filesystem.
     //
diff --git a/source/slang/slang-file-system.h b/source/slang/slang-file-system.h
index 1d747d73f..d91d8ff65 100644
--- a/source/slang/slang-file-system.h
+++ b/source/slang/slang-file-system.h
@@ -11,7 +11,8 @@
 namespace Slang
 {
 
-class OSFileSystem : public ISlangFileSystemExt
+// Implementation of ISlangFileSystemExt for the OS
+class OSFileSystemExt : public ISlangFileSystemExt
 {
 public:
     // ISlangUnknown 
@@ -55,11 +56,40 @@ public:
 
 private:
         /// Make so not constructible
-    OSFileSystem() {}
-    virtual ~OSFileSystem() {}
+    OSFileSystemExt() {}
+    virtual ~OSFileSystemExt() {}
 
     ISlangUnknown* getInterface(const Guid& guid);
 
+    static OSFileSystemExt s_singleton;
+};
+
+// Implementation of ISlangFileSystem for the OS (ie only has simplified interface of just loadFile)
+class OSFileSystem : public ISlangFileSystem
+{
+public:
+        // ISlangUnknown 
+    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
+    {
+        // Can just use OsFileSystemExt impl
+        return OSFileSystemExt::getSingleton()->loadFile(path, outBlob);
+    }
+
+     static ISlangFileSystem* getSingleton() { return &s_singleton; }
+
+private:
+    /// Make so not constructible
+        OSFileSystem() {}
+    virtual ~OSFileSystem() {}
+
+    ISlangUnknown* getInterface(const Guid& guid);
     static OSFileSystem s_singleton;
 };
 
diff --git a/source/slang/slang-options.cpp b/source/slang/slang-options.cpp
index 81fb468eb..5918f1551 100644
--- a/source/slang/slang-options.cpp
+++ b/source/slang/slang-options.cpp
@@ -8,6 +8,8 @@
 #include "slang-compiler.h"
 #include "slang-profile.h"
 
+#include "slang-file-system.h"
+
 #include <assert.h>
 
 namespace Slang {
@@ -632,7 +634,7 @@ struct OptionsParser
                     SLANG_RETURN_ON_FAIL(tryReadCommandLineArgument(sink, arg, &argCursor, argEnd, name));
                     addSharedLibraryPath(SharedLibraryType::Fxc, name);
                 }
-                else if (argStr[1] == 'D')
+                else if (argStr.getLength() >= 2 && argStr[1] == 'D')
                 {
                     // The value to be defined might be part of the same option, as in:
                     //     -DFOO
@@ -677,7 +679,7 @@ struct OptionsParser
                             "");
                     }
                 }
-                else if (argStr[1] == 'I')
+                else if (argStr.getLength() >= 2 && argStr[1] == 'I')
                 {
                     // The value to be defined might be part of the same option, as in:
                     //     -IFOO
@@ -803,6 +805,25 @@ struct OptionsParser
                 {
                     requestImpl->getBackEndReq()->useUnknownImageFormatAsDefault = true;
                 }
+                else if (argStr == "-file-system")
+                {
+                    String name;
+                    SLANG_RETURN_ON_FAIL(tryReadCommandLineArgument(sink, arg, &argCursor, argEnd, name));
+
+                    if (name == "default")
+                    {
+                        spSetFileSystem(compileRequest, nullptr);
+                    }
+                    else if (name == "load-file")
+                    {
+                        spSetFileSystem(compileRequest, OSFileSystem::getSingleton());
+                    }
+                    else
+                    {
+                        sink->diagnose(SourceLoc(), Diagnostics::unknownFileSystemOption, name);
+                        return SLANG_FAIL;
+                    }
+                }
                 else if (argStr == "--")
                 {
                     // The `--` option causes us to stop trying to parse options,
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index f0570132f..eef0dff6f 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -2365,17 +2365,17 @@ void Linkage::setFileSystem(ISlangFileSystem* inFileSystem)
     // Set the fileSystem
     fileSystem = inFileSystem;
 
-    // Set up fileSystemExt appropriately
+    // If nullptr passed in set up default 
     if (inFileSystem == nullptr)
     {
-        fileSystemExt = new Slang::CacheFileSystem(Slang::OSFileSystem::getSingleton());
+        fileSystemExt = new Slang::CacheFileSystem(Slang::OSFileSystemExt::getSingleton());
     }
     else
     {
-        // See if we have the interface 
+        // See if we have the full ISlangFileSystemExt interface, if we do just use it
         inFileSystem->queryInterface(IID_ISlangFileSystemExt, (void**)fileSystemExt.writeRef());
 
-        // If not wrap with WrapFileSytem that keeps the old behavior
+        // If not wrap with CacheFileSystem that emulates ISlangFileSystemExt from the ISlangFileSystem interface
         if (!fileSystemExt)
         {
             // Construct a wrapper to emulate the extended interface behavior
diff --git a/tests/preprocessor/file-identity/b.h b/tests/preprocessor/file-identity/b.h
new file mode 100644
index 000000000..ba131c653
--- /dev/null
+++ b/tests/preprocessor/file-identity/b.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "c.h"
+
+#ifdef B_H
+#   error "Shouldn't be included twice"
+#endif
+
+#define B_H
+
+float foo(float x) { return x; }
\ No newline at end of file
diff --git a/tests/preprocessor/file-identity/c.h b/tests/preprocessor/file-identity/c.h
new file mode 100644
index 000000000..eb6cd1c42
--- /dev/null
+++ b/tests/preprocessor/file-identity/c.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "b.h"
+
+#ifdef C_H
+#   error "c.h shouldn't be included twice"
+#endif
+
+#define C_H
+
+float bar(float x) { return x; }
\ No newline at end of file
diff --git a/tests/preprocessor/file-identity/sub-folder/file-identity.slang b/tests/preprocessor/file-identity/sub-folder/file-identity.slang
new file mode 100644
index 000000000..590b32a70
--- /dev/null
+++ b/tests/preprocessor/file-identity/sub-folder/file-identity.slang
@@ -0,0 +1,13 @@
+//TEST(smoke):SIMPLE:
+//TEST(smoke):SIMPLE: -file-system load-file
+
+
+#include "../b.h"
+#include "../c.h"
+
+#include "./../b.h"
+
+float test(float x)
+{
+	return foo(x) + bar(x);
+}
\ No newline at end of file
diff --git a/tests/preprocessor/pragma-once.slang b/tests/preprocessor/pragma-once.slang
index 43ddee680..ef43ea265 100644
--- a/tests/preprocessor/pragma-once.slang
+++ b/tests/preprocessor/pragma-once.slang
@@ -1,4 +1,5 @@
 //TEST(smoke):SIMPLE:
+//TEST(smoke):SIMPLE: -file-system load-file
 
 // Test support for `#pragma once`