* Added Path::combineBuilder, so as two sub paths can be combined into a StringBuilder (#988)

* Renamed and improved comments on SharedLibrary

5 files changed, 70 insertions, 26 deletions

diff --git a/source/core/slang-io.cpp b/source/core/slang-io.cpp
index 83f21d5dd..01c8b38e0 100644
--- a/source/core/slang-io.cpp
+++ b/source/core/slang-io.cpp
@@ -137,13 +137,40 @@ namespace Slang
 	String Path::combine(const String& path1, const String& path2)
 	{
 		if (path1.getLength() == 0) return path2;
-		StringBuilder sb(path1.getLength()+path2.getLength()+2);
-		sb.Append(path1);
-		if (!path1.endsWith('\\') && !path1.endsWith('/'))
-			sb.Append(kPathDelimiter);
-		sb.Append(path2);
-		return sb.ProduceString();
+
+        StringBuilder sb;
+        combineBuilder(path1.getUnownedSlice(), path2.getUnownedSlice(), sb);
+        return sb.ProduceString();
 	}
+    /* static */void Path::combineBuilder(const UnownedStringSlice& path1, const UnownedStringSlice& path2, StringBuilder& outBuilder)
+    {
+        outBuilder.Clear();
+        // Make sure we have the space for the full result
+        outBuilder.EnsureCapacity(path1.size() + 2 + path2.size());
+
+        if (path1.size() == 0)
+        {
+            outBuilder.append(path2);
+            return;
+        }
+
+        outBuilder.append(path1);
+
+        // If path1 doesn't end in a delimiter, add one
+        if (!isDelimiter(path1[path1.size() - 1]))
+        {
+            outBuilder.append(kPathDelimiter);
+        }
+
+        // Check that path2 doesn't start with a path delimiter 
+        if (path2.size() > 0)
+        {
+            SLANG_ASSERT(!isDelimiter(path2[0]));
+        }
+        // Append the second path
+        outBuilder.append(path2);
+    }
+
 	String Path::combine(const String& path1, const String& path2, const String& path3)
 	{
 		StringBuilder sb(path1.getLength()+path2.getLength()+path3.getLength()+3);
diff --git a/source/core/slang-io.h b/source/core/slang-io.h
index 4fa921662..91cfaf290 100644
--- a/source/core/slang-io.h
+++ b/source/core/slang-io.h
@@ -29,8 +29,13 @@ namespace Slang
 		static String getFileNameWithoutExt(const String& path);
 		static String getFileExt(const String& path);
 		static String getParentDirectory(const String& path);
+
 		static String combine(const String& path1, const String& path2);
 		static String combine(const String& path1, const String& path2, const String& path3);
+
+            /// Combine path sections and store the result in outBuilder
+        static void combineBuilder(const UnownedStringSlice& path1, const UnownedStringSlice& path2, StringBuilder& outBuilder);
+
 		static bool createDirectory(const String& path);
 
             /// Accept either style of delimiter
diff --git a/source/core/slang-platform.cpp b/source/core/slang-platform.cpp
index 82f914f7d..8055d3e55 100644
--- a/source/core/slang-platform.cpp
+++ b/source/core/slang-platform.cpp
@@ -19,32 +19,40 @@ namespace Slang
 {
 	// SharedLibrary
 
-/* static */SlangResult SharedLibrary::load(const char* filename, SharedLibrary::Handle& handleOut)
+/* static */SlangResult SharedLibrary::load(const char* path, SharedLibrary::Handle& handleOut)
 {
     StringBuilder builder;
-    appendPlatformFileName(UnownedStringSlice(filename), builder);
-    return loadWithPlatformFilename(builder.begin(), handleOut);
+    calcPlatformPath(UnownedStringSlice(path), builder);
+    return loadWithPlatformPath(builder.begin(), handleOut);
 }
 
-/* static */String SharedLibrary::calcPlatformPath(const UnownedStringSlice& path)
+/* static */void SharedLibrary::calcPlatformPath(const UnownedStringSlice& path, StringBuilder& outPath)
 {
     // Work out the shared library name
     String parent = Path::getParentDirectory(path);
     String filename = Path::getFileName(path);
-    
-    StringBuilder builder;
-    SharedLibrary::appendPlatformFileName(filename.getUnownedSlice(), builder);
 
     if (parent.getLength() > 0)
     {
-        return Path::combine(parent, builder);
+        // Work out the filename platform name (as in add .dll say on windows)
+        StringBuilder platformFileNameBuilder;
+        SharedLibrary::appendPlatformFileName(filename.getUnownedSlice(), platformFileNameBuilder);
+
+        Path::combineBuilder(parent.getUnownedSlice(), platformFileNameBuilder.getUnownedSlice(), outPath);
     }
     else
-    {
-        return builder;
+    {     
+        appendPlatformFileName(filename.getUnownedSlice(), outPath);
     }
 }
 
+/* static */String SharedLibrary::calcPlatformPath(const UnownedStringSlice& path)
+{
+    StringBuilder builder;
+    calcPlatformPath(path, builder);
+    return builder.ToString();
+}
+
 #ifdef _WIN32
 
 // Make sure SlangResult match for common standard window HRESULT
@@ -80,7 +88,7 @@ SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);
     return SLANG_FAIL;
 }
 
-/* static */SlangResult SharedLibrary::loadWithPlatformFilename(char const* platformFileName, SharedLibrary::Handle& handleOut)
+/* static */SlangResult SharedLibrary::loadWithPlatformPath(char const* platformFileName, SharedLibrary::Handle& handleOut)
 {
     handleOut = nullptr;
     // https://docs.microsoft.com/en-us/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibrarya
@@ -136,7 +144,7 @@ SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);
     return SLANG_E_NOT_IMPLEMENTED;
 }
 
-/* static */SlangResult SharedLibrary::loadWithPlatformFilename(char const* platformFileName, Handle& handleOut)
+/* static */SlangResult SharedLibrary::loadWithPlatformPath(char const* platformFileName, Handle& handleOut)
 {
     handleOut = nullptr;
 
diff --git a/source/core/slang-platform.h b/source/core/slang-platform.h
index c322d0568..0e6d12cb6 100644
--- a/source/core/slang-platform.h
+++ b/source/core/slang-platform.h
@@ -15,24 +15,27 @@ namespace Slang
         
         typedef void(*FuncPtr)(void);
 
-            /// Load via an unadorned filename.
+            /// Load via an unadorned path/filename.
             ///
-            /// The unadorned filename here means without any platform specific filename elements. This typically means no extension and no prefix.
+            /// The unadorned path here means without a path without any platform specific filename elements.
+            /// This typically means no extension and no prefix.
             /// On windows this means without the '.dll' extension.
             /// On linux this means without the 'lib' prefix and '.so' extension.
             /// To load with a platform specific filename use the 'loadWithPlatformFilename' API
+            /// Most platforms have a built in mechanism to search for shared libraries, such that
+            /// shared libraries are often just passed by filename.
             /// 
-            /// @param the unadorned filename
+            /// @param the unadorned filename/path
             /// @return Returns a non null handle for the shared library on success. nullptr indicated failure
-        static SlangResult load(const char* filename, Handle& handleOut);
+        static SlangResult load(const char* path, Handle& handleOut);
 
 		    /// Attempt to load a shared library for
 		    /// the current platform. Returns null handle on failure
             /// The platform specific filename can be generated from a call to appendPlatformFileName
             ///
-            /// @param platformFileName the platform specific file name. 
+            /// @param platform the platform specific file name/ or path 
             /// @return Returns a non null handle for the shared library on success. nullptr indicated failure
-        static SlangResult loadWithPlatformFilename(char const* platformFileName, Handle& handleOut);
+        static SlangResult loadWithPlatformPath(char const* platformPath, Handle& handleOut);
 
             /// Unload the library that was returned from load as handle
             /// @param The valid handle returned from load 
@@ -49,6 +52,7 @@ namespace Slang
 
             /// Given a path, calculate that path with the filename replaced with the platform filename (using appendPlatformFilename)
         static String calcPlatformPath(const UnownedStringSlice& path);
+        static void calcPlatformPath(const UnownedStringSlice& path, StringBuilder& outBuilder);
 
         private:
             /// Not constructible!
diff --git a/source/core/slang-shared-library.cpp b/source/core/slang-shared-library.cpp
index 009abf921..9932db0b5 100644
--- a/source/core/slang-shared-library.cpp
+++ b/source/core/slang-shared-library.cpp
@@ -99,7 +99,7 @@ SlangResult ConfigurableSharedLibraryLoader::loadSharedLibrary(const char* path,
 {
     SLANG_UNUSED(pathIn);
     // The replacement is the *whole* string
-    return SharedLibrary::loadWithPlatformFilename(entryString.begin(), handleOut);
+    return SharedLibrary::loadWithPlatformPath(entryString.begin(), handleOut);
 }
 
 /* static */Result ConfigurableSharedLibraryLoader::changePath(const char* pathIn, const String& entryString, SharedLibrary::Handle& handleOut )
@@ -109,7 +109,7 @@ SlangResult ConfigurableSharedLibraryLoader::loadSharedLibrary(const char* path,
     SharedLibrary::appendPlatformFileName(UnownedStringSlice(pathIn), builder);
     String path = Path::combine(entryString, builder);
 
-    return SharedLibrary::loadWithPlatformFilename(path.begin(), handleOut);
+    return SharedLibrary::loadWithPlatformPath(path.begin(), handleOut);
 }