Disable default file handler and Add hook so external projects can ho…

…ok their own internal file handling objects
Mojang · Jun 29, 2021 · e1cff96 · e1cff96
1 parent 2ab7f96
commit e1cff96
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Showing 4 changed files with 86 additions and 3 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -0,0 +1,21 @@
+# USE_NATIVE_IMGUI_INCLUDE_PATHS is set to true by default include direct path to imgui headers
+# User can set it to false to create a custom way of including imgui to their project
+option(USE_NATIVE_IMGUI_INCLUDE_PATHS "Set this to false if you want to define your own target_include_directories function for imgui." true)
+
+add_library(imgui STATIC)
+
+target_sources(imgui
+PRIVATE
+  imgui.h
+  imconfig.h
+  imgui_demo.cpp
+  imgui_draw.cpp
+  imgui_internal.h
+  imgui_widgets.cpp
+  imgui.cpp
+  imgui_tables.cpp
+)
+
+if(USE_NATIVE_IMGUI_INCLUDE_PATHS)
+  target_include_directories(imgui PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+endif()
diff --git a/imconfig.h b/imconfig.h
@@ -43,7 +43,7 @@
 //#define IMGUI_DISABLE_DEFAULT_FORMAT_FUNCTIONS            // Don't implement ImFormatString/ImFormatStringV so you can implement them yourself (e.g. if you don't want to link with vsnprintf)
 //#define IMGUI_DISABLE_DEFAULT_MATH_FUNCTIONS              // Don't implement ImFabs/ImSqrt/ImPow/ImFmod/ImCos/ImSin/ImAcos/ImAtan2 so you can implement them yourself.
 //#define IMGUI_DISABLE_FILE_FUNCTIONS                      // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite and ImFileHandle at all (replace them with dummies)
-//#define IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS              // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite and ImFileHandle so you can implement them yourself if you don't want to link with fopen/fclose/fread/fwrite. This will also disable the LogToTTY() function.
+#define IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS              // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite so you can implement them yourself if you don't want to link with fopen/fclose/fread/fwrite. This will also disable the LogToTTY() function.
 //#define IMGUI_DISABLE_DEFAULT_ALLOCATORS                  // Don't implement default allocators calling malloc()/free() to avoid linking with them. You will need to call ImGui::SetAllocatorFunctions().
 //#define IMGUI_DISABLE_SSE                                 // Disable use of SSE intrinsics even if available
 

diff --git a/imgui.cpp b/imgui.cpp
@@ -1565,7 +1565,49 @@ bool    ImFileClose(ImFileHandle f)     { return fclose(f) == 0; }
 ImU64   ImFileGetSize(ImFileHandle f)   { long off = 0, sz = 0; return ((off = ftell(f)) != -1 && !fseek(f, 0, SEEK_END) && (sz = ftell(f)) != -1 && !fseek(f, off, SEEK_SET)) ? (ImU64)sz : (ImU64)-1; }
 ImU64   ImFileRead(void* data, ImU64 sz, ImU64 count, ImFileHandle f)           { return fread(data, (size_t)sz, (size_t)count, f); }
 ImU64   ImFileWrite(const void* data, ImU64 sz, ImU64 count, ImFileHandle f)    { return fwrite(data, (size_t)sz, (size_t)count, f); }
-#endif // #ifndef IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS
+#else
+//Functions to redirect to our hook object function calls if it exists
+ImFileHandle      ImFileOpen(const char* filename, const char* mode) {
+    if (auto context = ImGui::GetCurrentContext()) {
+        if (ImIFileHelper* fileHelperPtr = context->FileHelper) {
+            return fileHelperPtr->ImFileOpen(filename, mode);
+        }
+    }
+    return nullptr;
+}
+bool              ImFileClose(ImFileHandle file) {
+    if (auto context = ImGui::GetCurrentContext()) {
+        if (ImIFileHelper* fileHelperPtr = context->FileHelper) {
+            return fileHelperPtr->ImFileClose(file);
+        }
+    }
+    return false;
+}
+ImU64             ImFileGetSize(ImFileHandle file) {
+    if (auto context = ImGui::GetCurrentContext()) {
+        if (ImIFileHelper* fileHelperPtr = context->FileHelper) {
+            return fileHelperPtr->ImFileGetSize(file);
+        }
+    }
+    return 0;
+}
+ImU64             ImFileRead(void* data, ImU64 size, ImU64 count, ImFileHandle file) {
+    if (auto context = ImGui::GetCurrentContext()) {
+        if (ImIFileHelper* fileHelperPtr = context->FileHelper) {
+            return fileHelperPtr->ImFileRead(data, size, count, file);
+        }
+    }
+    return 0;
+}
+ImU64             ImFileWrite(const void* data, ImU64 size, ImU64 count, ImFileHandle file) {
+    if (auto context = ImGui::GetCurrentContext()) {
+        if (ImIFileHelper* fileHelperPtr = context->FileHelper) {
+            return fileHelperPtr->ImFileWrite(data, size, count, file);
+        }
+    }
+    return 0;
+}
+#endif
 
 // Helper: Load file content into memory
 // Memory allocated with IM_ALLOC(), must be freed by user using IM_FREE() == ImGui::MemFree()

diff --git a/imgui_internal.h b/imgui_internal.h
@@ -372,8 +372,25 @@ IMGUI_API bool              ImFileClose(ImFileHandle file);
 IMGUI_API ImU64             ImFileGetSize(ImFileHandle file);
 IMGUI_API ImU64             ImFileRead(void* data, ImU64 size, ImU64 count, ImFileHandle file);
 IMGUI_API ImU64             ImFileWrite(const void* data, ImU64 size, ImU64 count, ImFileHandle file);
-#else
+#else //Bedrock File Handler Hook so we can use our own internal file handling
 #define IMGUI_DISABLE_TTY_FUNCTIONS // Can't use stdout, fflush if we are not using default file functions
+//We'll cast this to our own internal type as needed
+typedef void* ImFileHandle;
+//Helper struct for hooking file operations to external systems
+struct ImIFileHelper {
+    virtual ~ImIFileHelper() = default;
+    virtual ImFileHandle  ImFileOpen(const char* filename, const char* mode) = 0;
+    virtual bool          ImFileClose(ImFileHandle file) = 0;
+    virtual ImU64         ImFileGetSize(ImFileHandle file) = 0;
+    virtual ImU64         ImFileRead(void* data, ImU64 size, ImU64 count, ImFileHandle file) = 0;
+    virtual ImU64         ImFileWrite(const void* data, ImU64 size, ImU64 count, ImFileHandle file) = 0;
+};
+
+IMGUI_API ImFileHandle      ImFileOpen(const char* filename, const char* mode);
+IMGUI_API bool              ImFileClose(ImFileHandle file);
+IMGUI_API ImU64             ImFileGetSize(ImFileHandle file);
+IMGUI_API ImU64             ImFileRead(void* data, ImU64 size, ImU64 count, ImFileHandle file);
+IMGUI_API ImU64             ImFileWrite(const void* data, ImU64 size, ImU64 count, ImFileHandle file);
 #endif
 IMGUI_API void*             ImFileLoadToMemory(const char* filename, const char* mode, size_t* out_file_size = NULL, int padding_bytes = 0);
 
@@ -1598,6 +1615,9 @@ struct ImGuiContext
     ImChunkStream<ImGuiTableSettings>   SettingsTables;         // ImGuiTable .ini settings entries
     ImVector<ImGuiContextHook>          Hooks;                  // Hooks for extensions (e.g. test engine)
     ImGuiID                             HookIdNext;             // Next available HookId
+#ifdef IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS
+    ImIFileHelper* FileHelper = nullptr;                        // Hook object for external source to implement their own fileIO
+#endif
 
     // Capture/Logging
     bool                    LogEnabled;                         // Currently capturing