log properly the compiler used to compile Skia

Using #define's directly from VCL will report the compiler used
to compile VCL, which may be different from the one used for Skia.
Also truncate the log file on opening.

Change-Id: Iddf613613df20505f1abe1dd5468dcc8c7041410
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97090
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

RepositoryExternal.mk

@@ -131,6 +131,7 @@ $(call gb_LinkTarget_set_include,$(1),\
 	-I$(call gb_UnpackedTarball_get_dir,skia)/include/third_party/vulkan \
 	-I$(call gb_UnpackedTarball_get_dir,skia)/tools/gpu \
 	-I$(call gb_UnpackedTarball_get_dir,skia) \
+	-I$(SRCDIR)/external/skia/inc/ \
 	$$(INCLUDE) \
 )
 $(call gb_LinkTarget_use_libraries,$(1),skia)

external/skia/Library_skia.mk

@@ -85,10 +85,12 @@ $(eval $(call gb_Library_set_include,skia,\
     -I$(call gb_UnpackedTarball_get_dir,skia)/include/third_party/skcms/ \
     -I$(call gb_UnpackedTarball_get_dir,skia)/third_party/vulkanmemoryallocator/ \
     -I$(call gb_UnpackedTarball_get_dir,skia)/include/third_party/vulkan/ \
+    -I$(SRCDIR)/external/skia/inc/ \
 ))
 
 $(eval $(call gb_Library_add_exception_objects,skia,\
     external/skia/source/SkMemory_malloc \
+    external/skia/source/skia_compiler \
 ))
 
 $(eval $(call gb_Library_set_generated_cxx_suffix,skia,cpp))

external/skia/inc/skia_compiler.hxx

@@ -0,0 +1,13 @@
+/*
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SKIA_COMPILER_H
+#define SKIA_COMPILER_H
+
+#include <include/core/SkTypes.h>
+
+SK_API const char* skia_compiler_name();
+
+#endif

external/skia/source/skia_compiler.cxx

@@ -0,0 +1,20 @@
+/*
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <skia_compiler.hxx>
+
+// Get the type of compiler that Skia is compiled with.
+const char* skia_compiler_name()
+{
+#if defined __clang__
+    return "Clang";
+#elif defined __GNUC__
+    return "GCC";
+#elif defined _MSC_VER
+    return "MSVC";
+#else
+    return "?";
+#endif
+}

vcl/opengl/win/WinDeviceInfo.cxx

@@ -219,7 +219,7 @@ bool WinOpenGLDeviceInfo::isDeviceBlocked()
     OUString aCacheFolder = getCacheFolder();
 
     OUString aCacheFile(aCacheFolder + "/opengl_device.log");
-    SvFileStream aOpenGLLogFile(aCacheFile, StreamMode::WRITE);
+    SvFileStream aOpenGLLogFile(aCacheFile, StreamMode::WRITE|StreamMode::TRUNC);
 
     writeToLog(aOpenGLLogFile, "DriverVersion", maDriverVersion);
     writeToLog(aOpenGLLogFile, "DriverDate", maDriverDate);

vcl/skia/SkiaHelper.cxx

@@ -36,6 +36,7 @@ bool isVCLSkiaEnabled() { return false; }
 #include <SkCanvas.h>
 #include <SkPaint.h>
 #include <SkSurface.h>
+#include <skia_compiler.hxx>
 
 #ifdef DBG_UTIL
 #include <fstream>
@@ -109,7 +110,7 @@ static bool isVulkanBlacklisted(const VkPhysicalDeviceProperties& props)
     CrashReporter::addKeyValue("VulkanDeviceName", OUString::createFromAscii(props.deviceName),
                                CrashReporter::Write);
 
-    SvFileStream logFile(getCacheFolder() + "/skia.log", StreamMode::WRITE);
+    SvFileStream logFile(getCacheFolder() + "/skia.log", StreamMode::WRITE | StreamMode::TRUNC);
     writeToLog(logFile, "RenderMethod", "vulkan");
     writeToLog(logFile, "Vendor", vendorIdStr);
     writeToLog(logFile, "Device", deviceIdStr);
@@ -131,18 +132,10 @@ static bool isVulkanBlacklisted(const VkPhysicalDeviceProperties& props)
 
 static void writeSkiaRasterInfo()
 {
-    SvFileStream logFile(getCacheFolder() + "/skia.log", StreamMode::WRITE);
+    SvFileStream logFile(getCacheFolder() + "/skia.log", StreamMode::WRITE | StreamMode::TRUNC);
     writeToLog(logFile, "RenderMethod", "raster");
     // Log compiler, Skia works best when compiled with Clang.
-#if defined __clang__
-    writeToLog(logFile, "Compiler", "Clang");
-#elif defined __GNUC__
-    writeToLog(logFile, "Compiler", "GCC");
-#elif defined _MSC_VER
-    writeToLog(logFile, "Compiler", "MSVC");
-#else
-    writeToLog(logFile, "Compiler", "?");
-#endif
+    writeToLog(logFile, "Compiler", skia_compiler_name());
 }
 
 static sk_app::VulkanWindowContext::SharedGrContext getTemporaryGrContext();