Migrated all Common Controls version 6 initialization on the Windows backend to C.

1 files changed, 53 insertions, 2 deletions

diff --git a/redo/comctl32_windows.c b/redo/comctl32_windows.c
index 09b9605..df1bdcd 100644
--- a/redo/comctl32_windows.c
+++ b/redo/comctl32_windows.c
@@ -16,8 +16,24 @@ LRESULT (*WINAPI fv_DefSubclassProc)(HWND, UINT, WPARAM, LPARAM);
 	ICC_LISTVIEW_CLASSES |		/* list views */			\
 	0)
 
-DWORD initCommonControls(LPWSTR manifest, char **errmsg)
+/* note that this is an 8-bit character string we're writing; see the encoding clause */
+static const char manifest[] = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n<assembly xmlns=\"urn:schemas-microsoft-com:asm.v1\" manifestVersion=\"1.0\">\n<assemblyIdentity\n    version=\"1.0.0.0\"\n    processorArchitecture=\"*\"\n    name=\"CompanyName.ProductName.YourApplication\"\n    type=\"win32\"\n/>\n<description>Your application description here.</description>\n<dependency>\n    <dependentAssembly>\n        <assemblyIdentity\n            type=\"win32\"\n            name=\"Microsoft.Windows.Common-Controls\"\n            version=\"6.0.0.0\"\n            processorArchitecture=\"*\"\n            publicKeyToken=\"6595b64144ccf1df\"\n            language=\"*\"\n        />\n    </dependentAssembly>\n</dependency>\n</assembly>\n";
+
+/*
+Windows requires a manifest file to enable Common Controls version 6.
+The only way to not require an external manifest is to synthesize the manifest ourselves.
+We can use the activation context API to load it at runtime.
+References:
+- http://stackoverflow.com/questions/4308503/how-to-enable-visual-styles-without-a-manifest
+- http://support.microsoft.com/kb/830033
+Because neither Go nor MinGW have ways to compile in resources like this (as far as I know), we have to do the work ourselves.
+*/
+DWORD initCommonControls(char **errmsg)
 {
+	WCHAR temppath[MAX_PATH + 1];
+	WCHAR filename[MAX_PATH + 1];
+	HANDLE file;
+	DWORD nExpected, nGot;
 	ACTCTX actctx;
 	HANDLE ac;
 	INITCOMMONCONTROLSEX icc;
@@ -25,10 +41,45 @@ DWORD initCommonControls(LPWSTR manifest, char **errmsg)
 	/* this is listed as WINAPI in both Microsoft's and MinGW's headers, but not on MSDN for some reason */
 	BOOL (*WINAPI ficc)(const LPINITCOMMONCONTROLSEX);
 
+	if (GetTempPathW(MAX_PATH + 1, temppath) == 0) {
+		*errmsg = "error getting temporary path for writing manifest file";
+		return GetLastError();
+	}
+	if (GetTempFileNameW(temppath, L"manifest", 0, filename) == 0) {
+		*errmsg = "error getting temporary filename for writing manifest file";
+		return GetLastError();
+	}
+	file = CreateFileW(filename, GENERIC_WRITE,
+		0,			/* don't share while writing */
+		NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+	if (file == NULL) {
+		*errmsg = "error creating manifest file";
+		return GetLastError();
+	}
+	nExpected = strlen(manifest);		/* TODO make static */
+	SetLastError(0);		/* catch errorless short writes */
+	if (WriteFile(file, manifest, nExpected, &nGot, NULL) == 0) {
+		*errmsg = "error writing manifest file";
+		return GetLastError();
+	}
+	if (nGot != nExpected) {
+		DWORD lasterr;
+
+		lasterr = GetLastError();
+		*errmsg = "short write to manifest file";
+		if (lasterr == 0)
+			*errmsg = "short write to manifest file without error code";
+		return lasterr;
+	}
+	if (CloseHandle(file) == 0) {
+		*errmsg = "error closing manifest file (this IS an error here because not doing so will prevent Windows from being able to use the manifest file in an activation context)";
+		return GetLastError();
+	}
+
 	ZeroMemory(&actctx, sizeof (ACTCTX));
 	actctx.cbSize = sizeof (ACTCTX);
 	actctx.dwFlags = ACTCTX_FLAG_SET_PROCESS_DEFAULT;
-	actctx.lpSource = manifest;
+	actctx.lpSource = filename;
 	ac = CreateActCtx(&actctx);
 	if (ac == INVALID_HANDLE_VALUE) {
 		*errmsg = "error creating activation context for synthesized manifest file";