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

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";

redo/comctl32_windows.go

@@ -1,72 +0,0 @@
-// 25 february 2014
-
-package ui
-
-import (
-	"fmt"
-	"io/ioutil"
-	"syscall"
-)
-
-// #include "winapi_windows.h"
-import "C"
-
-// TODO possibly rewrite the whole file access bits in C
-
-// pretty much every constant here except _WM_USER is from commctrl.h, except where noted
-
-/*
-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
-The activation context code itself is in comctl32_windows.c.
-*/
-func initCommonControls() (err error) {
-	manifestfile, err := ioutil.TempFile("", "gouicomctl32v6manifest")
-	if err != nil {
-		return fmt.Errorf("error creating synthesized manifest file: %v", err)
-	}
-	_, err = manifestfile.Write(manifest)
-	if err != nil {
-		return fmt.Errorf("error writing synthesized manifest file: %v", err)
-	}
-	filename := manifestfile.Name()
-	// we now have to close the file, otherwise ActivateActCtx() will complain that it's in use by another program
-	// if ioutil.TempFile() ever changes so that the file is deleted when it is closed, this will need to change
-	manifestfile.Close()
-
-	var errmsg *C.char
-
-	errcode := C.initCommonControls(toUTF16(filename), &errmsg)
-	if errcode != 0 || errmsg != nil {
-		return fmt.Errorf("error actually initializing comctl32.dll: %s: %v", C.GoString(errmsg), syscall.Errno(errcode))
-	}
-	return nil
-}
-
-var manifest = []byte(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
-<assemblyIdentity
-    version="1.0.0.0"
-    processorArchitecture="*"
-    name="CompanyName.ProductName.YourApplication"
-    type="win32"
-/>
-<description>Your application description here.</description>
-<dependency>
-    <dependentAssembly>
-        <assemblyIdentity
-            type="win32"
-            name="Microsoft.Windows.Common-Controls"
-            version="6.0.0.0"
-            processorArchitecture="*"
-            publicKeyToken="6595b64144ccf1df"
-            language="*"
-        />
-    </dependentAssembly>
-</dependency>
-</assembly>
-`)

redo/uitask_windows.go

@@ -21,8 +21,10 @@ func uiinit() error {
 	if errcode != 0 || errmsg != nil {
 		return fmt.Errorf("error initializing package ui on Windows: %s: %v", C.GoString(errmsg), syscall.Errno(errcode))
 	}
-	if err := initCommonControls(); err != nil {
+	errmsg = nil
-		return fmt.Errorf("error initializing comctl32.dll version 6: %v", err)
+	errcode = C.initCommonControls(&errmsg)
+	if errcode != 0 || errmsg != nil {
+		return fmt.Errorf("error initializing comctl32.dll: %s: %v", C.GoString(errmsg), syscall.Errno(errcode))
 	}
 	if err := makemsgwin(); err != nil {
 		return fmt.Errorf("error creating message-only window: %v", err)

redo/winapi_windows.h

@@ -38,7 +38,7 @@ extern HWND msgwin;
 extern DWORD makemsgwin(char **);
 
 /* comctl32_windows.c */
-extern DWORD initCommonControls(LPWSTR, char **);
+extern DWORD initCommonControls(char **);
 /* these are listed as WINAPI in both Microsoft's and MinGW's headers, but not on MSDN for some reason */
 extern BOOL (*WINAPI fv_SetWindowSubclass)(HWND, SUBCLASSPROC, UINT_PTR, DWORD_PTR);
 extern BOOL (*WINAPI fv_RemoveWindowSubclass)(HWND, SUBCLASSPROC, UINT_PTR);