A remotable font management interface and DirectWrite implementation.

src/utils/win/SkDWrite.cpp

Index: src/utils/win/SkDWrite.cpp
===================================================================
--- src/utils/win/SkDWrite.cpp	(revision 0)
+++ src/utils/win/SkDWrite.cpp	(working copy)
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkDWrite.h"
+#include "SkHRESULT.h"
+#include "SkOnce.h"
+#include "SkString.h"
+
+#include <dwrite.h>
+
+static IDWriteFactory* gDWriteFactory = NULL;
+
+static void create_dwrite_factory(IDWriteFactory** factory) {
+    typedef decltype(DWriteCreateFactory)* DWriteCreateFactoryProc;
+    DWriteCreateFactoryProc dWriteCreateFactoryProc = reinterpret_cast<DWriteCreateFactoryProc>(
+        GetProcAddress(LoadLibraryW(L"dwrite.dll"), "DWriteCreateFactory"));
+
+    if (!dWriteCreateFactoryProc) {
+        HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
+        if (!IS_ERROR(hr)) {
+            hr = ERROR_PROC_NOT_FOUND;
+        }
+        HRVM(hr, "Could not get DWriteCreateFactory proc.");
+    }
+
+    HRVM(dWriteCreateFactoryProc(DWRITE_FACTORY_TYPE_SHARED,
+                                 __uuidof(IDWriteFactory),
+                                 reinterpret_cast<IUnknown**>(factory)),
+         "Could not create DirectWrite factory.");
+}
+
+static void release_dwrite_factory() {
+    if (gDWriteFactory) {
+        gDWriteFactory->Release();
+    }
+}
+
+IDWriteFactory* sk_get_dwrite_factory() {
+    SK_DECLARE_STATIC_ONCE(once);
+    SkOnce(&once, create_dwrite_factory, &gDWriteFactory, release_dwrite_factory);
+
+    return gDWriteFactory;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// String conversion
+
+/** Converts a utf8 string to a WCHAR string. */
+HRESULT sk_cstring_to_wchar(const char* skname, SkSMallocWCHAR* name) {
+    int wlen = MultiByteToWideChar(CP_UTF8, 0, skname, -1, NULL, 0);
+    if (0 == wlen) {
+        HRM(HRESULT_FROM_WIN32(GetLastError()),
+            "Could not get length for wchar to utf-8 conversion.");
+    }
+    name->reset(wlen);
+    wlen = MultiByteToWideChar(CP_UTF8, 0, skname, -1, name->get(), wlen);
+    if (0 == wlen) {
+        HRM(HRESULT_FROM_WIN32(GetLastError()), "Could not convert wchar to utf-8.");
+    }
+    return S_OK;
+}
+
+/** Converts a WCHAR string to a utf8 string. */
+HRESULT sk_wchar_to_skstring(WCHAR* name, SkString* skname) {
+    int len = WideCharToMultiByte(CP_UTF8, 0, name, -1, NULL, 0, NULL, NULL);
+    if (0 == len) {
+        HRM(HRESULT_FROM_WIN32(GetLastError()),
+            "Could not get length for utf-8 to wchar conversion.");
+    }
+    skname->resize(len - 1);
+
+    // TODO: remove after https://code.google.com/p/skia/issues/detail?id=1989 is fixed.
+    // If we resize to 0 then the skname points to gEmptyRec (the unique empty SkString::Rec).
+    // gEmptyRec is static const and on Windows this means the value is in a read only page.
+    // Writing to it in the following call to WideCharToMultiByte will cause an access violation.
+    if (1 == len) {
+        return S_OK;
+    }
+
+    len = WideCharToMultiByte(CP_UTF8, 0, name, -1, skname->writable_str(), len, NULL, NULL);
+    if (0 == len) {
+        HRM(HRESULT_FROM_WIN32(GetLastError()), "Could not convert utf-8 to wchar.");
+    }
+    return S_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Locale
+
+void sk_get_locale_string(IDWriteLocalizedStrings* names, const WCHAR* preferedLocale,
+                          SkString* skname) {
+    UINT32 nameIndex = 0;
+    if (preferedLocale) {
+        // Ignore any errors and continue with index 0 if there is a problem.
+        BOOL nameExists;
+        names->FindLocaleName(preferedLocale, &nameIndex, &nameExists);
+        if (!nameExists) {
+            nameIndex = 0;
+        }
+    }
+
+    UINT32 nameLength;
+    HRVM(names->GetStringLength(nameIndex, &nameLength), "Could not get name length.");
+    nameLength += 1;
+
+    SkSMallocWCHAR name(nameLength);
+    HRVM(names->GetString(nameIndex, name.get(), nameLength), "Could not get string.");
+
+    HRV(sk_wchar_to_skstring(name.get(), skname));
+}
+
+HRESULT SkGetGetUserDefaultLocaleNameProc(SkGetUserDefaultLocaleNameProc* proc) {
+    *proc = reinterpret_cast<SkGetUserDefaultLocaleNameProc>(
+        GetProcAddress(LoadLibraryW(L"Kernel32.dll"), "GetUserDefaultLocaleName")
+    );
+    if (!*proc) {
+        HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
+        if (!IS_ERROR(hr)) {
+            hr = ERROR_PROC_NOT_FOUND;
+        }
+        return hr;
+    }
+    return S_OK;
+}