tdf#75637: Resolve help images via a vnd.libreoffice.image UCP

...which uses the logic already available in VCL's ImplImageTree to locate the
image zip files and find fallbacks for incomplete themes and for localized
images.

Change-Id: Ic1c15fcacb6596a27a2b051093232902202bf472

4 files changed, 223 insertions, 0 deletions

diff --git a/ucb/Library_ucpimage.mk b/ucb/Library_ucpimage.mk
new file mode 100644
index 000000000000..9c683f748f75
--- /dev/null
+++ b/ucb/Library_ucpimage.mk
@@ -0,0 +1,33 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_Library_Library,ucpimage))
+
+$(eval $(call gb_Library_add_exception_objects,ucpimage, \
+    ucb/source/ucp/image/ucpimage \
+))
+
+$(eval $(call gb_Library_set_componentfile,ucpimage,ucb/source/ucp/image/ucpimage))
+
+$(eval $(call gb_Library_use_externals,ucpimage, \
+    boost_headers \
+))
+
+$(eval $(call gb_Library_use_libraries,ucpimage, \
+    cppu \
+    cppuhelper \
+    sal \
+    ucbhelper \
+    vcl \
+    $(gb_UWINAPI) \
+))
+
+$(eval $(call gb_Library_use_sdk_api,ucpimage))
+
+# vim: set noet sw=4 ts=4:
diff --git a/ucb/Module_ucb.mk b/ucb/Module_ucb.mk
index a143aca3f635..990161c95393 100644
--- a/ucb/Module_ucb.mk
+++ b/ucb/Module_ucb.mk
@@ -20,6 +20,7 @@ $(eval $(call gb_Module_add_targets,ucb,\
 	Library_ucpfile1 \
 	$(if $(ENABLE_CURL),Library_ucpftp1) \
 	Library_ucphier1 \
+	Library_ucpimage \
 	Library_ucppkg1 \
 	Library_ucptdoc1 \
 ))
diff --git a/ucb/source/ucp/image/ucpimage.component b/ucb/source/ucp/image/ucpimage.component
new file mode 100644
index 000000000000..6dba0ddc211e
--- /dev/null
+++ b/ucb/source/ucp/image/ucpimage.component
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+-->
+
+<component loader="com.sun.star.loader.SharedLibrary" environment="@CPPU_ENV@"
+    xmlns="http://openoffice.org/2010/uno-components">
+  <implementation name="com.sun.star.comp.ucb.ImageContentProvider"
+      constructor="com_sun_star_comp_ucb_ImageContentProvider_get_implementation">
+    <service name="com.sun.star.ucb.ImageContentProvider"/>
+  </implementation>
+</component>
diff --git a/ucb/source/ucp/image/ucpimage.cxx b/ucb/source/ucp/image/ucpimage.cxx
new file mode 100644
index 000000000000..fb3acff4e4ae
--- /dev/null
+++ b/ucb/source/ucp/image/ucpimage.cxx
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <sal/config.h>
+
+#include <cassert>
+
+#include <com/sun/star/lang/XServiceInfo.hpp>
+#include <com/sun/star/ucb/XContentProvider.hpp>
+#include <com/sun/star/uno/XComponentContext.hpp>
+#include <com/sun/star/uri/UriReferenceFactory.hpp>
+#include <cppuhelper/compbase.hxx>
+#include <cppuhelper/supportsservice.hxx>
+#include <osl/mutex.hxx>
+#include <rtl/uri.hxx>
+#include <rtl/ustrbuf.hxx>
+#include <vcl/implimagetree.hxx>
+#include <vcl/svapp.hxx>
+#include <ucbhelper/content.hxx>
+
+// A LO-private ("implementation detail") UCP used to access images from help
+// content, with theme fallback and localization support as provided by VCL's
+// ImplImageTree.
+//
+// The URL scheme is
+//
+//   "vnd.libreoffice.image://"<theme><path>["?lang="<language-tag>]
+
+namespace {
+
+class Provider final:
+    private osl::Mutex,
+    public cppu::WeakComponentImplHelper<
+        css::lang::XServiceInfo, css::ucb::XContentProvider>
+{
+public:
+    explicit Provider(
+        css::uno::Reference<css::uno::XComponentContext> const & context):
+        WeakComponentImplHelper(*static_cast<Mutex *>(this)), context_(context)
+    {}
+
+private:
+    OUString SAL_CALL getImplementationName()
+        throw (css::uno::RuntimeException, std::exception) override
+    { return OUString("com.sun.star.comp.ucb.ImageContentProvider"); }
+
+    sal_Bool SAL_CALL supportsService(OUString const & ServiceName)
+        throw (css::uno::RuntimeException, std::exception) override
+    { return cppu::supportsService(this, ServiceName); }
+
+    css::uno::Sequence<OUString> SAL_CALL getSupportedServiceNames()
+        throw (css::uno::RuntimeException, std::exception) override
+    {
+        return css::uno::Sequence<OUString>{
+            "com.sun.star.ucb.ImageContentProvider"};
+    }
+
+    css::uno::Reference<css::ucb::XContent> SAL_CALL queryContent(
+        css::uno::Reference<css::ucb::XContentIdentifier> const & Identifier)
+        throw (
+            css::ucb::IllegalIdentifierException, css::uno::RuntimeException,
+            std::exception)
+        override
+    {
+        css::uno::Reference<css::uno::XComponentContext> context;
+        {
+            osl::MutexGuard g(*this);
+            context = context_;
+        }
+        if (!context.is()) {
+            throw css::lang::DisposedException();
+        }
+        auto url(Identifier->getContentIdentifier());
+        auto uri(css::uri::UriReferenceFactory::create(context)->parse(url));
+        if (!(uri.is()
+              && uri->getScheme().equalsIgnoreAsciiCase(
+                  "vnd.libreoffice.image")))
+        {
+            throw css::ucb::IllegalIdentifierException(url);
+        }
+        auto auth(
+            rtl::Uri::decode(
+                uri->getAuthority(), rtl_UriDecodeStrict,
+                RTL_TEXTENCODING_UTF8));
+        if (auth.isEmpty()) {
+            throw css::ucb::IllegalIdentifierException(url);
+        }
+        auto path(uri->getPath());
+        if (path.isEmpty()) {
+            throw css::ucb::IllegalIdentifierException(url);
+        }
+        OUStringBuffer buf;
+        assert(path[0] == '/');
+        for (sal_Int32 i = 1;;) {
+            auto j = path.indexOf('/', i);
+            if (j == -1) {
+                j = path.getLength();
+            }
+            auto seg(
+                rtl::Uri::decode(
+                    path.copy(i, j - i), rtl_UriDecodeStrict,
+                    RTL_TEXTENCODING_UTF8));
+            if (seg.isEmpty()) {
+                throw css::ucb::IllegalIdentifierException(url);
+            }
+            if (i != 1) {
+                buf.append('/');
+            }
+            buf.append(seg);
+            if (j == path.getLength()) {
+                break;
+            }
+            i = j + 1;
+        }
+        auto decPath(buf.makeStringAndClear());
+        OUString lang;
+        if (uri->hasQuery()) {
+            if (!uri->getQuery().startsWith("lang=", &lang)) {
+                throw css::ucb::IllegalIdentifierException(url);
+            }
+            lang = rtl::Uri::decode(
+                lang, rtl_UriDecodeStrict, RTL_TEXTENCODING_UTF8);
+            if (lang.isEmpty()) {
+                throw css::ucb::IllegalIdentifierException(url);
+            }
+        }
+        OUString newUrl;
+        {
+            SolarMutexGuard g;
+            newUrl = ImplImageTree::get().getImageUrl(decPath, auth, lang);
+        }
+        ucbhelper::Content content;
+        return
+            ucbhelper::Content::create(
+                newUrl, css::uno::Reference<css::ucb::XCommandEnvironment>(),
+                context, content)
+            ? content.get() : css::uno::Reference<css::ucb::XContent>();
+    }
+
+    sal_Int32 SAL_CALL compareContentIds(
+        css::uno::Reference<css::ucb::XContentIdentifier> const & Id1,
+        css::uno::Reference<css::ucb::XContentIdentifier> const & Id2)
+        throw (css::uno::RuntimeException, std::exception) override
+    {
+        return Id1->getContentIdentifier().compareTo(
+            Id2->getContentIdentifier());
+    }
+
+    void SAL_CALL disposing() override {
+        context_.clear();
+    }
+
+    css::uno::Reference<css::uno::XComponentContext> context_;
+};
+
+}
+
+extern "C" SAL_DLLPUBLIC_EXPORT css::uno::XInterface * SAL_CALL
+com_sun_star_comp_ucb_ImageContentProvider_get_implementation(
+    css::uno::XComponentContext * context,
+    css::uno::Sequence<css::uno::Any> const &)
+{
+    return cppu::acquire(new Provider(context));
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */