ClangCodeModel: Switch to LSP-based UI header approach

Generating ui headers in a well-known path and then including that one
in the compilation database does not work in the presence of multiple ui
files with the same name.
As it turns out, we don't have to generate any files at all; instead, we
pass the file contents directly to clangd, which then uses them when
parsing includes of the respective header.
User-visible behavior change apart from the abovementioned bug fix:
Tooltips and "follow symbol" on the include directive now always use the
actual location of the header provided by the build system.

Fixes: QTCREATORBUG-27584
Change-Id: I6b13e12cb3a365199567b0bc824d12b373117697
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/CMakeLists.txt

@@ -27,7 +27,6 @@ add_qtc_plugin(ClangCodeModel
     clangmodelmanagersupport.cpp clangmodelmanagersupport.h
     clangpreprocessorassistproposalitem.cpp clangpreprocessorassistproposalitem.h
     clangtextmark.cpp clangtextmark.h
-    clanguiheaderondiskmanager.cpp clanguiheaderondiskmanager.h
     clangutils.cpp clangutils.h
     tasktimers.cpp tasktimers.h
   EXPLICIT_MOC clangcodemodelplugin.h

src/plugins/clangcodemodel/clangcodemodel.qbs

@@ -54,8 +54,6 @@ QtcPlugin {
         "clangpreprocessorassistproposalitem.h",
         "clangtextmark.cpp",
         "clangtextmark.h",
-        "clanguiheaderondiskmanager.cpp",
-        "clanguiheaderondiskmanager.h",
         "clangutils.cpp",
         "clangutils.h",
         "tasktimers.cpp",

src/plugins/clangcodemodel/clangmodelmanagersupport.cpp

@@ -100,6 +100,30 @@ static const QList<TextEditor::TextDocument *> allCppDocuments()
     return Utils::qobject_container_cast<TextEditor::TextDocument *>(documents);
 }
 
+static bool fileIsProjectBuildArtifact(const Client *client, const Utils::FilePath &filePath)
+{
+    if (const auto p = client->project()) {
+        if (const auto t = p->activeTarget()) {
+            if (const auto bc = t->activeBuildConfiguration()) {
+                if (filePath.isChildOf(bc->buildDirectory()))
+                    return true;
+            }
+        }
+    }
+    return false;
+}
+
+static Client *clientForGeneratedFile(const Utils::FilePath &filePath)
+{
+    for (Client * const client : LanguageClientManager::clients()) {
+        if (qobject_cast<ClangdClient *>(client) && client->reachable()
+                && fileIsProjectBuildArtifact(client, filePath)) {
+            return client;
+        }
+    }
+    return nullptr;
+}
+
 ClangModelManagerSupport::ClangModelManagerSupport()
 {
     QTC_CHECK(!m_instance);
@@ -344,7 +368,7 @@ void ClangModelManagerSupport::updateLanguageClient(
         if (Client * const oldClient = clientForProject(project))
             LanguageClientManager::shutdownClient(oldClient);
         ClangdClient * const client = createClient(project, jsonDbDir);
-        connect(client, &Client::initialized, this, [client, project, projectInfo, jsonDbDir] {
+        connect(client, &Client::initialized, this, [this, client, project, projectInfo, jsonDbDir] {
             using namespace ProjectExplorer;
             if (!SessionManager::hasProject(project))
                 return;
@@ -384,6 +408,23 @@ void ClangModelManagerSupport::updateLanguageClient(
                 }
             }
 
+            for (auto it = m_queuedShadowDocuments.begin(); it != m_queuedShadowDocuments.end();) {
+                if (fileIsProjectBuildArtifact(client, it.key())) {
+                    if (it.value().isEmpty())
+                        client->removeShadowDocument(it.key());
+                    else
+                        client->setShadowDocument(it.key(), it.value());
+                    ClangdClient::handleUiHeaderChange(it.key().fileName());
+                    it = m_queuedShadowDocuments.erase(it);
+                } else {
+                    ++it;
+                }
+            }
+            connect(client, &Client::shadowDocumentSwitched, this,
+                    [](const Utils::FilePath &fp) {
+                        ClangdClient::handleUiHeaderChange(fp.fileName());
+            });
+
             if (client->state() == Client::Initialized)
                 updateParserConfig();
             else
@@ -593,18 +634,28 @@ void ClangModelManagerSupport::onAbstractEditorSupportContentsUpdated(const QStr
 
     if (content.size() == 0)
         return; // Generation not yet finished.
-
-    m_uiHeaderOnDiskManager.write(filePath, content);
-    ClangdClient::handleUiHeaderChange(Utils::FilePath::fromString(filePath).fileName());
+    const auto fp = Utils::FilePath::fromString(filePath);
+    const QString stringContent = QString::fromUtf8(content);
+    if (Client * const client = clientForGeneratedFile(fp)) {
+        client->setShadowDocument(fp, stringContent);
+        ClangdClient::handleUiHeaderChange(fp.fileName());
+        QTC_CHECK(m_queuedShadowDocuments.remove(fp) == 0);
+    } else  {
+        m_queuedShadowDocuments.insert(fp, stringContent);
+    }
 }
 
 void ClangModelManagerSupport::onAbstractEditorSupportRemoved(const QString &filePath)
 {
     QTC_ASSERT(!filePath.isEmpty(), return);
 
-    if (!cppModelManager()->cppEditorDocument(filePath)) {
-        m_uiHeaderOnDiskManager.remove(filePath);
-        ClangdClient::handleUiHeaderChange(Utils::FilePath::fromString(filePath).fileName());
+    const auto fp = Utils::FilePath::fromString(filePath);
+    if (Client * const client = clientForGeneratedFile(fp)) {
+        client->removeShadowDocument(fp);
+        ClangdClient::handleUiHeaderChange(fp.fileName());
+        QTC_CHECK(m_queuedShadowDocuments.remove(fp) == 0);
+    } else {
+        m_queuedShadowDocuments.insert(fp, {});
     }
 }
 
@@ -738,16 +789,6 @@ ClangModelManagerSupport *ClangModelManagerSupport::instance()
     return m_instance;
 }
 
-QString ClangModelManagerSupport::dummyUiHeaderOnDiskPath(const QString &filePath) const
-{
-    return m_uiHeaderOnDiskManager.mapPath(filePath);
-}
-
-QString ClangModelManagerSupport::dummyUiHeaderOnDiskDirPath() const
-{
-    return m_uiHeaderOnDiskManager.directoryPath();
-}
-
 QString ClangModelManagerSupportProvider::id() const
 {
     return QLatin1String(Constants::CLANG_MODELMANAGERSUPPORT_ID);

src/plugins/clangcodemodel/clangmodelmanagersupport.h

@@ -25,14 +25,14 @@
 
 #pragma once
 
-#include "clanguiheaderondiskmanager.h"
-
 #include <cppeditor/cppmodelmanagersupport.h>
 #include <cppeditor/projectinfo.h>
 
+#include <utils/filepath.h>
 #include <utils/futuresynchronizer.h>
 #include <utils/id.h>
 
+#include <QHash>
 #include <QObject>
 #include <QPointer>
 
@@ -70,9 +70,6 @@ public:
     std::unique_ptr<CppEditor::AbstractOverviewModel> createOverviewModel() override;
     bool usesClangd(const TextEditor::TextDocument *document) const override;
 
-    QString dummyUiHeaderOnDiskDirPath() const;
-    QString dummyUiHeaderOnDiskPath(const QString &filePath) const;
-
     ClangdClient *clientForProject(const ProjectExplorer::Project *project) const;
     ClangdClient *clientForFile(const Utils::FilePath &file) const;
 
@@ -122,10 +119,9 @@ private:
     void watchForExternalChanges();
     void watchForInternalChanges();
 
-    UiHeaderOnDiskManager m_uiHeaderOnDiskManager;
-
     Utils::FutureSynchronizer m_generatorSynchronizer;
     QList<QPointer<ClangdClient>> m_clientsToRestart;
+    QHash<Utils::FilePath, QString> m_queuedShadowDocuments;
 };
 
 class ClangModelManagerSupportProvider : public CppEditor::ModelManagerSupportProvider

src/plugins/clangcodemodel/clanguiheaderondiskmanager.cpp

@@ -1,75 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#include "clanguiheaderondiskmanager.h"
-
-#include <QFile>
-#include <QFileInfo>
-
-#include <utils/fileutils.h>
-#include <utils/qtcassert.h>
-
-namespace ClangCodeModel {
-namespace Internal {
-
-UiHeaderOnDiskManager::UiHeaderOnDiskManager() : m_temporaryDir("clang-uiheader-XXXXXX")
-{
-    QTC_CHECK(m_temporaryDir.isValid());
-}
-
-QString UiHeaderOnDiskManager::write(const QString &filePath, const QByteArray &content)
-{
-    const QString mappedPath = mapPath(filePath);
-    QFile file(mappedPath);
-    const bool fileCreated = file.open(QFile::WriteOnly);
-    const qint64 bytesWritten = file.write(content);
-    QTC_CHECK(fileCreated && bytesWritten != -1);
-
-    return mappedPath;
-}
-
-QString UiHeaderOnDiskManager::remove(const QString &filePath)
-{
-    const QString mappedPath = mapPath(filePath);
-    if (QFileInfo::exists(mappedPath)) {
-        const bool fileRemoved = QFile::remove(mappedPath);
-        QTC_CHECK(fileRemoved);
-    }
-
-    return mappedPath;
-}
-
-QString UiHeaderOnDiskManager::directoryPath() const
-{
-    return m_temporaryDir.path().path();
-}
-
-QString UiHeaderOnDiskManager::mapPath(const QString &filePath) const
-{
-    return directoryPath() + '/' + QFileInfo(filePath).fileName();
-}
-
-} // namespace Internal
-} // namespace ClangCodeModel

src/plugins/clangcodemodel/clanguiheaderondiskmanager.h

@@ -1,50 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#pragma once
-
-#include <utils/temporarydirectory.h>
-
-namespace ClangCodeModel {
-namespace Internal {
-
-// TODO: Remove once libclang supports unsaved files that do not exist.
-class UiHeaderOnDiskManager
-{
-public:
-    UiHeaderOnDiskManager();
-
-    QString write(const QString &filePath, const QByteArray &content);
-    QString remove(const QString &filePath);
-
-    QString mapPath(const QString &filePath) const;
-    QString directoryPath() const;
-
-private:
-    ::Utils::TemporaryDirectory m_temporaryDir;
-};
-
-} // namespace Internal
-} // namespace ClangCodeModel

src/plugins/clangcodemodel/clangutils.cpp

@@ -25,8 +25,6 @@
 
 #include "clangutils.h"
 
-#include "clangmodelmanagersupport.h"
-
 #include <coreplugin/icore.h>
 #include <coreplugin/idocument.h>
 #include <cppeditor/baseeditordocumentparser.h>
@@ -355,12 +353,6 @@ CompilerOptionsBuilder clangOptionsBuilder(const ProjectPart &projectPart,
                                           useBuildSystemWarnings, clangIncludeDir);
     optionsBuilder.provideAdditionalMacros({ProjectExplorer::Macro("Q_CREATOR_RUN", "1")});
     optionsBuilder.build(ProjectFile::Unclassified, UsePrecompiledHeaders::No);
-    const QString uiIncludePath
-            = ClangModelManagerSupport::instance()->dummyUiHeaderOnDiskDirPath();
-    if (!uiIncludePath.isEmpty()) {
-        optionsBuilder.prepend(QDir::toNativeSeparators(uiIncludePath));
-        optionsBuilder.prepend("-I");
-    }
     optionsBuilder.add("-fmessage-length=0", /*gccOnlyOption=*/true);
     optionsBuilder.add("-fdiagnostics-show-note-include-stack", /*gccOnlyOption=*/true);
     optionsBuilder.add("-fretain-comments-from-system-headers", /*gccOnlyOption=*/true);

src/plugins/languageclient/client.cpp

@@ -260,6 +260,9 @@ public:
                             const LanguageServerProtocol::Range &range,
                             const QList<LanguageServerProtocol::Diagnostic> &diagnostics);
     void documentClosed(Core::IDocument *document);
+    void sendOpenNotification(const FilePath &filePath, const QString &mimeType,
+                              const QString &content, int version);
+    void sendCloseNotification(const FilePath &filePath);
 
     bool reset();
 
@@ -270,6 +273,11 @@ public:
     LanguageFilter m_languagFilter;
     QJsonObject m_initializationOptions;
     QMap<TextEditor::TextDocument *, QString> m_openedDocument;
+
+    // Used for build system artifacts (e.g. UI headers) that Qt Creator "live-generates" ahead of
+    // the build.
+    QMap<FilePath, QString> m_shadowDocuments;
+
     QSet<TextEditor::TextDocument *> m_postponedDocuments;
     QMap<Utils::FilePath, int> m_documentVersions;
     std::unordered_map<TextEditor::TextDocument *,
@@ -568,6 +576,11 @@ void Client::openDocument(TextEditor::TextDocument *document)
     }
 
     const FilePath &filePath = document->filePath();
+    if (d->m_shadowDocuments.contains(filePath)) {
+        d->sendCloseNotification(filePath);
+        emit shadowDocumentSwitched(filePath);
+    }
+
     const QString method(DidOpenTextDocumentNotification::methodName);
     if (Utils::optional<bool> registered = d->m_dynamicCapabilities.isRegistered(method)) {
         if (!*registered)
@@ -591,14 +604,10 @@ void Client::openDocument(TextEditor::TextDocument *document)
             [this, document](int position, int charsRemoved, int charsAdded) {
         documentContentsChanged(document, position, charsRemoved, charsAdded);
     });
-    TextDocumentItem item;
-    item.setLanguageId(TextDocumentItem::mimeTypeToLanguageId(document->mimeType()));
-    item.setUri(DocumentUri::fromFilePath(filePath));
-    item.setText(document->plainText());
     if (!d->m_documentVersions.contains(filePath))
         d->m_documentVersions[filePath] = 0;
-    item.setVersion(d->m_documentVersions[filePath]);
-    sendMessage(DidOpenTextDocumentNotification(DidOpenTextDocumentParams(item)));
+    d->sendOpenNotification(filePath, document->mimeType(), document->plainText(),
+                            d->m_documentVersions[filePath]);
     handleDocumentOpened(document);
 
     const Client *currentClient = LanguageClientManager::clientForDocument(document);
@@ -635,15 +644,21 @@ void Client::cancelRequest(const MessageId &id)
 void Client::closeDocument(TextEditor::TextDocument *document)
 {
     deactivateDocument(document);
-    const DocumentUri &uri = DocumentUri::fromFilePath(document->filePath());
     d->m_postponedDocuments.remove(document);
     if (d->m_openedDocument.remove(document) != 0) {
         handleDocumentClosed(document);
-        if (d->m_state == Initialized) {
-            DidCloseTextDocumentParams params(TextDocumentIdentifier{uri});
-            sendMessage(DidCloseTextDocumentNotification(params));
-        }
+        if (d->m_state == Initialized)
+            d->sendCloseNotification(document->filePath());
     }
+
+    if (d->m_state != Initialized)
+        return;
+    const auto shadowIt = d->m_shadowDocuments.constFind(document->filePath());
+    if (shadowIt == d->m_shadowDocuments.constEnd())
+        return;
+    d->sendOpenNotification(document->filePath(), document->mimeType(), shadowIt.value(),
+                            ++d->m_documentVersions[document->filePath()]);
+    emit shadowDocumentSwitched(document->filePath());
 }
 
 void ClientPrivate::updateCompletionProvider(TextEditor::TextDocument *document)
@@ -834,6 +849,25 @@ void ClientPrivate::documentClosed(Core::IDocument *document)
         q->closeDocument(textDocument);
 }
 
+void ClientPrivate::sendOpenNotification(const FilePath &filePath, const QString &mimeType,
+                                         const QString &content, int version)
+{
+    TextDocumentItem item;
+    item.setLanguageId(TextDocumentItem::mimeTypeToLanguageId(mimeType));
+    item.setUri(DocumentUri::fromFilePath(filePath));
+    item.setText(content);
+    item.setVersion(version);
+    q->sendMessage(DidOpenTextDocumentNotification(DidOpenTextDocumentParams(item)),
+                   Client::SendDocUpdates::Ignore);
+}
+
+void ClientPrivate::sendCloseNotification(const FilePath &filePath)
+{
+    q->sendMessage(DidCloseTextDocumentNotification(DidCloseTextDocumentParams(
+            TextDocumentIdentifier{DocumentUri::fromFilePath(filePath)})),
+                   Client::SendDocUpdates::Ignore);
+}
+
 bool Client::documentOpen(const TextEditor::TextDocument *document) const
 {
     return d->m_openedDocument.contains(const_cast<TextEditor::TextDocument *>(document));
@@ -848,6 +882,41 @@ TextEditor::TextDocument *Client::documentForFilePath(const Utils::FilePath &fil
     return nullptr;
 }
 
+void Client::setShadowDocument(const Utils::FilePath &filePath, const QString &content)
+{
+    QTC_ASSERT(reachable(), return);
+    const auto it = d->m_shadowDocuments.find(filePath);
+    const bool isNew = it == d->m_shadowDocuments.end();
+    if (isNew)
+        d->m_shadowDocuments.insert(filePath, content);
+    else
+        it.value() = content;
+    if (documentForFilePath(filePath))
+        return;
+    const auto uri = DocumentUri::fromFilePath(filePath);
+    if (isNew) {
+        const QString mimeType = mimeTypeForFile(
+                    filePath.toString(), MimeMatchMode::MatchExtension).name();
+        d->sendOpenNotification(filePath, mimeType, content, 0);
+    }
+
+    VersionedTextDocumentIdentifier docId(uri);
+    docId.setVersion(++d->m_documentVersions[filePath]);
+    const DidChangeTextDocumentParams params(docId, content);
+    sendMessage(DidChangeTextDocumentNotification(params), SendDocUpdates::Ignore);
+}
+
+void Client::removeShadowDocument(const Utils::FilePath &filePath)
+{
+    const auto it = d->m_shadowDocuments.find(filePath);
+    if (it == d->m_shadowDocuments.end())
+        return;
+    d->m_shadowDocuments.erase(it);
+    if (documentForFilePath(filePath))
+        return;
+    d->sendCloseNotification(filePath);
+}
+
 void Client::documentContentsSaved(TextEditor::TextDocument *document)
 {
     if (!d->m_openedDocument.contains(document))
@@ -1406,6 +1475,7 @@ bool ClientPrivate::reset()
     qDeleteAll(m_documentHighlightsTimer);
     m_documentHighlightsTimer.clear();
     m_progressManager.reset();
+    m_shadowDocuments.clear();
     m_documentVersions.clear();
     return true;
 }

src/plugins/languageclient/client.h

@@ -136,6 +136,8 @@ public:
     void deactivateDocument(TextEditor::TextDocument *document);
     bool documentOpen(const TextEditor::TextDocument *document) const;
     TextEditor::TextDocument *documentForFilePath(const Utils::FilePath &file) const;
+    void setShadowDocument(const Utils::FilePath &filePath, const QString &contents);
+    void removeShadowDocument(const Utils::FilePath &filePath);
     void documentContentsSaved(TextEditor::TextDocument *document);
     void documentWillSave(Core::IDocument *document);
     void documentContentsChanged(TextEditor::TextDocument *document,
@@ -205,6 +207,7 @@ signals:
     void capabilitiesChanged(const DynamicCapabilities &capabilities);
     void documentUpdated(TextEditor::TextDocument *document);
     void workDone(const LanguageServerProtocol::ProgressToken &token);
+    void shadowDocumentSwitched(const Utils::FilePath &filePath);
     void finished();
 
 protected:

src/plugins/languageclient/languageclientmanager.cpp

@@ -181,7 +181,7 @@ Client *LanguageClientManager::startClient(const BaseSettings *setting,
     return client;
 }
 
-QList<Client *> LanguageClientManager::clients()
+const QList<Client *> LanguageClientManager::clients()
 {
     QTC_ASSERT(managerInstance, return {});
     return managerInstance->m_clients;

src/plugins/languageclient/languageclientmanager.h

@@ -62,7 +62,7 @@ public:
     static void clientStarted(Client *client);
     static void clientFinished(Client *client);
     static Client *startClient(const BaseSettings *setting, ProjectExplorer::Project *project = nullptr);
-    static QList<Client *> clients();
+    static const QList<Client *> clients();
     static void addClient(Client *client);
 
     static void addExclusiveRequest(const LanguageServerProtocol::MessageId &id, Client *client);

tests/unit/unittest/CMakeLists.txt

@@ -332,7 +332,6 @@ extend_qtc_test(unittest
   SOURCES_PREFIX ../../../src/plugins/clangcodemodel
   SOURCES
     clangactivationsequenceprocessor.cpp clangactivationsequenceprocessor.h
-    clanguiheaderondiskmanager.cpp clanguiheaderondiskmanager.h
 )
 
 find_package(yaml-cpp QUIET MODULE)

tests/unit/unittest/unittest.qbs

@@ -203,8 +203,6 @@ Project {
             files: [
                 "clangactivationsequenceprocessor.cpp",
                 "clangactivationsequenceprocessor.h",
-                "clanguiheaderondiskmanager.cpp",
-                "clanguiheaderondiskmanager.h",
             ]
         }