TextEditor: add document content completer

Add completion based on words of the document. This provides basic
assistance for programming languages without a code model.

Task-number: QTCREATORBUG-13869
Change-Id: I3a9c59c741dfd6895442fc0524cfd1bd3b2b0111
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/texteditor/codeassist/codeassistant.cpp

@@ -252,7 +252,6 @@ void CodeAssistantPrivate::requestProposal(AssistReason reason,
     case IAssistProvider::Asynchronous: {
         processor->setAsyncCompletionAvailableHandler(
             [this, reason](IAssistProposal *newProposal){
-                QTC_CHECK(newProposal);
                 invalidateCurrentRequestData();
                 displayProposal(newProposal, reason);
 

src/plugins/texteditor/codeassist/documentcontentcompletion.cpp

@@ -0,0 +1,137 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 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 "documentcontentcompletion.h"
+
+#include "assistinterface.h"
+#include "assistproposalitem.h"
+#include "genericproposal.h"
+#include "genericproposalmodel.h"
+#include "iassistprocessor.h"
+#include "../snippets/snippetassistcollector.h"
+
+#include "utils/asconst.h"
+#include "utils/runextensions.h"
+
+#include <QElapsedTimer>
+#include <QRegularExpression>
+#include <QSet>
+#include <QTextBlock>
+#include <QTextDocument>
+
+using namespace TextEditor;
+
+class DocumentContentCompletionProcessor : public IAssistProcessor
+{
+public:
+    DocumentContentCompletionProcessor(const QString &snippetGroupId);
+
+    IAssistProposal *perform(const AssistInterface *interface) override;
+
+private:
+    TextEditor::SnippetAssistCollector m_snippetCollector;
+    IAssistProposal *createProposal(const AssistInterface *interface);
+};
+
+DocumentContentCompletionProvider::DocumentContentCompletionProvider(const QString &snippetGroup)
+    : m_snippetGroup(snippetGroup)
+{ }
+
+IAssistProvider::RunType DocumentContentCompletionProvider::runType() const
+{
+    return Asynchronous;
+}
+
+IAssistProcessor *DocumentContentCompletionProvider::createProcessor() const
+{
+    return new DocumentContentCompletionProcessor(m_snippetGroup);
+}
+
+DocumentContentCompletionProcessor::DocumentContentCompletionProcessor(const QString &snippetGroupId)
+    : m_snippetCollector(snippetGroupId, QIcon(":/texteditor/images/snippet.png"))
+{ }
+
+IAssistProposal *DocumentContentCompletionProcessor::perform(const AssistInterface *interface)
+{
+    Utils::onResultReady(Utils::runAsync(
+                             &DocumentContentCompletionProcessor::createProposal, this, interface),
+                         [this](IAssistProposal *proposal){
+        setAsyncProposalAvailable(proposal);
+    });
+    setPerformWasApplicable(true);
+    return nullptr;
+}
+
+static void generateProposalItems(const QString &text, QSet<QString> &words,
+                                  QList<AssistProposalItemInterface *> &items)
+{
+    static const QRegularExpression wordRE("([a-zA-Z_][a-zA-Z0-9_]{2,})");
+
+    QRegularExpressionMatch match;
+    int index = text.indexOf(wordRE, 0, &match);
+    while (index >= 0) {
+        const QString &word = match.captured();
+        if (!words.contains(word)) {
+            auto item = new AssistProposalItem();
+            item->setText(word);
+            items.append(item);
+            words.insert(word);
+        }
+        index += word.size();
+        index = text.indexOf(wordRE, index, &match);
+    }
+}
+
+IAssistProposal *DocumentContentCompletionProcessor::createProposal(
+        const AssistInterface *interface)
+{
+    QScopedPointer<const AssistInterface> assistInterface(interface);
+    int pos = interface->position();
+
+    QChar chr;
+    // Skip to the start of a name
+    do {
+        chr = interface->characterAt(--pos);
+    } while (chr.isLetterOrNumber() || chr == '_');
+
+    ++pos;
+
+    if (interface->reason() == IdleEditor) {
+        QChar characterUnderCursor = interface->characterAt(interface->position());
+        if (characterUnderCursor.isLetterOrNumber() || interface->position() - pos < 3)
+            return nullptr;
+    }
+
+    QSet<QString> words;
+    QList<AssistProposalItemInterface *> items = m_snippetCollector.collect();
+    QTextBlock block = interface->textDocument()->firstBlock();
+
+    while (block.isValid()) {
+        generateProposalItems(block.text(), words, items);
+        block = block.next();
+    }
+
+    return new GenericProposal(pos, items);
+}

src/plugins/texteditor/codeassist/documentcontentcompletion.h

@@ -0,0 +1,49 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 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 "completionassistprovider.h"
+
+#include "texteditor/texteditorconstants.h"
+
+namespace TextEditor {
+
+class AssistInterface;
+
+class TEXTEDITOR_EXPORT DocumentContentCompletionProvider : public CompletionAssistProvider
+{
+public:
+    DocumentContentCompletionProvider(
+            const QString &snippetGroup = QString(Constants::TEXT_SNIPPET_GROUP_ID));
+
+    RunType runType() const override;
+    IAssistProcessor *createProcessor() const override;
+
+private:
+    QString m_snippetGroup;
+};
+
+} // TextEditor

src/plugins/texteditor/texteditor.cpp

@@ -56,7 +56,7 @@
 #include <texteditor/codeassist/assistinterface.h>
 #include <texteditor/codeassist/codeassistant.h>
 #include <texteditor/codeassist/completionassistprovider.h>
-#include <texteditor/codeassist/keywordscompletionassist.h>
+#include <texteditor/codeassist/documentcontentcompletion.h>
 #include <texteditor/generichighlighter/context.h>
 #include <texteditor/generichighlighter/highlightdefinition.h>
 #include <texteditor/generichighlighter/highlighter.h>
@@ -8608,7 +8608,7 @@ void TextEditorFactory::setParenthesesMatchingEnabled(bool on)
 
 IEditor *TextEditorFactory::createEditor()
 {
-    static KeywordsCompletionAssistProvider basicSnippetProvider;
+    static DocumentContentCompletionProvider basicSnippetProvider;
     TextDocumentPtr doc(d->m_documentCreator());
 
     if (d->m_indenterCreator)

src/plugins/texteditor/texteditor.pro

@@ -84,6 +84,7 @@ SOURCES += texteditorplugin.cpp \
     codeassist/genericproposalwidget.cpp \
     codeassist/iassistproposalmodel.cpp \
     codeassist/textdocumentmanipulator.cpp \
+    codeassist/documentcontentcompletion.cpp\
     tabsettingswidget.cpp \
     simplecodestylepreferences.cpp \
     simplecodestylepreferenceswidget.cpp \
@@ -194,6 +195,7 @@ HEADERS += texteditorplugin.h \
     codeassist/iassistproposalmodel.h \
     codeassist/textdocumentmanipulator.h \
     codeassist/textdocumentmanipulatorinterface.h \
+    codeassist/documentcontentcompletion.h \
     tabsettingswidget.h \
     simplecodestylepreferences.h \
     simplecodestylepreferenceswidget.h \

src/plugins/texteditor/texteditor.qbs

@@ -160,6 +160,8 @@ Project {
                 "codeassistant.h",
                 "completionassistprovider.cpp",
                 "completionassistprovider.h",
+                "documentcontentcompletion.cpp",
+                "documentcontentcompletion.h",
                 "functionhintproposal.cpp",
                 "functionhintproposal.h",
                 "functionhintproposalwidget.cpp",