Utils: Move template file processing from projectexplorer to utils

I want to use it e.g. for snippets and the TextEditor plugin may
not depend on the ProjectExplorer, so the code has to move.

This adds a dependency on QtQml to Utils, but that does not really
matter since that is loaded into QtCreator anyway.

Change-Id: Iada9f40b2966a1fc41631ab33da09812ad67d967
Reviewed-by: Daniel Teske <[email protected]>

5 files changed, 377 insertions, 2 deletions

diff --git a/src/libs/utils/templateengine.cpp b/src/libs/utils/templateengine.cpp
new file mode 100644
index 00000000000..c372276e7a5
--- /dev/null
+++ b/src/libs/utils/templateengine.cpp
@@ -0,0 +1,316 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "templateengine.h"
+
+#include "qtcassert.h"
+
+#include <QJSEngine>
+#include <QStack>
+
+namespace Utils {
+
+namespace Internal {
+
+// Preprocessor: Conditional section type.
+enum PreprocessorSection {
+    IfSection,
+    ElsifSection,
+    ElseSection,
+    EndifSection,
+    OtherSection
+};
+
+// Preprocessor: Section stack entry containing nested '@if' section
+// state.
+class PreprocessStackEntry {
+public:
+    PreprocessStackEntry(PreprocessorSection section = OtherSection,
+                         bool parentEnabled = true,
+                         bool condition = false,
+                         bool anyIfClauseMatched = false);
+
+    PreprocessorSection section;
+    bool parentEnabled;
+    bool condition;          // Current 'if/elsif' section is enabled.
+    bool anyIfClauseMatched; // Determines if 'else' triggers
+};
+
+PreprocessStackEntry::PreprocessStackEntry(PreprocessorSection s, bool p, bool c, bool a) :
+    section(s), parentEnabled(p), condition(c), anyIfClauseMatched(a)
+{ }
+
+// Context for preprocessing.
+class PreprocessContext {
+public:
+    PreprocessContext();
+    bool process(const QString &in, QString *out, QString *errorMessage);
+
+private:
+    void reset();
+    PreprocessorSection preprocessorLine(const QString & in, QString *ifExpression) const;
+
+    mutable QRegExp m_ifPattern;
+    mutable QRegExp m_elsifPattern;
+    mutable QRegExp m_elsePattern;
+    mutable QRegExp m_endifPattern;
+
+    QStack<PreprocessStackEntry> m_sectionStack;
+    QJSEngine m_scriptEngine;
+};
+
+PreprocessContext::PreprocessContext() :
+    // Cut out expression for 'if/elsif '
+    m_ifPattern(QLatin1String("^([\\s]*@[\\s]*if[\\s]*)(.*)$")),
+    m_elsifPattern(QLatin1String("^([\\s]*@[\\s]*elsif[\\s]*)(.*)$")),
+    m_elsePattern(QLatin1String("^[\\s]*@[\\s]*else.*$")),
+    m_endifPattern(QLatin1String("^[\\s]*@[\\s]*endif.*$"))
+{
+    QTC_CHECK(m_ifPattern.isValid() && m_elsifPattern.isValid()
+              && m_elsePattern.isValid() && m_endifPattern.isValid());
+}
+
+void PreprocessContext::reset()
+{
+    m_sectionStack.clear();
+    // Add a default, enabled section.
+    m_sectionStack.push(PreprocessStackEntry(OtherSection, true, true));
+}
+
+// Determine type of line and return enumeration, cut out
+// expression for '@if/@elsif'.
+PreprocessorSection PreprocessContext::preprocessorLine(const QString &in,
+                                                        QString *ifExpression) const
+{
+    if (m_ifPattern.exactMatch(in)) {
+        *ifExpression = m_ifPattern.cap(2).trimmed();
+        return IfSection;
+    }
+    if (m_elsifPattern.exactMatch(in)) {
+        *ifExpression = m_elsifPattern.cap(2).trimmed();
+        return ElsifSection;
+    }
+
+    ifExpression->clear();
+
+    if (m_elsePattern.exactMatch(in))
+        return ElseSection;
+    if (m_endifPattern.exactMatch(in))
+        return EndifSection;
+    return OtherSection;
+}
+
+static inline QString msgEmptyStack(int line)
+{
+    return QString::fromLatin1("Unmatched '@endif' at line %1.").arg(line);
+}
+
+bool PreprocessContext::process(const QString &in, QString *out, QString *errorMessage)
+{
+    out->clear();
+    if (in.isEmpty())
+        return true;
+
+    out->reserve(in.size());
+    reset();
+
+    const QChar newLine = QLatin1Char('\n');
+    const QStringList lines = in.split(newLine, QString::KeepEmptyParts);
+    const int lineCount = lines.size();
+    for (int l = 0; l < lineCount; l++) {
+        // Check for element of the stack (be it dummy, else something is wrong).
+        if (m_sectionStack.isEmpty()) {
+            if (errorMessage)
+                *errorMessage = msgEmptyStack(l);
+            return false;
+        }
+    QString expression;
+        bool expressionValue = false;
+        PreprocessStackEntry &top = m_sectionStack.back();
+
+        switch (preprocessorLine(lines.at(l), &expression)) {
+        case IfSection:
+            // '@If': Push new section
+            if (top.condition) {
+                if (!TemplateEngine::evaluateBooleanJavaScriptExpression(m_scriptEngine, expression,
+                                                                         &expressionValue, errorMessage)) {
+                    if (errorMessage)
+                        *errorMessage = QString::fromLatin1("Error in @if at %1: %2")
+                            .arg(l + 1).arg(*errorMessage);
+                    return false;
+                }
+            }
+            m_sectionStack.push(PreprocessStackEntry(IfSection,
+                                                     top.condition, expressionValue, expressionValue));
+            break;
+        case ElsifSection: // '@elsif': Check condition.
+            if (top.section != IfSection && top.section != ElsifSection) {
+                if (errorMessage)
+                    *errorMessage = QString::fromLatin1("No preceding @if found for @elsif at %1")
+                        .arg(l + 1);
+                return false;
+            }
+            if (top.parentEnabled) {
+                if (!TemplateEngine::evaluateBooleanJavaScriptExpression(m_scriptEngine, expression,
+                                                                         &expressionValue, errorMessage)) {
+                    if (errorMessage)
+                        *errorMessage = QString::fromLatin1("Error in @elsif at %1: %2")
+                            .arg(l + 1).arg(*errorMessage);
+                    return false;
+                }
+            }
+            top.section = ElsifSection;
+            // ignore consecutive '@elsifs' once something matched
+            if (top.anyIfClauseMatched) {
+                top.condition = false;
+            } else {
+                if ( (top.condition = expressionValue) )
+                    top.anyIfClauseMatched = true;
+            }
+            break;
+        case ElseSection: // '@else': Check condition.
+            if (top.section != IfSection && top.section != ElsifSection) {
+                if (errorMessage)
+                    *errorMessage = QString::fromLatin1("No preceding @if/@elsif found for @else at %1")
+                        .arg(l + 1);
+                return false;
+            }
+            expressionValue = top.parentEnabled && !top.anyIfClauseMatched;
+            top.section = ElseSection;
+            top.condition = expressionValue;
+            break;
+        case EndifSection: // '@endif': Discard section.
+            m_sectionStack.pop();
+            break;
+        case OtherSection: // Rest: Append according to current condition.
+            if (top.condition) {
+                out->append(lines.at(l));
+                out->append(newLine);
+            }
+            break;
+        } // switch section
+
+    } // for lines
+    return true;
+}
+
+} // namespace Internal
+
+bool TemplateEngine::preprocessText(const QString &in, QString *out, QString *errorMessage)
+{
+    Internal::PreprocessContext context;
+    return context.process(in, out, errorMessage);
+}
+
+QString TemplateEngine::processText(MacroExpander *expander, const QString &input,
+                                    QString *errorMessage)
+{
+    if (errorMessage)
+        errorMessage->clear();
+
+    if (input.isEmpty())
+        return input;
+
+    // Recursively expand macros:
+    QString in = input;
+    QString oldIn;
+    for (int i = 0; i < 5 && in != oldIn; ++i) {
+        oldIn = in;
+        in = expander->expand(oldIn);
+    }
+
+    QString out;
+    if (!preprocessText(in, &out, errorMessage))
+        return QString();
+
+    // Expand \n, \t and handle line continuation:
+    QString result;
+    result.reserve(out.count());
+    bool isEscaped = false;
+    for (int i = 0; i < out.count(); ++i) {
+        const QChar c = out.at(i);
+
+        if (isEscaped) {
+            if (c == QLatin1Char('n'))
+                result.append(QLatin1Char('\n'));
+            else if (c == QLatin1Char('t'))
+                result.append(QLatin1Char('\t'));
+            else if (c != QLatin1Char('\n'))
+                result.append(c);
+            isEscaped = false;
+        } else {
+            if (c == QLatin1Char('\\'))
+                isEscaped = true;
+            else
+                result.append(c);
+        }
+    }
+    return result;
+}
+
+bool TemplateEngine::evaluateBooleanJavaScriptExpression(QJSEngine &engine,
+                                                         const QString &expression, bool *result,
+                                                         QString *errorMessage)
+{
+    if (errorMessage)
+        errorMessage->clear();
+    if (result)
+        *result = false;
+    const QJSValue value = engine.evaluate(expression);
+    if (value.isError()) {
+        if (errorMessage)
+            *errorMessage = QString::fromLatin1("Error in \"%1\": %2")
+                .arg(expression, value.toString());
+        return false;
+    }
+    // Try to convert to bool, be that an int or whatever.
+    if (value.isBool()) {
+        if (result)
+            *result = value.toBool();
+        return true;
+    }
+    if (value.isNumber()) {
+        if (result)
+            *result = !qFuzzyCompare(value.toNumber(), 0);
+        return true;
+    }
+    if (value.isString()) {
+        if (result)
+            *result = !value.toString().isEmpty();
+        return true;
+    }
+    if (errorMessage)
+        *errorMessage = QString::fromLatin1("Cannot convert result of \"%1\" (\"%2\"to bool.")
+            .arg(expression, value.toString());
+
+    return false;
+}
+
+} // namespace Utils
diff --git a/src/libs/utils/templateengine.h b/src/libs/utils/templateengine.h
new file mode 100644
index 00000000000..a277841ca09
--- /dev/null
+++ b/src/libs/utils/templateengine.h
@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef TEMPLATEENGINE_H
+#define TEMPLATEENGINE_H
+
+#include "utils_global.h"
+
+#include "macroexpander.h"
+
+#include <QString>
+
+QT_FORWARD_DECLARE_CLASS(QJSEngine);
+
+namespace Utils {
+
+class QTCREATOR_UTILS_EXPORT TemplateEngine {
+public:
+    static bool preprocessText(const QString &input, QString *output, QString *errorMessage);
+
+    static QString processText(MacroExpander *expander, const QString &input,
+                               QString *errorMessage);
+
+    static bool evaluateBooleanJavaScriptExpression(QJSEngine &engine, const QString &expression,
+                                                    bool *result, QString *errorMessage);
+};
+
+} // namespace Utils
+
+#endif // TEMPLATEENGINE_H
diff --git a/src/libs/utils/utils-lib.pri b/src/libs/utils/utils-lib.pri
index a4b7ed13818..bb66f7b5a5a 100644
--- a/src/libs/utils/utils-lib.pri
+++ b/src/libs/utils/utils-lib.pri
@@ -16,6 +16,7 @@ SOURCES += $$PWD/environment.cpp \
     $$PWD/shellcommandpage.cpp \
     $$PWD/settingsselector.cpp \
     $$PWD/stringutils.cpp \
+    $$PWD/templateengine.cpp \
     $$PWD/textfieldcheckbox.cpp \
     $$PWD/textfieldcombobox.cpp \
     $$PWD/filesearch.cpp \
@@ -107,6 +108,7 @@ HEADERS += \
     $$PWD/shellcommand.h \
     $$PWD/shellcommandpage.h \
     $$PWD/stringutils.h \
+    $$PWD/templateengine.h \
     $$PWD/textfieldcheckbox.h \
     $$PWD/textfieldcombobox.h \
     $$PWD/filesearch.h \
diff --git a/src/libs/utils/utils.pro b/src/libs/utils/utils.pro
index cb28e4ad43e..d69ff0ff44b 100644
--- a/src/libs/utils/utils.pro
+++ b/src/libs/utils/utils.pro
@@ -1,4 +1,4 @@
-QT += gui network
+QT += gui network qml
 
 include(../../qtcreatorlibrary.pri)
 include(utils-lib.pri)
diff --git a/src/libs/utils/utils.qbs b/src/libs/utils/utils.qbs
index 5b705a26bcf..c0e1879ee46 100644
--- a/src/libs/utils/utils.qbs
+++ b/src/libs/utils/utils.qbs
@@ -28,7 +28,7 @@ QtcLibrary {
         cpp.frameworks: ["Foundation"]
     }
 
-    Depends { name: "Qt"; submodules: ["widgets", "network", "script", "concurrent"] }
+    Depends { name: "Qt"; submodules: ["gui", "network", "qml"] }
     Depends { name: "app_version_header" }
 
     files: [