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#include "scriptdebugger.h"

#include "scriptbreakpointmanager.h"

#include <QtScript/QScriptEngine>

#include <QtScript/QScriptEngineAgent>

#include <QtScript/QScriptContextInfo>

#include <QtScript/QScriptValueIterator>

#include <QtCore/QTextStream>

#include <QtCore/QStack>

static QString safeValueToString(const QScriptValue &value)

{

    if (value.isObject())

        return QLatin1String("[object Object]");

    else

        return value.toString();

}

class ScriptInfo;

class ScriptBreakpointManager;

class ScriptDebuggerPrivate

    : public QScriptEngineAgent

{

    Q_DECLARE_PUBLIC(ScriptDebugger)

public:

    enum Mode {

        Run,

        StepInto,

        StepOver

    };

    ScriptDebuggerPrivate(QScriptEngine *engine);

    ~ScriptDebuggerPrivate();

    // QScriptEngineAgent interface

    void scriptLoad(qint64 id, const QString &program,

                    const QString &fileName, int lineNumber);

    void scriptUnload(qint64 id);

    void positionChange(qint64 scriptId,

                        int lineNumber, int columnNumber);

    void functionEntry(qint64 scriptId);

    void functionExit(qint64 scriptId,

                      const QScriptValue &returnValue);

    void exceptionThrow(qint64 scriptId,

                        const QScriptValue &exception, bool hasHandler);

    void interactive();

    bool executeCommand(const QString &command, const QStringList &args);

    void setMode(Mode mode);

    Mode mode() const;

    int frameCount() const;

    void setCurrentFrameIndex(int index);

    int currentFrameIndex() const;

    QScriptContext *frameContext(int index) const;

    QScriptContext *currentFrameContext() const;

    ScriptInfo *scriptInfo(QScriptContext *context) const;

    int listLineNumber() const;

    void setListLineNumber(int lineNumber);

    QString readLine();

    void output(const QString &text);

    void message(const QString &text);

    void errorMessage(const QString &text);

    // attributes

    QTextStream *m_defaultInputStream;

    QTextStream *m_defaultOutputStream;

    QTextStream *m_defaultErrorStream;

    QTextStream *m_inputStream;

    QTextStream *m_outputStream;

    QTextStream *m_errorStream;

    ScriptBreakpointManager *m_bpManager;

    Mode m_mode;

    QMap<qint64, ScriptInfo*> m_scripts;

    QMap<QScriptContext*, QStack<qint64> > m_contextProgramIds;

    QString m_lastInteractiveCommand;

    QString m_commandPrefix;

    int m_stepDepth;

    int m_currentFrameIndex;

    int m_listLineNumber;

    ScriptDebugger *q_ptr;

};

class ScriptInfo

{

public:

    ScriptInfo(const QString &code, const QString &fileName, int lineNumber)

        : m_code(code), m_fileName(fileName), m_lineNumber(lineNumber)

        { }

    inline QString code() const

        { return m_code; }

    inline QString fileName() const

        { return m_fileName; }

    inline int lineNumber() const

        { return m_lineNumber; }

    QString lineText(int lineNumber);

    QMap<int, int> m_lineOffsets;

private:

    int lineOffset(int lineNumber);

    QString m_code;

    QString m_fileName;

    int m_lineNumber;

};

int ScriptInfo::lineOffset(int lineNumber)

{

    QMap<int, int>::const_iterator it = m_lineOffsets.constFind(lineNumber);

    if (it != m_lineOffsets.constEnd())

        return it.value();

    int offset;

    it = m_lineOffsets.constFind(lineNumber - 1);

    if (it != m_lineOffsets.constEnd()) {

        offset = it.value();

        offset = m_code.indexOf(QLatin1Char('\n'), offset);

        if (offset != -1)

            ++offset;

        m_lineOffsets.insert(lineNumber, offset);

    } else {

        int index;

        it = m_lineOffsets.lowerBound(lineNumber);

        --it;

        if (it != m_lineOffsets.constBegin()) {

            index = it.key();

            offset = it.value();

        } else {

            index = m_lineNumber;

            offset = 0;

        }

        int j = index;

        for ( ; j < lineNumber; ++j) {

            m_lineOffsets.insert(j, offset);

            offset = m_code.indexOf(QLatin1Char('\n'), offset);

            if (offset == -1)

                break;

            ++offset;

        }

        m_lineOffsets.insert(j, offset);

    }

    return offset;

}

QString ScriptInfo::lineText(int lineNumber)

{

    int startOffset = lineOffset(lineNumber);

    if (startOffset == -1)

        return QString();

    int endOffset = lineOffset(lineNumber + 1);

    if (endOffset == -1)

        return m_code.mid(startOffset);

    else

        return m_code.mid(startOffset, endOffset - startOffset - 1);

}

ScriptDebuggerPrivate::ScriptDebuggerPrivate(QScriptEngine *engine)

    : QScriptEngineAgent(engine), m_mode(Run)

{

    m_commandPrefix = QLatin1String(".");

    m_bpManager = new ScriptBreakpointManager;

    m_defaultInputStream = new QTextStream(stdin);

    m_defaultOutputStream = new QTextStream(stdout);

    m_defaultErrorStream = new QTextStream(stderr);

    m_inputStream = m_defaultInputStream;

    m_outputStream = m_defaultOutputStream;

    m_errorStream = m_defaultErrorStream;

}

ScriptDebuggerPrivate::~ScriptDebuggerPrivate()

{

    delete m_defaultInputStream;

    delete m_defaultOutputStream;

    delete m_defaultErrorStream;

    delete m_bpManager;

    qDeleteAll(m_scripts);

}

QString ScriptDebuggerPrivate::readLine()

{

    return m_inputStream->readLine();

}

void ScriptDebuggerPrivate::output(const QString &text)

{

    *m_outputStream << text;

}

void ScriptDebuggerPrivate::message(const QString &text)

{

    *m_outputStream << text << endl;

    m_outputStream->flush();

}

void ScriptDebuggerPrivate::errorMessage(const QString &text)

{

    *m_errorStream << text << endl;

    m_errorStream->flush();

}

void ScriptDebuggerPrivate::setMode(Mode mode)

{

    m_mode = mode;

}

ScriptDebuggerPrivate::Mode ScriptDebuggerPrivate::mode() const

{

    return m_mode;

}

QScriptContext *ScriptDebuggerPrivate::frameContext(int index) const

{

    QScriptContext *ctx = engine()->currentContext();

    for (int i = 0; i < index; ++i) {

        ctx = ctx->parentContext();

        if (!ctx)

            break;

    }

    return ctx;

}

int ScriptDebuggerPrivate::currentFrameIndex() const

{

    return m_currentFrameIndex;

}

void ScriptDebuggerPrivate::setCurrentFrameIndex(int index)

{

    m_currentFrameIndex = index;

    m_listLineNumber = -1;

}

int ScriptDebuggerPrivate::listLineNumber() const

{

    return m_listLineNumber;

}

void ScriptDebuggerPrivate::setListLineNumber(int lineNumber)

{

    m_listLineNumber = lineNumber;

}

QScriptContext *ScriptDebuggerPrivate::currentFrameContext() const

{

    return frameContext(currentFrameIndex());

}

int ScriptDebuggerPrivate::frameCount() const

{

    int count = 0;

    QScriptContext *ctx = engine()->currentContext();

    while (ctx) {

        ++count;

        ctx = ctx->parentContext();

    }

    return count;

}

ScriptInfo *ScriptDebuggerPrivate::scriptInfo(QScriptContext *context) const

{

    QStack<qint64> pids = m_contextProgramIds.value(context);

    if (pids.isEmpty())

        return 0;

    return m_scripts.value(pids.top());

}

void ScriptDebuggerPrivate::interactive()

{

    setCurrentFrameIndex(0);

    QString qsdbgPrompt = QString::fromLatin1("(qsdbg) ");

    QString dotPrompt = QString::fromLatin1(".... ");

    QString prompt = qsdbgPrompt;

    QString code;

    forever {

         *m_outputStream << prompt;

        m_outputStream->flush();

        QString line = readLine();

        if (code.isEmpty() && (line.isEmpty() || line.startsWith(m_commandPrefix))) {

            if (line.isEmpty())

                line = m_lastInteractiveCommand;

            else

                m_lastInteractiveCommand = line;

            QStringList parts = line.split(QLatin1Char(' '), QString::SkipEmptyParts);

            if (!parts.isEmpty()) {

                QString command = parts.takeFirst().mid(1);

                if (executeCommand(command, parts))

                    break;

            }

        } else {

            if (line.isEmpty())

                continue;

            code += line;

            code += QLatin1Char('\n');

            if (line.trimmed().isEmpty()) {

                continue;

            } else if (! engine()->canEvaluate(code)) {

                prompt = dotPrompt;

            } else {

                setMode(Run);

                QScriptValue result = engine()->evaluate(code, QLatin1String("typein"));

                code.clear();

                prompt = qsdbgPrompt;

                if (! result.isUndefined()) {

                    errorMessage(result.toString());

                    engine()->clearExceptions();

                }

            }

        }

    }

}

bool ScriptDebuggerPrivate::executeCommand(const QString &command, const QStringList &args)

{

    if (command == QLatin1String("c")

        || command == QLatin1String("continue")) {

        setMode(Run);

        return true;

    } else if (command == QLatin1String("s")

               || command == QLatin1String("step")) {

        setMode(StepInto);

        return true;

    } else if (command == QLatin1String("n")

               || command == QLatin1String("next")) {

        setMode(StepOver);

        m_stepDepth = 0;

        return true;

    } else if (command == QLatin1String("f")

               || command == QLatin1String("frame")) {

        bool ok = false;

        int index = args.value(0).toInt(&ok);

        if (ok) {

            if (index < 0 || index >= frameCount()) {

                errorMessage("No such frame.");

            } else {

                setCurrentFrameIndex(index);

                QScriptContext *ctx = currentFrameContext();

                message(QString::fromLatin1("#%0  %1").arg(index).arg(ctx->toString()));

            }

        }

    } else if (command == QLatin1String("bt")

               || command == QLatin1String("backtrace")) {

        QScriptContext *ctx = engine()->currentContext();

        int index = -1;

        while (ctx) {

            ++index;

            QString line = ctx->toString();

            message(QString::fromLatin1("#%0  %1").arg(index).arg(line));

            ctx = ctx->parentContext();

        }

    } else if (command == QLatin1String("up")) {

        int index = currentFrameIndex() + 1;

        if (index == frameCount()) {

            errorMessage(QString::fromLatin1("Initial frame selected; you cannot go up."));

        } else {

            setCurrentFrameIndex(index);

            QScriptContext *ctx = currentFrameContext();

            message(QString::fromLatin1("#%0  %1").arg(index).arg(ctx->toString()));

        }

    } else if (command == QLatin1String("down")) {

        int index = currentFrameIndex() - 1;

        if (index < 0) {

            errorMessage(QString::fromLatin1("Bottom (innermost) frame selected; you cannot go down."));

        } else {

            setCurrentFrameIndex(index);

            QScriptContext *ctx = currentFrameContext();

            message(QString::fromLatin1("#%0  %1").arg(index).arg(ctx->toString()));

        }

    } else if (command == QLatin1String("b")

               || command == QLatin1String("break")) {

        QString str = args.value(0);

        int colonIndex = str.indexOf(QLatin1Char(':'));

        if (colonIndex != -1) {

            // filename:line form

            QString fileName = str.left(colonIndex);

            int lineNumber = str.mid(colonIndex+1).toInt();

            int id = m_bpManager->setBreakpoint(fileName, lineNumber);

            message(QString::fromLatin1("Breakpoint %0 at %1, line %2.").arg(id+1).arg(fileName).arg(lineNumber));

        } else {

            // function

            QScriptValue fun = engine()->globalObject().property(str);

            if (fun.isFunction()) {

                int id = m_bpManager->setBreakpoint(fun);

                message(QString::fromLatin1("Breakpoint %0 at %1().").arg(id+1).arg(str));

            }

        }

    } else if (command == QLatin1String("d")

               || command == QLatin1String("delete")) {

        int id = args.value(0).toInt() - 1;

        m_bpManager->removeBreakpoint(id);

    } else if (command == QLatin1String("disable")) {

        int id = args.value(0).toInt() - 1;

        m_bpManager->setBreakpointEnabled(id, false);

    } else if (command == QLatin1String("enable")) {

        int id = args.value(0).toInt() - 1;

        m_bpManager->setBreakpointEnabled(id, true);

    } else if (command == QLatin1String("list")) {

        QScriptContext *ctx = currentFrameContext();

        ScriptInfo *progInfo = scriptInfo(ctx);

        if (!progInfo) {

            errorMessage("No source text available for this frame.");

        } else {

            QScriptContextInfo ctxInfo(ctx);

            bool ok;

            int line = args.value(0).toInt(&ok);

            if (ok) {

                line = qMax(1, line - 5);

            } else {

                line = listLineNumber();

                if (line == -1)

                    line = qMax(progInfo->lineNumber(), ctxInfo.lineNumber() - 5);

            }

            for (int i = line; i < line + 10; ++i) {

                message(QString::fromLatin1("%0\t%1").arg(i).arg(progInfo->lineText(i)));

            }

            setListLineNumber(line + 10);

        }

    } else if (command == QLatin1String("info")) {

        if (args.size() < 1) {

        } else {

            QString what = args.value(0);

            if (what == QLatin1String("locals")) {

                QScriptValueIterator it(currentFrameContext()->activationObject());

                while (it.hasNext()) {

                    it.next();

                    QString line;

                    line.append(it.name());

                    line.append(QLatin1String(" = "));

                    line.append(safeValueToString(it.value()));

                    message(line);

                }

            }

        }

    } else if (command == QLatin1String("help")) {

        message("continue - continue execution\n"

                "step     - step into statement\n"

                "next     - step over statement\n"

                "list     - show where you are\n"

                "\n"

                "break    - set breakpoint\n"

                "delete   - remove breakpoint\n"

                "disable  - disable breakpoint\n"

                "enable   - enable breakpoint\n"

                "\n"

                "backtrace - show backtrace\n"

                "up       - one frame up\n"

                "down     - one frame down\n"

                "frame    - set frame\n"

                "\n"

                "info locals - show local variables");

    } else {

        errorMessage(QString::fromLatin1("Undefined command \"%0\". Try \"help\".")

                     .arg(command));

    }

    return false;

}