mustache.h

/*
  Copyright 2012, Robert Knight

  Redistribution and use in source and binary forms, with or without modification,
  are permitted provided that the following conditions are met:

    Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.

    Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
*/

#pragma once

#include <QtCore/QStack>
#include <QtCore/QString>
#include <QtCore/QVariant>

#if __cplusplus >= 201103L
#include <functional> /* for std::function */
#endif

namespace Mustache
{

class PartialResolver;
class Renderer;

class Context
{
public:
        explicit Context(PartialResolver* resolver = 0);
        virtual ~Context() {}

        virtual QString stringValue(const QString& key) const = 0;

        virtual bool isFalse(const QString& key) const = 0;

        virtual int listCount(const QString& key) const = 0;

        virtual void push(const QString& key, int index = -1) = 0;

        virtual void pop() = 0;

        QString partialValue(const QString& key) const;

        PartialResolver* partialResolver() const;

        virtual bool canEval(const QString& key) const;

        virtual QString eval(const QString& key, const QString& _template, Renderer* renderer);

private:
        PartialResolver* m_partialResolver;
};

class QtVariantContext : public Context
{
public:
#if __cplusplus >= 201103L
        typedef std::function<QString(const QString&, Mustache::Renderer*, Mustache::Context*)> fn_t;
#else
        typedef QString (*fn_t)(const QString&, Mustache::Renderer*, Mustache::Context*);
#endif
        explicit QtVariantContext(const QVariant& root, PartialResolver* resolver = 0);

        virtual QString stringValue(const QString& key) const;
        virtual bool isFalse(const QString& key) const;
        virtual int listCount(const QString& key) const;
        virtual void push(const QString& key, int index = -1);
        virtual void pop();
        virtual bool canEval(const QString& key) const;
        virtual QString eval(const QString& key, const QString& _template, Mustache::Renderer* renderer);

private:
        QVariant value(const QString& key) const;

        QStack<QVariant> m_contextStack;
};

class PartialResolver
{
public:
        virtual ~PartialResolver() {}

        virtual QString getPartial(const QString& name) = 0;
};

class PartialMap : public PartialResolver
{
public:
        explicit PartialMap(const QHash<QString,QString>& partials);

        virtual QString getPartial(const QString& name);

private:
        QHash<QString, QString> m_partials;
};

class PartialFileLoader : public PartialResolver
{
public:
        explicit PartialFileLoader(const QString& basePath);

        virtual QString getPartial(const QString& name);

private:
        QString m_basePath;
        QHash<QString, QString> m_cache;
};

struct Tag
{
        enum Type
        {
                Null,
                Value, 
                SectionStart, 
                InvertedSectionStart, 
                SectionEnd, 
                Partial, 
                Comment, 
                SetDelimiter 
        };

        enum EscapeMode
        {
                Escape,
                Unescape,
                Raw
        };

        Tag()
                : type(Null)
                , start(0)
                , end(0)
                , escapeMode(Escape)
        {}

        Type type;
        QString key;
        int start;
        int end;
        EscapeMode escapeMode;
};

class Renderer
{
public:
        Renderer();

        QString render(const QString& _template, Context* context);

        QString error() const;

        int errorPos() const;

        QString errorPartial() const;

        void setTagMarkers(const QString& startMarker, const QString& endMarker);

private:
        QString render(const QString& _template, int startPos, int endPos, Context* context);

        Tag findTag(const QString& content, int pos, int endPos);
        Tag findEndTag(const QString& content, const Tag& startTag, int endPos);
        void setError(const QString& error, int pos);

        void readSetDelimiter(const QString& content, int pos, int endPos);
        static QString readTagName(const QString& content, int pos, int endPos);

        static void expandTag(Tag& tag, const QString& content);

        QStack<QString> m_partialStack;
        QString m_error;
        int m_errorPos;
        QString m_errorPartial;

        QString m_tagStartMarker;
        QString m_tagEndMarker;

        QString m_defaultTagStartMarker;
        QString m_defaultTagEndMarker;
};

QString renderTemplate(const QString& templateString, const QVariantHash& args);

};

Q_DECLARE_METATYPE(Mustache::QtVariantContext::fn_t)