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#pragma once
#include <string>
#include <vector>
#include "json.h"
namespace crow
{
namespace mustache
{
using context = json::wvalue;
class invalid_template_exception : public std::exception
{
public:
invalid_template_exception(const std::string& msg)
: msg("crow::mustache error: " + msg)
{
}
virtual const char* what() const throw()
{
return msg.c_str();
}
std::string msg;
};
enum class ActionType
{
Ignore,
Tag,
UnescapeTag,
OpenBlock,
CloseBlock,
ElseBlock,
Partial,
};
struct Action
{
int start;
int end;
int pos;
ActionType t;
Action(ActionType t, int start, int end, int pos = 0)
: start(start), end(end), pos(pos), t(t)
{}
};
class template_t
{
public:
template_t(std::string body)
: body_(std::move(body))
{
// {{ {{# {{/ {{^ {{! {{> {{=
parse();
}
std::string render(context& ctx)
{
std::vector<context*> stack;
stack.emplace_back(&ctx);
auto tag_name = [&](const Action& action)
{
return body_.substr(action.start, action.end - action.start);
};
auto find_context = [&](const std::string& name)->std::pair<bool, context&>
{
for(auto it = stack.rbegin(); it != stack.rend(); ++it)
{
std::cerr << "finding " << name << " on " << (int)(*it)->t() << std::endl;
if ((*it)->t() == json::type::Object)
{
for(auto jt = (*it)->o->begin(); jt != (*it)->o->end(); ++jt)
{
std::cerr << '\t' << jt->first << ' ' << json::dump(jt->second) << std::endl;
}
if ((*it)->count(name))
return {true, (**it)[name]};
}
}
static json::wvalue empty_str;
empty_str = "";
return {false, empty_str};
};
int current = 0;
std::string ret;
while(current < fragments_.size())
{
auto& fragment = fragments_[current];
auto& action = actions_[current];
ret += body_.substr(fragment.first, fragment.second-fragment.first);
switch(action.t)
{
case ActionType::Ignore:
// do nothing
break;
case ActionType::Tag:
{
auto optional_ctx = find_context(tag_name(action));
auto& ctx = optional_ctx.second;
switch(ctx.t())
{
case json::type::Number:
ret += json::dump(ctx);
break;
case json::type::String:
ret += ctx.s;
break;
default:
throw std::runtime_error("not implemented tag type" + boost::lexical_cast<std::string>((int)ctx.t()));
}
}
break;
case ActionType::OpenBlock:
{
std::cerr << tag_name(action) << std::endl;
auto optional_ctx = find_context(tag_name(action));
std::cerr << optional_ctx.first << std::endl;
if (!optional_ctx.first)
current = action.pos;
auto& ctx = optional_ctx.second;
if (ctx.t() == json::type::Null || ctx.t() == json::type::False)
current = action.pos;
stack.push_back(&ctx);
break;
}
case ActionType::CloseBlock:
stack.pop_back();
break;
default:
throw std::runtime_error("not implemented " + boost::lexical_cast<std::string>((int)action.t));
}
current++;
}
return ret;
}
private:
void parse()
{
std::string tag_open = "{{";
std::string tag_close = "}}";
std::vector<int> blockPositions;
size_t current = 0;
while(1)
{
size_t idx = body_.find(tag_open, current);
if (idx == body_.npos)
{
fragments_.emplace_back(current, body_.size());
actions_.emplace_back(ActionType::Ignore, 0, 0);
break;
}
fragments_.emplace_back(current, idx);
idx += tag_open.size();
size_t endIdx = body_.find(tag_close, idx);
if (endIdx == idx)
{
throw invalid_template_exception("empty tag is not allowed");
}
if (endIdx == body_.npos)
{
// error, no matching tag
throw invalid_template_exception("not matched opening tag");
}
current = endIdx + tag_close.size();
switch(body_[idx])
{
case '#':
idx++;
blockPositions.emplace_back(actions_.size());
actions_.emplace_back(ActionType::OpenBlock, idx, endIdx);
break;
case '/':
idx++;
{
auto& matched = actions_[blockPositions.back()];
if (body_.compare(idx, endIdx-idx,
body_, matched.start, matched.end - matched.start) != 0)
{
throw invalid_template_exception("not matched {{# {{/ pair: " +
body_.substr(matched.start, matched.end - matched.start) + ", " +
body_.substr(idx, endIdx-idx));
}
matched.pos = actions_.size();
}
actions_.emplace_back(ActionType::CloseBlock, idx, endIdx, blockPositions.back());
blockPositions.pop_back();
break;
case '^':
blockPositions.emplace_back(actions_.size());
actions_.emplace_back(ActionType::ElseBlock, idx+1, endIdx);
break;
case '!':
// do nothing action
actions_.emplace_back(ActionType::Ignore, idx+1, endIdx);
break;
case '>': // partial
actions_.emplace_back(ActionType::Partial, idx+1, endIdx);
throw invalid_template_exception("{{>: partial not implemented: " + body_.substr(idx+1, endIdx-idx-1));
break;
case '{':
if (tag_open != "{{" || tag_close != "}}")
throw invalid_template_exception("cannot use triple mustache when delimiter changed");
idx ++;
if (body_[endIdx+2] != '}')
{
throw invalid_template_exception("{{{: }}} not matched");
}
actions_.emplace_back(ActionType::UnescapeTag, idx, endIdx);
current++;
break;
case '&':
idx ++;
actions_.emplace_back(ActionType::UnescapeTag, idx, endIdx);
break;
case '=':
// tag itself is no-op
idx ++;
actions_.emplace_back(ActionType::Ignore, idx, endIdx);
endIdx --;
if (body_[endIdx] != '=')
throw invalid_template_exception("{{=: not matching = tag: "+body_.substr(idx, endIdx-idx));
endIdx --;
while(body_[idx] == ' ') idx++;
while(body_[endIdx] == ' ') endIdx--;
endIdx++;
{
bool succeeded = false;
for(size_t i = idx; i < endIdx; i++)
{
if (body_[i] == ' ')
{
tag_open = body_.substr(idx, i-idx);
while(body_[i] == ' ') i++;
tag_close = body_.substr(i, endIdx-i);
if (tag_open.empty())
throw invalid_template_exception("{{=: empty open tag");
if (tag_close.empty())
throw invalid_template_exception("{{=: empty close tag");
if (tag_close.find(" ") != tag_close.npos)
throw invalid_template_exception("{{=: invalid open/close tag: "+tag_open+" " + tag_close);
succeeded = true;
break;
}
}
if (!succeeded)
throw invalid_template_exception("{{=: cannot find space between new open/close tags");
}
break;
default:
// normal tag case;
actions_.emplace_back(ActionType::Tag, idx, endIdx);
break;
}
}
}
std::vector<std::pair<int,int>> fragments_;
std::vector<Action> actions_;
std::string body_;
};
template_t compile(const std::string& body)
{
return template_t(body);
}
}
}
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