File mustache.hpp of Package libkiwix
/*
* Boost Software License - Version 1.0
*
* Mustache v4.1
* Copyright 2015-2020 Kevin Wojniak
*
* Permission is hereby granted, free of charge, to any person or organization
* obtaining a copy of the software and accompanying documentation covered by
* this license (the "Software") to use, reproduce, display, distribute,
* execute, and transmit the Software, and to prepare derivative works of the
* Software, and to permit third-parties to whom the Software is furnished to
* do so, all subject to the following:
*
* The copyright notices in the Software and this entire statement, including
* the above license grant, this restriction and the following disclaimer,
* must be included in all copies of the Software, in whole or in part, and
* all derivative works of the Software, unless such copies or derivative
* works are solely in the form of machine-executable object code generated by
* a source language processor.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
* SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
* FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef KAINJOW_MUSTACHE_HPP
#define KAINJOW_MUSTACHE_HPP
#include <cassert>
#include <cctype>
#include <functional>
#include <iostream>
#include <memory>
#include <sstream>
#include <unordered_map>
#include <vector>
namespace kainjow {
namespace mustache {
template <typename string_type>
string_type trim(const string_type& s) {
auto it = s.begin();
while (it != s.end() && std::isspace(*it)) {
it++;
}
auto rit = s.rbegin();
while (rit.base() != it && std::isspace(*rit)) {
rit++;
}
return {it, rit.base()};
}
template <typename string_type>
string_type html_escape(const string_type& s) {
string_type ret;
ret.reserve(s.size()*2);
for (const auto ch : s) {
switch (ch) {
case '&':
ret.append({'&','a','m','p',';'});
break;
case '<':
ret.append({'&','l','t',';'});
break;
case '>':
ret.append({'&','g','t',';'});
break;
case '\"':
ret.append({'&','q','u','o','t',';'});
break;
case '\'':
ret.append({'&','a','p','o','s',';'});
break;
default:
ret.append(1, ch);
break;
}
}
return ret;
}
template <typename string_type>
std::vector<string_type> split(const string_type& s, typename string_type::value_type delim) {
std::vector<string_type> elems;
std::basic_stringstream<typename string_type::value_type> ss(s);
string_type item;
while (std::getline(ss, item, delim)) {
elems.push_back(item);
}
return elems;
}
template <typename string_type>
class basic_renderer {
public:
using type1 = std::function<string_type(const string_type&)>;
using type2 = std::function<string_type(const string_type&, bool escaped)>;
string_type operator()(const string_type& text) const {
return type1_(text);
}
string_type operator()(const string_type& text, bool escaped) const {
return type2_(text, escaped);
}
private:
basic_renderer(const type1& t1, const type2& t2)
: type1_(t1)
, type2_(t2)
{}
const type1& type1_;
const type2& type2_;
template <typename StringType>
friend class basic_mustache;
};
template <typename string_type>
class basic_lambda_t {
public:
using type1 = std::function<string_type(const string_type&)>;
using type2 = std::function<string_type(const string_type&, const basic_renderer<string_type>& render)>;
basic_lambda_t(const type1& t) : type1_(new type1(t)) {}
basic_lambda_t(const type2& t) : type2_(new type2(t)) {}
bool is_type1() const { return static_cast<bool>(type1_); }
bool is_type2() const { return static_cast<bool>(type2_); }
const type1& type1_value() const { return *type1_; }
const type2& type2_value() const { return *type2_; }
// Copying
basic_lambda_t(const basic_lambda_t& l) {
if (l.type1_) {
type1_.reset(new type1(*l.type1_));
} else if (l.type2_) {
type2_.reset(new type2(*l.type2_));
}
}
string_type operator()(const string_type& text) const {
return (*type1_)(text);
}
string_type operator()(const string_type& text, const basic_renderer<string_type>& render) const {
return (*type2_)(text, render);
}
private:
std::unique_ptr<type1> type1_;
std::unique_ptr<type2> type2_;
};
template <typename string_type>
class basic_data;
template <typename string_type>
using basic_object = std::unordered_map<string_type, basic_data<string_type>>;
template <typename string_type>
using basic_list = std::vector<basic_data<string_type>>;
template <typename string_type>
using basic_partial = std::function<string_type()>;
template <typename string_type>
using basic_lambda = typename basic_lambda_t<string_type>::type1;
template <typename string_type>
using basic_lambda2 = typename basic_lambda_t<string_type>::type2;
template <typename string_type>
class basic_data {
public:
enum class type {
object,
string,
list,
bool_true,
bool_false,
partial,
lambda,
lambda2,
invalid,
};
// Construction
basic_data() : basic_data(type::object) {
}
basic_data(const string_type& string) : type_{type::string} {
str_.reset(new string_type(string));
}
basic_data(const typename string_type::value_type* string) : type_{type::string} {
str_.reset(new string_type(string));
}
basic_data(const basic_object<string_type>& obj) : type_{type::object} {
obj_.reset(new basic_object<string_type>(obj));
}
basic_data(const basic_list<string_type>& l) : type_{type::list} {
list_.reset(new basic_list<string_type>(l));
}
basic_data(type t) : type_{t} {
switch (type_) {
case type::object:
obj_.reset(new basic_object<string_type>);
break;
case type::string:
str_.reset(new string_type);
break;
case type::list:
list_.reset(new basic_list<string_type>);
break;
default:
break;
}
}
basic_data(const string_type& name, const basic_data& var) : basic_data{} {
set(name, var);
}
basic_data(const basic_partial<string_type>& p) : type_{type::partial} {
partial_.reset(new basic_partial<string_type>(p));
}
basic_data(const basic_lambda<string_type>& l) : type_{type::lambda} {
lambda_.reset(new basic_lambda_t<string_type>(l));
}
basic_data(const basic_lambda2<string_type>& l) : type_{type::lambda2} {
lambda_.reset(new basic_lambda_t<string_type>(l));
}
basic_data(const basic_lambda_t<string_type>& l) {
if (l.is_type1()) {
type_ = type::lambda;
} else if (l.is_type2()) {
type_ = type::lambda2;
}
lambda_.reset(new basic_lambda_t<string_type>(l));
}
basic_data(bool b) : type_{b ? type::bool_true : type::bool_false} {
}
// Copying
basic_data(const basic_data& dat) : type_(dat.type_) {
if (dat.obj_) {
obj_.reset(new basic_object<string_type>(*dat.obj_));
} else if (dat.str_) {
str_.reset(new string_type(*dat.str_));
} else if (dat.list_) {
list_.reset(new basic_list<string_type>(*dat.list_));
} else if (dat.partial_) {
partial_.reset(new basic_partial<string_type>(*dat.partial_));
} else if (dat.lambda_) {
lambda_.reset(new basic_lambda_t<string_type>(*dat.lambda_));
}
}
// Move
basic_data(basic_data&& dat) : type_{dat.type_} {
if (dat.obj_) {
obj_ = std::move(dat.obj_);
} else if (dat.str_) {
str_ = std::move(dat.str_);
} else if (dat.list_) {
list_ = std::move(dat.list_);
} else if (dat.partial_) {
partial_ = std::move(dat.partial_);
} else if (dat.lambda_) {
lambda_ = std::move(dat.lambda_);
}
dat.type_ = type::invalid;
}
basic_data& operator= (basic_data&& dat) {
if (this != &dat) {
obj_.reset();
str_.reset();
list_.reset();
partial_.reset();
lambda_.reset();
if (dat.obj_) {
obj_ = std::move(dat.obj_);
} else if (dat.str_) {
str_ = std::move(dat.str_);
} else if (dat.list_) {
list_ = std::move(dat.list_);
} else if (dat.partial_) {
partial_ = std::move(dat.partial_);
} else if (dat.lambda_) {
lambda_ = std::move(dat.lambda_);
}
type_ = dat.type_;
dat.type_ = type::invalid;
}
return *this;
}
// Type info
bool is_object() const {
return type_ == type::object;
}
bool is_string() const {
return type_ == type::string;
}
bool is_list() const {
return type_ == type::list;
}
bool is_bool() const {
return is_true() || is_false();
}
bool is_true() const {
return type_ == type::bool_true;
}
bool is_false() const {
return type_ == type::bool_false;
}
bool is_partial() const {
return type_ == type::partial;
}
bool is_lambda() const {
return type_ == type::lambda;
}
bool is_lambda2() const {
return type_ == type::lambda2;
}
bool is_invalid() const {
return type_ == type::invalid;
}
// Object data
bool is_empty_object() const {
return is_object() && obj_->empty();
}
bool is_non_empty_object() const {
return is_object() && !obj_->empty();
}
void set(const string_type& name, const basic_data& var) {
if (is_object()) {
auto it = obj_->find(name);
if (it != obj_->end()) {
obj_->erase(it);
}
obj_->insert(std::pair<string_type,basic_data>{name, var});
}
}
const basic_data* get(const string_type& name) const {
if (!is_object()) {
return nullptr;
}
const auto& it = obj_->find(name);
if (it == obj_->end()) {
return nullptr;
}
return &it->second;
}
// List data
void push_back(const basic_data& var) {
if (is_list()) {
list_->push_back(var);
}
}
const basic_list<string_type>& list_value() const {
return *list_;
}
bool is_empty_list() const {
return is_list() && list_->empty();
}
bool is_non_empty_list() const {
return is_list() && !list_->empty();
}
basic_data& operator<< (const basic_data& data) {
push_back(data);
return *this;
}
// String data
const string_type& string_value() const {
return *str_;
}
basic_data& operator[] (const string_type& key) {
return (*obj_)[key];
}
const basic_partial<string_type>& partial_value() const {
return (*partial_);
}
const basic_lambda<string_type>& lambda_value() const {
return lambda_->type1_value();
}
const basic_lambda2<string_type>& lambda2_value() const {
return lambda_->type2_value();
}
private:
type type_;
std::unique_ptr<basic_object<string_type>> obj_;
std::unique_ptr<string_type> str_;
std::unique_ptr<basic_list<string_type>> list_;
std::unique_ptr<basic_partial<string_type>> partial_;
std::unique_ptr<basic_lambda_t<string_type>> lambda_;
};
template <typename string_type>
class delimiter_set {
public:
string_type begin;
string_type end;
delimiter_set()
: begin(default_begin)
, end(default_end)
{}
bool is_default() const { return begin == default_begin && end == default_end; }
static const string_type default_begin;
static const string_type default_end;
};
template <typename string_type>
const string_type delimiter_set<string_type>::default_begin(2, '{');
template <typename string_type>
const string_type delimiter_set<string_type>::default_end(2, '}');
template <typename string_type>
class basic_context {
public:
virtual ~basic_context() = default;
virtual void push(const basic_data<string_type>* data) = 0;
virtual void pop() = 0;
virtual const basic_data<string_type>* get(const string_type& name) const = 0;
virtual const basic_data<string_type>* get_partial(const string_type& name) const = 0;
};
template <typename string_type>
class context : public basic_context<string_type> {
public:
context(const basic_data<string_type>* data) {
push(data);
}
context() {
}
virtual void push(const basic_data<string_type>* data) override {
items_.insert(items_.begin(), data);
}
virtual void pop() override {
items_.erase(items_.begin());
}
virtual const basic_data<string_type>* get(const string_type& name) const override {
// process {{.}} name
if (name.size() == 1 && name.at(0) == '.') {
return items_.front();
}
if (name.find('.') == string_type::npos) {
// process normal name without having to split which is slower
for (const auto& item : items_) {
const auto var = item->get(name);
if (var) {
return var;
}
}
return nullptr;
}
// process x.y-like name
const auto names = split(name, '.');
for (const auto& item : items_) {
auto var = item;
for (const auto& n : names) {
var = var->get(n);
if (!var) {
break;
}
}
if (var) {
return var;
}
}
return nullptr;
}
virtual const basic_data<string_type>* get_partial(const string_type& name) const override {
for (const auto& item : items_) {
const auto var = item->get(name);
if (var) {
return var;
}
}
return nullptr;
}
context(const context&) = delete;
context& operator= (const context&) = delete;
private:
std::vector<const basic_data<string_type>*> items_;
};
template <typename string_type>
class line_buffer_state {
public:
string_type data;
bool contained_section_tag = false;
bool is_empty_or_contains_only_whitespace() const {
for (const auto ch : data) {
// don't look at newlines
if (ch != ' ' && ch != '\t') {
return false;
}
}
return true;
}
void clear() {
data.clear();
contained_section_tag = false;
}
};
template <typename string_type>
class context_internal {
public:
basic_context<string_type>& ctx;
delimiter_set<string_type> delim_set;
line_buffer_state<string_type> line_buffer;
context_internal(basic_context<string_type>& a_ctx)
: ctx(a_ctx)
{
}
};
enum class tag_type {
text,
variable,
unescaped_variable,
section_begin,
section_end,
section_begin_inverted,
comment,
partial,
set_delimiter,
};
template <typename string_type>
class mstch_tag /* gcc doesn't allow "tag tag;" so rename the class :( */ {
public:
string_type name;
tag_type type = tag_type::text;
std::shared_ptr<string_type> section_text;
std::shared_ptr<delimiter_set<string_type>> delim_set;
bool is_section_begin() const {
return type == tag_type::section_begin || type == tag_type::section_begin_inverted;
}
bool is_section_end() const {
return type == tag_type::section_end;
}
};
template <typename string_type>
class context_pusher {
public:
context_pusher(context_internal<string_type>& ctx, const basic_data<string_type>* data)
: ctx_(ctx)
{
ctx.ctx.push(data);
}
~context_pusher() {
ctx_.ctx.pop();
}
context_pusher(const context_pusher&) = delete;
context_pusher& operator= (const context_pusher&) = delete;
private:
context_internal<string_type>& ctx_;
};
template <typename string_type>
class component {
private:
using string_size_type = typename string_type::size_type;
public:
string_type text;
mstch_tag<string_type> tag;
std::vector<component> children;
string_size_type position = string_type::npos;
enum class walk_control {
walk, // "continue" is reserved :/
stop,
skip,
};
using walk_callback = std::function<walk_control(component&)>;
component() {}
component(const string_type& t, string_size_type p) : text(t), position(p) {}
bool is_text() const {
return tag.type == tag_type::text;
}
bool is_newline() const {
return is_text() && ((text.size() == 2 && text[0] == '\r' && text[1] == '\n') ||
(text.size() == 1 && (text[0] == '\n' || text[0] == '\r')));
}
bool is_non_newline_whitespace() const {
return is_text() && !is_newline() && text.size() == 1 && (text[0] == ' ' || text[0] == '\t');
}
void walk_children(const walk_callback& callback) {
for (auto& child : children) {
if (child.walk(callback) != walk_control::walk) {
break;
}
}
}
private:
walk_control walk(const walk_callback& callback) {
walk_control control{callback(*this)};
if (control == walk_control::stop) {
return control;
} else if (control == walk_control::skip) {
return walk_control::walk;
}
for (auto& child : children) {
control = child.walk(callback);
if (control == walk_control::stop) {
return control;
}
}
return control;
}
};
template <typename string_type>
class parser {
public:
parser(const string_type& input, context_internal<string_type>& ctx, component<string_type>& root_component, string_type& error_message)
{
parse(input, ctx, root_component, error_message);
}
private:
void parse(const string_type& input, context_internal<string_type>& ctx, component<string_type>& root_component, string_type& error_message) const {
using string_size_type = typename string_type::size_type;
using streamstring = std::basic_ostringstream<typename string_type::value_type>;
const string_type brace_delimiter_end_unescaped(3, '}');
const string_size_type input_size{input.size()};
bool current_delimiter_is_brace{ctx.delim_set.is_default()};
std::vector<component<string_type>*> sections{&root_component};
std::vector<string_size_type> section_starts;
string_type current_text;
string_size_type current_text_position = -1;
current_text.reserve(input_size);
const auto process_current_text = [¤t_text, ¤t_text_position, §ions]() {
if (!current_text.empty()) {
const component<string_type> comp{current_text, current_text_position};
sections.back()->children.push_back(comp);
current_text.clear();
current_text_position = -1;
}
};
const std::vector<string_type> whitespace{
string_type(1, '\r') + string_type(1, '\n'),
string_type(1, '\n'),
string_type(1, '\r'),
string_type(1, ' '),
string_type(1, '\t'),
};
for (string_size_type input_position = 0; input_position != input_size;) {
bool parse_tag = false;
if (input.compare(input_position, ctx.delim_set.begin.size(), ctx.delim_set.begin) == 0) {
process_current_text();
// Tag start delimiter
parse_tag = true;
} else {
bool parsed_whitespace = false;
for (const auto& whitespace_text : whitespace) {
if (input.compare(input_position, whitespace_text.size(), whitespace_text) == 0) {
process_current_text();
const component<string_type> comp{whitespace_text, input_position};
sections.back()->children.push_back(comp);
input_position += whitespace_text.size();
parsed_whitespace = true;
break;
}
}
if (!parsed_whitespace) {
if (current_text.empty()) {
current_text_position = input_position;
}
current_text.append(1, input[input_position]);
input_position++;
}
}
if (!parse_tag) {
continue;
}
// Find the next tag start delimiter
const string_size_type tag_location_start = input_position;
// Find the next tag end delimiter
string_size_type tag_contents_location{tag_location_start + ctx.delim_set.begin.size()};
const bool tag_is_unescaped_var{current_delimiter_is_brace && tag_location_start != (input_size - 2) && input.at(tag_contents_location) == ctx.delim_set.begin.at(0)};
const string_type& current_tag_delimiter_end{tag_is_unescaped_var ? brace_delimiter_end_unescaped : ctx.delim_set.end};
const auto current_tag_delimiter_end_size = current_tag_delimiter_end.size();
if (tag_is_unescaped_var) {
++tag_contents_location;
}
const string_size_type tag_location_end{input.find(current_tag_delimiter_end, tag_contents_location)};
if (tag_location_end == string_type::npos) {
streamstring ss;
ss << "Unclosed tag at " << tag_location_start;
error_message.assign(ss.str());
return;
}
// Parse tag
const string_type tag_contents{trim(string_type{input, tag_contents_location, tag_location_end - tag_contents_location})};
component<string_type> comp;
if (!tag_contents.empty() && tag_contents[0] == '=') {
if (!parse_set_delimiter_tag(tag_contents, ctx.delim_set)) {
streamstring ss;
ss << "Invalid set delimiter tag at " << tag_location_start;
error_message.assign(ss.str());
return;
}
current_delimiter_is_brace = ctx.delim_set.is_default();
comp.tag.type = tag_type::set_delimiter;
comp.tag.delim_set.reset(new delimiter_set<string_type>(ctx.delim_set));
}
if (comp.tag.type != tag_type::set_delimiter) {
parse_tag_contents(tag_is_unescaped_var, tag_contents, comp.tag);
}
comp.position = tag_location_start;
sections.back()->children.push_back(comp);
// Start next search after this tag
input_position = tag_location_end + current_tag_delimiter_end_size;
// Push or pop sections
if (comp.tag.is_section_begin()) {
sections.push_back(§ions.back()->children.back());
section_starts.push_back(input_position);
} else if (comp.tag.is_section_end()) {
if (sections.size() == 1) {
streamstring ss;
ss << "Unopened section \"" << comp.tag.name << "\" at " << comp.position;
error_message.assign(ss.str());
return;
}
sections.back()->tag.section_text.reset(new string_type(input.substr(section_starts.back(), tag_location_start - section_starts.back())));
sections.pop_back();
section_starts.pop_back();
}
}
process_current_text();
// Check for sections without an ending tag
root_component.walk_children([&error_message](component<string_type>& comp) -> typename component<string_type>::walk_control {
if (!comp.tag.is_section_begin()) {
return component<string_type>::walk_control::walk;
}
if (comp.children.empty() || !comp.children.back().tag.is_section_end() || comp.children.back().tag.name != comp.tag.name) {
streamstring ss;
ss << "Unclosed section \"" << comp.tag.name << "\" at " << comp.position;
error_message.assign(ss.str());
return component<string_type>::walk_control::stop;
}
comp.children.pop_back(); // remove now useless end section component
return component<string_type>::walk_control::walk;
});
if (!error_message.empty()) {
return;
}
}
bool is_set_delimiter_valid(const string_type& delimiter) const {
// "Custom delimiters may not contain whitespace or the equals sign."
for (const auto ch : delimiter) {
if (ch == '=' || std::isspace(ch)) {
return false;
}
}
return true;
}
bool parse_set_delimiter_tag(const string_type& contents, delimiter_set<string_type>& delimiter_set) const {
// Smallest legal tag is "=X X="
if (contents.size() < 5) {
return false;
}
if (contents.back() != '=') {
return false;
}
const auto contents_substr = trim(contents.substr(1, contents.size() - 2));
const auto spacepos = contents_substr.find(' ');
if (spacepos == string_type::npos) {
return false;
}
const auto nonspace = contents_substr.find_first_not_of(' ', spacepos + 1);
assert(nonspace != string_type::npos);
const string_type begin = contents_substr.substr(0, spacepos);
const string_type end = contents_substr.substr(nonspace, contents_substr.size() - nonspace);
if (!is_set_delimiter_valid(begin) || !is_set_delimiter_valid(end)) {
return false;
}
delimiter_set.begin = begin;
delimiter_set.end = end;
return true;
}
void parse_tag_contents(bool is_unescaped_var, const string_type& contents, mstch_tag<string_type>& tag) const {
if (is_unescaped_var) {
tag.type = tag_type::unescaped_variable;
tag.name = contents;
} else if (contents.empty()) {
tag.type = tag_type::variable;
tag.name.clear();
} else {
switch (contents.at(0)) {
case '#':
tag.type = tag_type::section_begin;
break;
case '^':
tag.type = tag_type::section_begin_inverted;
break;
case '/':
tag.type = tag_type::section_end;
break;
case '>':
tag.type = tag_type::partial;
break;
case '&':
tag.type = tag_type::unescaped_variable;
break;
case '!':
tag.type = tag_type::comment;
break;
default:
tag.type = tag_type::variable;
break;
}
if (tag.type == tag_type::variable) {
tag.name = contents;
} else {
string_type name{contents};
name.erase(name.begin());
tag.name = trim(name);
}
}
}
};
template <typename StringType>
class basic_mustache {
public:
using string_type = StringType;
basic_mustache(const string_type& input)
: basic_mustache() {
context<string_type> ctx;
context_internal<string_type> context{ctx};
parser<string_type> parser{input, context, root_component_, error_message_};
}
bool is_valid() const {
return error_message_.empty();
}
const string_type& error_message() const {
return error_message_;
}
using escape_handler = std::function<string_type(const string_type&)>;
void set_custom_escape(const escape_handler& escape_fn) {
escape_ = escape_fn;
}
template <typename stream_type>
stream_type& render(const basic_data<string_type>& data, stream_type& stream) {
render(data, [&stream](const string_type& str) {
stream << str;
});
return stream;
}
string_type render(const basic_data<string_type>& data) {
std::basic_ostringstream<typename string_type::value_type> ss;
return render(data, ss).str();
}
template <typename stream_type>
stream_type& render(basic_context<string_type>& ctx, stream_type& stream) {
context_internal<string_type> context{ctx};
render([&stream](const string_type& str) {
stream << str;
}, context);
return stream;
}
string_type render(basic_context<string_type>& ctx) {
std::basic_ostringstream<typename string_type::value_type> ss;
return render(ctx, ss).str();
}
using render_handler = std::function<void(const string_type&)>;
void render(const basic_data<string_type>& data, const render_handler& handler) {
if (!is_valid()) {
return;
}
context<string_type> ctx{&data};
context_internal<string_type> context{ctx};
render(handler, context);
}
private:
using string_size_type = typename string_type::size_type;
basic_mustache()
: escape_(html_escape<string_type>)
{
}
basic_mustache(const string_type& input, context_internal<string_type>& ctx)
: basic_mustache() {
parser<string_type> parser{input, ctx, root_component_, error_message_};
}
string_type render(context_internal<string_type>& ctx) {
std::basic_ostringstream<typename string_type::value_type> ss;
render([&ss](const string_type& str) {
ss << str;
}, ctx);
return ss.str();
}
void render(const render_handler& handler, context_internal<string_type>& ctx, bool root_renderer = true) {
root_component_.walk_children([&handler, &ctx, this](component<string_type>& comp) -> typename component<string_type>::walk_control {
return render_component(handler, ctx, comp);
});
// process the last line, but only for the top-level renderer
if (root_renderer) {
render_current_line(handler, ctx, nullptr);
}
}
void render_current_line(const render_handler& handler, context_internal<string_type>& ctx, const component<string_type>* comp) const {
// We're at the end of a line, so check the line buffer state to see
// if the line had tags in it, and also if the line is now empty or
// contains whitespace only. if this situation is true, skip the line.
bool output = true;
if (ctx.line_buffer.contained_section_tag && ctx.line_buffer.is_empty_or_contains_only_whitespace()) {
output = false;
}
if (output) {
handler(ctx.line_buffer.data);
if (comp) {
handler(comp->text);
}
}
ctx.line_buffer.clear();
}
void render_result(context_internal<string_type>& ctx, const string_type& text) const {
ctx.line_buffer.data.append(text);
}
typename component<string_type>::walk_control render_component(const render_handler& handler, context_internal<string_type>& ctx, component<string_type>& comp) {
if (comp.is_text()) {
if (comp.is_newline()) {
render_current_line(handler, ctx, &comp);
} else {
render_result(ctx, comp.text);
}
return component<string_type>::walk_control::walk;
}
const mstch_tag<string_type>& tag{comp.tag};
const basic_data<string_type>* var = nullptr;
switch (tag.type) {
case tag_type::variable:
case tag_type::unescaped_variable:
if ((var = ctx.ctx.get(tag.name)) != nullptr) {
if (!render_variable(handler, var, ctx, tag.type == tag_type::variable)) {
return component<string_type>::walk_control::stop;
}
}
break;
case tag_type::section_begin:
if ((var = ctx.ctx.get(tag.name)) != nullptr) {
if (var->is_lambda() || var->is_lambda2()) {
if (!render_lambda(handler, var, ctx, render_lambda_escape::optional, *comp.tag.section_text, true)) {
return component<string_type>::walk_control::stop;
}
} else if (!var->is_false() && !var->is_empty_list()) {
render_section(handler, ctx, comp, var);
}
}
return component<string_type>::walk_control::skip;
case tag_type::section_begin_inverted:
if ((var = ctx.ctx.get(tag.name)) == nullptr || var->is_false() || var->is_empty_list()) {
render_section(handler, ctx, comp, var);
}
return component<string_type>::walk_control::skip;
case tag_type::partial:
if ((var = ctx.ctx.get_partial(tag.name)) != nullptr && (var->is_partial() || var->is_string())) {
const auto& partial_result = var->is_partial() ? var->partial_value()() : var->string_value();
basic_mustache tmpl{partial_result};
tmpl.set_custom_escape(escape_);
if (!tmpl.is_valid()) {
error_message_ = tmpl.error_message();
} else {
tmpl.render(handler, ctx, false);
if (!tmpl.is_valid()) {
error_message_ = tmpl.error_message();
}
}
if (!tmpl.is_valid()) {
return component<string_type>::walk_control::stop;
}
}
break;
case tag_type::set_delimiter:
ctx.delim_set = *comp.tag.delim_set;
break;
default:
break;
}
return component<string_type>::walk_control::walk;
}
enum class render_lambda_escape {
escape,
unescape,
optional,
};
bool render_lambda(const render_handler& handler, const basic_data<string_type>* var, context_internal<string_type>& ctx, render_lambda_escape escape, const string_type& text, bool parse_with_same_context) {
const typename basic_renderer<string_type>::type2 render2 = [this, &ctx, parse_with_same_context, escape](const string_type& text, bool escaped) {
const auto process_template = [this, &ctx, escape, escaped](basic_mustache& tmpl) -> string_type {
if (!tmpl.is_valid()) {
error_message_ = tmpl.error_message();
return {};
}
context_internal<string_type> render_ctx{ctx.ctx}; // start a new line_buffer
const auto str = tmpl.render(render_ctx);
if (!tmpl.is_valid()) {
error_message_ = tmpl.error_message();
return {};
}
bool do_escape = false;
switch (escape) {
case render_lambda_escape::escape:
do_escape = true;
break;
case render_lambda_escape::unescape:
do_escape = false;
break;
case render_lambda_escape::optional:
do_escape = escaped;
break;
}
return do_escape ? escape_(str) : str;
};
if (parse_with_same_context) {
basic_mustache tmpl{text, ctx};
tmpl.set_custom_escape(escape_);
return process_template(tmpl);
}
basic_mustache tmpl{text};
tmpl.set_custom_escape(escape_);
return process_template(tmpl);
};
const typename basic_renderer<string_type>::type1 render = [&render2](const string_type& text) {
return render2(text, false);
};
if (var->is_lambda2()) {
const basic_renderer<string_type> renderer{render, render2};
render_result(ctx, var->lambda2_value()(text, renderer));
} else {
render_current_line(handler, ctx, nullptr);
render_result(ctx, render(var->lambda_value()(text)));
}
return error_message_.empty();
}
bool render_variable(const render_handler& handler, const basic_data<string_type>* var, context_internal<string_type>& ctx, bool escaped) {
if (var->is_string()) {
const auto& varstr = var->string_value();
render_result(ctx, escaped ? escape_(varstr) : varstr);
} else if (var->is_lambda()) {
const render_lambda_escape escape_opt = escaped ? render_lambda_escape::escape : render_lambda_escape::unescape;
return render_lambda(handler, var, ctx, escape_opt, {}, false);
} else if (var->is_lambda2()) {
using streamstring = std::basic_ostringstream<typename string_type::value_type>;
streamstring ss;
ss << "Lambda with render argument is not allowed for regular variables";
error_message_ = ss.str();
return false;
}
return true;
}
void render_section(const render_handler& handler, context_internal<string_type>& ctx, component<string_type>& incomp, const basic_data<string_type>* var) {
const auto callback = [&handler, &ctx, this](component<string_type>& comp) -> typename component<string_type>::walk_control {
return render_component(handler, ctx, comp);
};
if (var && var->is_non_empty_list()) {
for (const auto& item : var->list_value()) {
// account for the section begin tag
ctx.line_buffer.contained_section_tag = true;
const context_pusher<string_type> ctxpusher{ctx, &item};
incomp.walk_children(callback);
// ctx may have been cleared. account for the section end tag
ctx.line_buffer.contained_section_tag = true;
}
} else if (var) {
// account for the section begin tag
ctx.line_buffer.contained_section_tag = true;
const context_pusher<string_type> ctxpusher{ctx, var};
incomp.walk_children(callback);
// ctx may have been cleared. account for the section end tag
ctx.line_buffer.contained_section_tag = true;
} else {
// account for the section begin tag
ctx.line_buffer.contained_section_tag = true;
incomp.walk_children(callback);
// ctx may have been cleared. account for the section end tag
ctx.line_buffer.contained_section_tag = true;
}
}
private:
string_type error_message_;
component<string_type> root_component_;
escape_handler escape_;
};
using mustache = basic_mustache<std::string>;
using data = basic_data<mustache::string_type>;
using object = basic_object<mustache::string_type>;
using list = basic_list<mustache::string_type>;
using partial = basic_partial<mustache::string_type>;
using renderer = basic_renderer<mustache::string_type>;
using lambda = basic_lambda<mustache::string_type>;
using lambda2 = basic_lambda2<mustache::string_type>;
using lambda_t = basic_lambda_t<mustache::string_type>;
using mustachew = basic_mustache<std::wstring>;
using dataw = basic_data<mustachew::string_type>;
} // namespace mustache
} // namespace kainjow
#endif // KAINJOW_MUSTACHE_HPP
