path: root/src/text_asset.cc

/*
    Copyright (C) 2012-2021 Carl Hetherington <cth@carlh.net>

    This file is part of libdcp.

    libdcp is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    libdcp is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with libdcp.  If not, see <http://www.gnu.org/licenses/>.

    In addition, as a special exception, the copyright holders give
    permission to link the code of portions of this program with the
    OpenSSL library under certain conditions as described in each
    individual source file, and distribute linked combinations
    including the two.

    You must obey the GNU General Public License in all respects
    for all of the code used other than OpenSSL.  If you modify
    file(s) with this exception, you may extend this exception to your
    version of the file(s), but you are not obligated to do so.  If you
    do not wish to do so, delete this exception statement from your
    version.  If you delete this exception statement from all source
    files in the program, then also delete it here.
*/


/** @file  src/text_asset.cc
 *  @brief TextAsset class
 */


#include "compose.hpp"
#include "dcp_assert.h"
#include "load_font_node.h"
#include "raw_convert.h"
#include "reel_asset.h"
#include "text_image.h"
#include "text_string.h"
#include "text_asset.h"
#include "text_asset_internal.h"
#include "util.h"
#include "xml.h"
#include <asdcp/AS_DCP.h>
#include <asdcp/KM_util.h>
#include <libxml++/nodes/element.h>
#include <boost/algorithm/string.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/shared_array.hpp>
#include <algorithm>


using std::cerr;
using std::cout;
using std::dynamic_pointer_cast;
using std::make_shared;
using std::map;
using std::pair;
using std::shared_ptr;
using std::string;
using std::vector;
using boost::lexical_cast;
using boost::optional;
using namespace dcp;


TextAsset::TextAsset()
{

}


TextAsset::TextAsset(boost::filesystem::path file)
	: Asset (file)
{

}


string
string_attribute (xmlpp::Element const * node, string name)
{
	auto a = node->get_attribute (name);
	if (!a) {
		throw XMLError (String::compose ("missing attribute %1", name));
	}
	return string (a->get_value ());
}


optional<string>
optional_string_attribute (xmlpp::Element const * node, string name)
{
	auto a = node->get_attribute (name);
	if (!a) {
		return {};
	}
	return string (a->get_value ());
}


optional<bool>
optional_bool_attribute (xmlpp::Element const * node, string name)
{
	auto s = optional_string_attribute (node, name);
	if (!s) {
		return {};
	}

	return (s.get() == "1" || s.get() == "yes");
}


template <class T>
optional<T>
optional_number_attribute (xmlpp::Element const * node, string name)
{
	auto s = optional_string_attribute (node, name);
	if (!s) {
		return boost::optional<T> ();
	}

	std::string t = s.get ();
	boost::erase_all (t, " ");
	return raw_convert<T> (t);
}


TextAsset::ParseState
TextAsset::font_node_state(xmlpp::Element const * node, Standard standard) const
{
	ParseState ps;

	if (standard == Standard::INTEROP) {
		ps.font_id = optional_string_attribute (node, "Id");
	} else {
		ps.font_id = optional_string_attribute (node, "ID");
	}
	ps.size = optional_number_attribute<int64_t> (node, "Size");
	ps.aspect_adjust = optional_number_attribute<float> (node, "AspectAdjust");
	ps.italic = optional_bool_attribute (node, "Italic");
	ps.bold = optional_string_attribute(node, "Weight").get_value_or("normal") == "bold";
	if (standard == Standard::INTEROP) {
		ps.underline = optional_bool_attribute (node, "Underlined");
	} else {
		ps.underline = optional_bool_attribute (node, "Underline");
	}
	auto c = optional_string_attribute (node, "Color");
	if (c) {
		ps.colour = Colour (c.get ());
	}
	auto const e = optional_string_attribute (node, "Effect");
	if (e) {
		ps.effect = string_to_effect (e.get ());
	}
	c = optional_string_attribute (node, "EffectColor");
	if (c) {
		ps.effect_colour = Colour (c.get ());
	}

	return ps;
}

void
TextAsset::position_align(TextAsset::ParseState& ps, xmlpp::Element const * node) const
{
	auto hp = optional_number_attribute<float> (node, "HPosition");
	if (!hp) {
		hp = optional_number_attribute<float> (node, "Hposition");
	}
	if (hp) {
		ps.h_position = hp.get () / 100;
	}

	auto ha = optional_string_attribute (node, "HAlign");
	if (!ha) {
		ha = optional_string_attribute (node, "Halign");
	}
	if (ha) {
		ps.h_align = string_to_halign (ha.get ());
	}

	auto vp = optional_number_attribute<float> (node, "VPosition");
	if (!vp) {
		vp = optional_number_attribute<float> (node, "Vposition");
	}
	if (vp) {
		ps.v_position = vp.get () / 100;
	}

	auto va = optional_string_attribute (node, "VAlign");
	if (!va) {
		va = optional_string_attribute (node, "Valign");
	}
	if (va) {
		ps.v_align = string_to_valign (va.get ());
	}

	if (auto zp = optional_number_attribute<float>(node, "Zposition")) {
		ps.z_position = zp.get() / 100;
	}

	if (auto variable_z = optional_string_attribute(node, "VariableZ")) {
		ps.variable_z = *variable_z;
	}
}


TextAsset::ParseState
TextAsset::text_node_state(xmlpp::Element const * node) const
{
	ParseState ps;

	position_align (ps, node);

	auto d = optional_string_attribute (node, "Direction");
	if (d) {
		ps.direction = string_to_direction (d.get ());
	}

	ps.type = ParseState::Type::TEXT;

	return ps;
}


TextAsset::ParseState
TextAsset::image_node_state(xmlpp::Element const * node) const
{
	ParseState ps;

	position_align (ps, node);

	ps.type = ParseState::Type::IMAGE;

	return ps;
}


TextAsset::ParseState
TextAsset::subtitle_node_state(xmlpp::Element const * node, optional<int> tcr) const
{
	ParseState ps;
	ps.in = Time (string_attribute(node, "TimeIn"), tcr);
	ps.out = Time (string_attribute(node, "TimeOut"), tcr);
	ps.fade_up_time = fade_time (node, "FadeUpTime", tcr);
	ps.fade_down_time = fade_time (node, "FadeDownTime", tcr);

	for (auto child: node->get_children()) {
		auto element = dynamic_cast<xmlpp::Element const*>(child);
		if (element && element->get_name() == "LoadVariableZ") {
			ps.load_variable_z.push_back(LoadVariableZ(element));
		}
	}

	return ps;
}


Time
TextAsset::fade_time(xmlpp::Element const * node, string name, optional<int> tcr) const
{
	auto const u = optional_string_attribute(node, name).get_value_or ("");
	Time t;

	if (u.empty ()) {
		t = Time (0, 0, 0, 20, 250);
	} else if (u.find (":") != string::npos) {
		t = Time (u, tcr);
	} else {
		t = Time (0, 0, 0, lexical_cast<int> (u), tcr.get_value_or(250));
	}

	if (t > Time (0, 0, 8, 0, 250)) {
		t = Time (0, 0, 8, 0, 250);
	}

	return t;
}


void
TextAsset::parse_texts(xmlpp::Element const * node, vector<ParseState>& state, optional<int> tcr, Standard standard)
{
	if (node->get_name() == "Font") {
		state.push_back (font_node_state (node, standard));
	} else if (node->get_name() == "Subtitle") {
		state.push_back (subtitle_node_state (node, tcr));
	} else if (node->get_name() == "Text") {
		state.push_back (text_node_state (node));
	} else if (node->get_name() == "SubtitleList") {
		state.push_back (ParseState ());
	} else if (node->get_name() == "Image") {
		state.push_back (image_node_state (node));
	} else if (node->get_name() == "LoadVariableZ") {
		return;
	} else {
		throw XMLError ("unexpected node " + node->get_name());
	}

	float space_before = 0;

	auto get_text_content = [](xmlpp::Element const* element) {
		string all_content;
		for (auto child: element->get_children()) {
			auto content = dynamic_cast<xmlpp::ContentNode const*>(child);
			if (content) {
				all_content += content->get_content();
			}
		}
		return all_content;
	};

	for (auto i: node->get_children()) {

		if (auto const v = dynamic_cast<xmlpp::ContentNode const *>(i)) {
			maybe_add_text(string{v->get_content()}, state, space_before, standard);
			space_before = 0;
		}

		if (auto const e = dynamic_cast<xmlpp::Element const *>(i)) {
			if (e->get_name() == "Space") {
				if (node->get_name() != "Text") {
					throw XMLError ("Space node found outside Text");
				}
				auto size = optional_string_attribute(e, "Size").get_value_or("0.5");
				if (standard == dcp::Standard::INTEROP) {
					boost::replace_all(size, "em", "");
				}
				space_before += raw_convert<float>(size);
			} else if (e->get_name() == "Ruby") {
				optional<string> base;
				optional<string> annotation;
				optional<float> size;
				optional<RubyPosition> position;
				optional<float> offset;
				optional<float> spacing;
				optional<float> aspect_adjust;
				for (auto ruby_child: e->get_children()) {
					if (auto ruby_element = dynamic_cast<xmlpp::Element const*>(ruby_child)) {
						if (ruby_element->get_name() == "Rb") {
							base = get_text_content(ruby_element);
						} else if (ruby_element->get_name() == "Rt") {
							annotation = get_text_content(ruby_element);
							size = optional_number_attribute<float>(ruby_element, "Size");
							if (auto position_string = optional_string_attribute(ruby_element, "Position")) {
								if (*position_string == "before") {
									position = RubyPosition::BEFORE;
								} else if (*position_string == "after") {
									position = RubyPosition::AFTER;
								} else {
									DCP_ASSERT(false);
								}
							}
							offset = optional_number_attribute<float>(ruby_element, "Offset");
							spacing = optional_number_attribute<float>(ruby_element, "Spacing");
							aspect_adjust = optional_number_attribute<float>(ruby_element, "AspectAdjust");
						}
					}
				}
				DCP_ASSERT(base);
				DCP_ASSERT(annotation);
				auto ruby = Ruby{*base, *annotation};
				if (size) {
					ruby.size = *size;
				}
				if (position) {
					ruby.position = *position;
				}
				if (offset) {
					ruby.offset = *offset;
				}
				if (spacing) {
					ruby.spacing = *spacing;
				}
				if (aspect_adjust) {
					ruby.aspect_adjust = *aspect_adjust;
				}
				maybe_add_text(ruby, state, space_before, standard);
			} else {
				parse_texts(e, state, tcr, standard);
			}
		}
	}

	DCP_ASSERT(!state.empty());
	state.pop_back ();
}


void
TextAsset::maybe_add_text(
	boost::variant<string, Ruby> text,
	vector<ParseState> const & parse_state,
	float space_before,
	Standard standard
	)
{
	auto wanted = [](ParseState const& ps) {
		return ps.type && (ps.type.get() == ParseState::Type::TEXT || ps.type.get() == ParseState::Type::IMAGE);
	};

	if (find_if(parse_state.begin(), parse_state.end(), wanted) == parse_state.end()) {
		return;
	}

	ParseState ps;
	for (auto const& i: parse_state) {
		if (i.font_id) {
			ps.font_id = i.font_id.get();
		}
		if (i.size) {
			ps.size = i.size.get();
		}
		if (i.aspect_adjust) {
			ps.aspect_adjust = i.aspect_adjust.get();
		}
		if (i.italic) {
			ps.italic = i.italic.get();
		}
		if (i.bold) {
			ps.bold = i.bold.get();
		}
		if (i.underline) {
			ps.underline = i.underline.get();
		}
		if (i.colour) {
			ps.colour = i.colour.get();
		}
		if (i.effect) {
			ps.effect = i.effect.get();
		}
		if (i.effect_colour) {
			ps.effect_colour = i.effect_colour.get();
		}
		if (i.h_position) {
			ps.h_position = i.h_position.get();
		}
		if (i.h_align) {
			ps.h_align = i.h_align.get();
		}
		if (i.v_position) {
			ps.v_position = i.v_position.get();
		}
		if (i.v_align) {
			ps.v_align = i.v_align.get();
		}
		if (i.z_position) {
			ps.z_position = i.z_position.get();
		}
		if (i.variable_z) {
			ps.variable_z = i.variable_z.get();
		}
		if (i.direction) {
			ps.direction = i.direction.get();
		}
		if (i.in) {
			ps.in = i.in.get();
		}
		if (i.out) {
			ps.out = i.out.get();
		}
		if (i.fade_up_time) {
			ps.fade_up_time = i.fade_up_time.get();
		}
		if (i.fade_down_time) {
			ps.fade_down_time = i.fade_down_time.get();
		}
		if (i.type) {
			ps.type = i.type.get();
		}
		for (auto j: i.load_variable_z) {
			/* j is a LoadVariableZ from this "sub" ParseState. See if we should add it to the end result */
			auto const k = std::find_if(ps.load_variable_z.begin(), ps.load_variable_z.end(), [j](LoadVariableZ const& z) { return j.id() == z.id(); });
			if (k == ps.load_variable_z.end()) {
				ps.load_variable_z.push_back(j);
			}
		}
	}

	if (!ps.in || !ps.out) {
		/* We're not in a <Subtitle> node; just ignore this content */
		return;
	}

	DCP_ASSERT (ps.type);

	switch (ps.type.get()) {
	case ParseState::Type::TEXT:
	{
		vector<Text::VariableZPosition> variable_z;
		auto iter = std::find_if(ps.load_variable_z.begin(), ps.load_variable_z.end(), [&ps](LoadVariableZ const& z) { return z.id() == ps.variable_z; });
		if (iter != ps.load_variable_z.end()) {
			variable_z = iter->positions();
		}
		_texts.push_back (
			make_shared<TextString>(
				ps.font_id,
				ps.italic.get_value_or (false),
				ps.bold.get_value_or (false),
				ps.underline.get_value_or (false),
				ps.colour.get_value_or (dcp::Colour (255, 255, 255)),
				ps.size.get_value_or (42),
				ps.aspect_adjust.get_value_or (1.0),
				ps.in.get(),
				ps.out.get(),
				ps.h_position.get_value_or(0),
				ps.h_align.get_value_or(HAlign::CENTER),
				ps.v_position.get_value_or(0),
				ps.v_align.get_value_or(VAlign::CENTER),
				ps.z_position.get_value_or(0),
				variable_z,
				ps.direction.get_value_or (Direction::LTR),
				text,
				ps.effect.get_value_or (Effect::NONE),
				ps.effect_colour.get_value_or (dcp::Colour (0, 0, 0)),
				ps.fade_up_time.get_value_or(Time()),
				ps.fade_down_time.get_value_or(Time()),
				space_before
				)
			);
		break;
	}
	case ParseState::Type::IMAGE:
	{
		DCP_ASSERT(text.which() == 0);
		auto text_string = boost::get<string>(text);
		switch (standard) {
		case Standard::INTEROP:
			if (text_string.size() >= 4) {
				/* Remove file extension */
				text_string = text_string.substr(0, text_string.size() - 4);
			}
			break;
		case Standard::SMPTE:
			/* It looks like this urn:uuid: is required, but DoM wasn't expecting it (and not writing it)
			 * until around 2.15.140 so I guess either:
			 *   a) it is not (always) used in the field, or
			 *   b) nobody noticed / complained.
			 */
			if (text_string.substr(0, 9) == "urn:uuid:") {
				text_string = text_string.substr(9);
			}
			break;
		}

		vector<Text::VariableZPosition> variable_z;
		auto iter = std::find_if(ps.load_variable_z.begin(), ps.load_variable_z.end(), [&ps](LoadVariableZ const& z) { return ps.variable_z && z.id() == *ps.variable_z; });
		if (iter != ps.load_variable_z.end()) {
			variable_z = iter->positions();
		}

		/* Add a text with no image data and we'll fill that in later */
		_texts.push_back(
			make_shared<TextImage>(
				ArrayData(),
				text_string,
				ps.in.get(),
				ps.out.get(),
				ps.h_position.get_value_or(0),
				ps.h_align.get_value_or(HAlign::CENTER),
				ps.v_position.get_value_or(0),
				ps.v_align.get_value_or(VAlign::CENTER),
				ps.z_position.get_value_or(0),
				variable_z,
				ps.fade_up_time.get_value_or(Time()),
				ps.fade_down_time.get_value_or(Time())
				)
			);
		break;
	}
	}
}


vector<shared_ptr<const Text>>
TextAsset::texts() const
{
	vector<shared_ptr<const Text>> s;
	for (auto i: _texts) {
		s.push_back (i);
	}
	return s;
}


vector<shared_ptr<const Text>>
TextAsset::texts_during(Time from, Time to, bool starting) const
{
	vector<shared_ptr<const Text>> s;
	for (auto i: _texts) {
		if ((starting && from <= i->in() && i->in() < to) || (!starting && i->out() >= from && i->in() <= to)) {
			s.push_back (i);
		}
	}

	return s;
}


void
TextAsset::add(shared_ptr<Text> s)
{
	_texts.push_back(s);
}


Time
TextAsset::latest_text_out() const
{
	Time t;
	for (auto i: _texts) {
		if (i->out() > t) {
			t = i->out ();
		}
	}

	return t;
}


bool
TextAsset::equals(shared_ptr<const Asset> other_asset, EqualityOptions const& options, NoteHandler note) const
{
	if (!Asset::equals (other_asset, options, note)) {
		return false;
	}

	auto other = dynamic_pointer_cast<const TextAsset> (other_asset);
	if (!other) {
		return false;
	}

	if (_texts.size() != other->_texts.size()) {
		note (NoteType::ERROR, String::compose("different number of texts: %1 vs %2", _texts.size(), other->_texts.size()));
		return false;
	}

	auto i = _texts.begin();
	auto j = other->_texts.begin();

	while (i != _texts.end()) {
		auto string_i = dynamic_pointer_cast<TextString>(*i);
		auto string_j = dynamic_pointer_cast<TextString>(*j);
		auto image_i = dynamic_pointer_cast<TextImage>(*i);
		auto image_j = dynamic_pointer_cast<TextImage>(*j);

		if ((string_i && !string_j) || (image_i && !image_j)) {
			note (NoteType::ERROR, "texts differ: string vs. image");
			return false;
		}

		if (string_i && !string_i->equals(string_j, options, note)) {
			return false;
		}

		if (image_i && !image_i->equals(image_j, options, note)) {
			return false;
		}

		++i;
		++j;
	}

	return true;
}


struct TextSorter
{
	bool operator()(shared_ptr<Text> a, shared_ptr<Text> b) {
		if (a->in() != b->in()) {
			return a->in() < b->in();
		}
		if (a->v_align() == VAlign::BOTTOM) {
			return a->v_position() > b->v_position();
		}
		return a->v_position() < b->v_position();
	}
};


void
TextAsset::pull_fonts(shared_ptr<order::Part> part)
{
	if (part->children.empty ()) {
		return;
	}

	/* Pull up from children */
	for (auto i: part->children) {
		pull_fonts (i);
	}

	if (part->parent) {
		/* Establish the common font features that each of part's children have;
		   these features go into part's font.
		*/
		part->font = part->children.front()->font;
		for (auto i: part->children) {
			part->font.take_intersection (i->font);
		}

		/* Remove common values from part's children's fonts */
		for (auto i: part->children) {
			i->font.take_difference (part->font);
		}
	}

	/* Merge adjacent children with the same font */
	auto i = part->children.begin();
	vector<shared_ptr<order::Part>> merged;

	while (i != part->children.end()) {

		if ((*i)->font.empty ()) {
			merged.push_back (*i);
			++i;
		} else {
			auto j = i;
			++j;
			while (j != part->children.end() && (*i)->font == (*j)->font) {
				++j;
			}
			if (std::distance (i, j) == 1) {
				merged.push_back (*i);
				++i;
			} else {
				shared_ptr<order::Part> group (new order::Part (part, (*i)->font));
				for (auto k = i; k != j; ++k) {
					(*k)->font.clear ();
					group->children.push_back (*k);
				}
				merged.push_back (group);
				i = j;
			}
		}
	}

	part->children = merged;
}


/** @param standard Standard (INTEROP or SMPTE); this is used rather than putting things in the child
 *  class because the differences between the two are fairly subtle.
 */
void
TextAsset::texts_as_xml(xmlpp::Element* xml_root, int time_code_rate, Standard standard) const
{
	auto sorted = _texts;
	std::stable_sort(sorted.begin(), sorted.end(), TextSorter());

	/* Gather our texts into a hierarchy of Subtitle/Text/String objects, writing
	   font information into the bottom level (String) objects.
	*/

	auto root = make_shared<order::Part>(shared_ptr<order::Part>());
	shared_ptr<order::Subtitle> subtitle;
	shared_ptr<order::Text> text;

	Time last_in;
	Time last_out;
	Time last_fade_up_time;
	Time last_fade_down_time;
	HAlign last_h_align;
	float last_h_position;
	VAlign last_v_align;
	float last_v_position;
	float last_z_position;
	Direction last_direction;
	int load_variable_z_index = 1;

	for (auto i: sorted) {
		if (!subtitle ||
		    (last_in != i->in() ||
		     last_out != i->out() ||
		     last_fade_up_time != i->fade_up_time() ||
		     last_fade_down_time != i->fade_down_time())
			) {

			subtitle = make_shared<order::Subtitle>(root, i->in(), i->out(), i->fade_up_time(), i->fade_down_time());
			root->children.push_back (subtitle);

			last_in = i->in ();
			last_out = i->out ();
			last_fade_up_time = i->fade_up_time ();
			last_fade_down_time = i->fade_down_time ();
			text.reset ();
		}

		auto is = dynamic_pointer_cast<TextString>(i);
		if (is) {
			if (!text ||
			    last_h_align != is->h_align() ||
			    fabs(last_h_position - is->h_position()) > ALIGN_EPSILON ||
			    last_v_align != is->v_align() ||
			    fabs(last_v_position - is->v_position()) > ALIGN_EPSILON ||
			    fabs(last_z_position - is->z_position()) > ALIGN_EPSILON ||
			    last_direction != is->direction()
				) {
				text = make_shared<order::Text>(
					subtitle,
					is->h_align(),
					is->h_position(),
					is->v_align(),
					is->v_position(),
					is->z_position(),
					subtitle->find_or_add_variable_z_positions(is->variable_z_positions(), load_variable_z_index),
					is->direction()
					);
				subtitle->children.push_back (text);

				last_h_align = is->h_align ();
				last_h_position = is->h_position ();
				last_v_align = is->v_align ();
				last_v_position = is->v_position ();
				last_z_position = is->z_position();
				last_direction = is->direction ();
			}

			if (is->string_text()) {
				text->children.push_back(make_shared<order::String>(text, order::Font (is, standard), *is->string_text(), is->space_before()));
			} else if (is->ruby_text()) {
				text->children.push_back(make_shared<order::Ruby>(text, order::Font(is, standard), *is->ruby_text()));
			}
		}

		if (auto ii = dynamic_pointer_cast<TextImage>(i)) {
			text.reset ();
			subtitle->children.push_back (
				make_shared<order::Image>(
					subtitle, ii->id(),
					ii->png_image(),
					ii->h_align(),
					ii->h_position(),
					ii->v_align(),
					ii->v_position(),
					ii->z_position(),
					subtitle->find_or_add_variable_z_positions(ii->variable_z_positions(), load_variable_z_index)
					)
				);
		}
	}

	/* Pull font changes as high up the hierarchy as we can */

	pull_fonts (root);

	/* Write XML */

	order::Context context;
	context.time_code_rate = time_code_rate;
	context.standard = standard;
	context.spot_number = 1;

	root->write_xml (xml_root, context);
}


map<string, ArrayData>
TextAsset::font_data() const
{
	map<string, ArrayData> out;
	for (auto const& i: _fonts) {
		out[i.load_id] = i.data;
	}
	return out;
}


map<string, boost::filesystem::path>
TextAsset::font_filenames() const
{
	map<string, boost::filesystem::path> out;
	for (auto const& i: _fonts) {
		if (i.file) {
			out[i.load_id] = *i.file;
		}
	}
	return out;
}


/** Replace empty IDs in any <LoadFontId> and <Font> tags with
 *  a dummy string.  Some systems give errors with empty font IDs
 *  (see DCP-o-matic bug #1689).
 */
void
TextAsset::fix_empty_font_ids()
{
	bool have_empty = false;
	vector<string> ids;
	for (auto i: load_font_nodes()) {
		if (i->id == "") {
			have_empty = true;
		} else {
			ids.push_back (i->id);
		}
	}

	if (!have_empty) {
		return;
	}

	string const empty_id = unique_string (ids, "font");

	for (auto i: load_font_nodes()) {
		if (i->id == "") {
			i->id = empty_id;
		}
	}

	for (auto i: _texts) {
		auto j = dynamic_pointer_cast<TextString>(i);
		if (j && j->font() && j->font().get() == "") {
			j->set_font (empty_id);
		}
	}
}


namespace {

struct State
{
	int indent;
	string xml;
	int disable_formatting;
};

}


static
void
format_xml_node (xmlpp::Node const* node, State& state)
{
	if (auto text_node = dynamic_cast<const xmlpp::TextNode*>(node)) {
		string content = text_node->get_content();
		boost::replace_all(content, "&", "&amp;");
		boost::replace_all(content, "<", "&lt;");
		boost::replace_all(content, ">", "&gt;");
		state.xml += content;
	} else if (auto element = dynamic_cast<const xmlpp::Element*>(node)) {
		++state.indent;

		auto children = element->get_children();
		auto const should_disable_formatting =
			std::any_of(
				children.begin(), children.end(),
				[](xmlpp::Node const* node) { return static_cast<bool>(dynamic_cast<const xmlpp::ContentNode*>(node)); }
				) || element->get_name() == "Text";

		if (!state.disable_formatting) {
			state.xml += "\n" + string(state.indent * 2, ' ');
		}

		state.xml += "<" + element->get_name();

		for (auto attribute: element->get_attributes()) {
			state.xml += String::compose(" %1=\"%2\"", attribute->get_name().raw(), attribute->get_value().raw());
		}

		if (children.empty()) {
			state.xml += "/>";
		} else {
			state.xml += ">";

			if (should_disable_formatting) {
				++state.disable_formatting;
			}

			for (auto child: children) {
				format_xml_node(child, state);
			}

			if (!state.disable_formatting) {
				state.xml += "\n" + string(state.indent * 2, ' ');
			}

			state.xml += String::compose("</%1>", element->get_name().raw());

			if (should_disable_formatting) {
				--state.disable_formatting;
			}
		}

		--state.indent;
	}
}


/** Format XML much as write_to_string_formatted() would do, except without adding any white space
 *  to <Text> nodes.  This is an attempt to avoid changing what is actually displayed while also
 *  formatting the XML in such a way as to avoid DoM bug 2205.
 *
 *  xml_namespace is an optional namespace for the root node; it would be nicer to set this up with
 *  set_namespace_declaration in the caller and then to extract it here but I couldn't find a way
 *  to get all namespaces with the libxml++ API.
 */
string
TextAsset::format_xml(xmlpp::Document const& document, optional<pair<string, string>> xml_namespace)
{
	auto root = document.get_root_node();

	State state = {};
	state.xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<" + root->get_name();

	if (xml_namespace) {
		if (xml_namespace->first.empty()) {
			state.xml += String::compose(" xmlns=\"%1\"", xml_namespace->second);
		} else {
			state.xml += String::compose(" xmlns:%1=\"%2\"", xml_namespace->first, xml_namespace->second);
		}
	}

	for (auto attribute: root->get_attributes()) {
		state.xml += String::compose(" %1=\"%2\"", attribute->get_name().raw(), attribute->get_value().raw());
	}

	state.xml += ">";

	for (auto child: document.get_root_node()->get_children()) {
		format_xml_node(child, state);
	}

	state.xml += String::compose("\n</%1>\n", root->get_name().raw());

	return state.xml;
}


void
TextAsset::ensure_font(string load_id, dcp::ArrayData data)
{
	if (std::find_if(_fonts.begin(), _fonts.end(), [load_id](Font const& font) { return font.load_id == load_id; }) == _fonts.end()) {
		add_font(load_id, data);
	}
}