Move AssetMap handling out to a separate class.

9 files changed, 403 insertions, 175 deletions

diff --git a/src/asset.cc b/src/asset.cc
index 6e200b0d..372779b1 100644
--- a/src/asset.cc
+++ b/src/asset.cc
@@ -38,6 +38,7 @@
 
 
 #include "asset.h"
+#include "asset_map.h"
 #include "compose.hpp"
 #include "dcp_assert.h"
 #include "exceptions.h"
@@ -102,15 +103,15 @@ Asset::add_to_pkl (shared_ptr<PKL> pkl, path root) const
 
 
 void
-Asset::write_to_assetmap (xmlpp::Node* node, path root) const
+Asset::add_to_assetmap (AssetMap& asset_map, path root) const
 {
 	DCP_ASSERT (_file);
-	write_file_to_assetmap (node, root, _file.get(), _id);
+	add_file_to_assetmap (asset_map, root, _file.get(), _id);
 }
 
 
 void
-Asset::write_file_to_assetmap (xmlpp::Node* node, path root, path file, string id)
+Asset::add_file_to_assetmap (AssetMap& asset_map, path root, path file, string id)
 {
 	auto path = relative_to_root (
 		canonical(root),
@@ -124,15 +125,7 @@ Asset::write_file_to_assetmap (xmlpp::Node* node, path root, path file, string i
 		return;
 	}
 
-	auto asset = node->add_child ("Asset");
-	asset->add_child("Id")->add_child_text("urn:uuid:" + id);
-	auto chunk_list = asset->add_child ("ChunkList");
-	auto chunk = chunk_list->add_child ("Chunk");
-
-	chunk->add_child("Path")->add_child_text(path.get().generic_string());
-	chunk->add_child("VolumeIndex")->add_child_text("1");
-	chunk->add_child("Offset")->add_child_text("0");
-	chunk->add_child("Length")->add_child_text(raw_convert<string>(file_size(file)));
+	asset_map.add_asset(id, file, false);
 }
 
 
diff --git a/src/asset.h b/src/asset.h
index 88c7d1d1..3af49119 100644
--- a/src/asset.h
+++ b/src/asset.h
@@ -60,6 +60,9 @@ struct asset_test;
 namespace dcp {
 
 
+class AssetMap;
+
+
 /** @class Asset
  *  @brief Parent class for DCP assets, i.e. picture, sound, subtitles, closed captions, CPLs, fonts
  *
@@ -89,7 +92,7 @@ public:
 		NoteHandler note
 		) const;
 
-	virtual void write_to_assetmap (xmlpp::Node* node, boost::filesystem::path root) const;
+	virtual void add_to_assetmap (AssetMap& asset_map, boost::filesystem::path root) const;
 
 	virtual void add_to_pkl (std::shared_ptr<PKL> pkl, boost::filesystem::path root) const;
 
@@ -121,7 +124,7 @@ protected:
 	/** The most recent disk file used to read or write this asset */
 	mutable boost::optional<boost::filesystem::path> _file;
 
-	static void write_file_to_assetmap (xmlpp::Node* node, boost::filesystem::path root, boost::filesystem::path file, std::string id);
+	static void add_file_to_assetmap (AssetMap& asset_map, boost::filesystem::path root, boost::filesystem::path file, std::string id);
 
 private:
 	friend struct ::asset_test;
diff --git a/src/asset_map.cc b/src/asset_map.cc
new file mode 100644
index 00000000..4b6d828c
--- /dev/null
+++ b/src/asset_map.cc
@@ -0,0 +1,218 @@
+/*
+    Copyright (C) 2012-2022 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.
+*/
+
+
+#include "asset_map.h"
+#include "dcp_assert.h"
+#include "exceptions.h"
+#include "raw_convert.h"
+#include "warnings.h"
+LIBDCP_DISABLE_WARNINGS
+#include <libxml++/libxml++.h>
+LIBDCP_ENABLE_WARNINGS
+#include <boost/algorithm/string.hpp>
+
+
+
+using std::map;
+using std::string;
+using std::vector;
+using boost::algorithm::starts_with;
+using namespace dcp;
+
+
+static string const assetmap_interop_ns = "http://www.digicine.com/PROTO-ASDCP-AM-20040311#";
+static string const assetmap_smpte_ns   = "http://www.smpte-ra.org/schemas/429-9/2007/AM";
+
+
+AssetMap::AssetMap(boost::filesystem::path path)
+	: _path(path)
+{
+	cxml::Document doc("AssetMap");
+
+	doc.read_file(path);
+	if (doc.namespace_uri() == assetmap_interop_ns) {
+		_standard = Standard::INTEROP;
+	} else if (doc.namespace_uri() == assetmap_smpte_ns) {
+		_standard = Standard::SMPTE;
+	} else {
+		boost::throw_exception(XMLError("Unrecognised Assetmap namespace " + doc.namespace_uri()));
+	}
+
+	_id = remove_urn_uuid(doc.string_child("Id"));
+	_annotation_text = doc.optional_string_child("AnnotationText");
+        _issue_date = doc.string_child("IssueDate");
+        _issuer = doc.string_child("Issuer");
+        _creator = doc.string_child("Creator");
+
+	for (auto asset: doc.node_child("AssetList")->node_children("Asset")) {
+                _assets.push_back(Asset(asset, _path->parent_path(), _standard));
+        }
+}
+
+
+AssetMap::Asset::Asset(cxml::ConstNodePtr node, boost::filesystem::path root, dcp::Standard standard)
+        : Object(remove_urn_uuid(node->string_child("Id")))
+{
+	if (node->node_child("ChunkList")->node_children("Chunk").size() != 1) {
+		boost::throw_exception (XMLError ("unsupported asset chunk count"));
+	}
+
+	auto path_from_xml = node->node_child("ChunkList")->node_child("Chunk")->string_child("Path");
+	if (starts_with(path_from_xml, "file://")) {
+		path_from_xml = path_from_xml.substr(7);
+	}
+
+	_path = root / path_from_xml;
+
+	switch (standard) {
+	case Standard::INTEROP:
+		_pkl = static_cast<bool>(node->optional_node_child("PackingList"));
+		break;
+	case Standard::SMPTE:
+	{
+		auto pkl_bool = node->optional_string_child("PackingList");
+		_pkl = pkl_bool && *pkl_bool == "true";
+		break;
+	}
+	}
+}
+
+
+void
+AssetMap::add_asset(string id, boost::filesystem::path path, bool pkl)
+{
+        _assets.push_back(Asset(id, path, pkl));
+}
+
+
+void
+AssetMap::clear_assets()
+{
+	_assets.clear();
+}
+
+
+map<std::string, boost::filesystem::path>
+AssetMap::asset_ids_and_paths() const
+{
+        auto paths = map<string, boost::filesystem::path>();
+        for (auto asset: _assets) {
+                paths[asset.id()] = asset.path();
+        }
+        return paths;
+}
+
+
+vector<boost::filesystem::path>
+AssetMap::pkl_paths() const
+{
+        auto paths = std::vector<boost::filesystem::path>();
+        for (auto asset: _assets) {
+                if (asset.pkl()) {
+                        paths.push_back(asset.path());
+                }
+        }
+        return paths;
+}
+
+
+void
+AssetMap::write_xml(boost::filesystem::path path) const
+{
+	xmlpp::Document doc;
+	xmlpp::Element* root;
+
+	switch (_standard) {
+	case Standard::INTEROP:
+		root = doc.create_root_node("AssetMap", assetmap_interop_ns);
+		break;
+	case Standard::SMPTE:
+		root = doc.create_root_node("AssetMap", assetmap_smpte_ns);
+		break;
+	default:
+		DCP_ASSERT (false);
+	}
+
+	root->add_child("Id")->add_child_text("urn:uuid:" + _id);
+	if (_annotation_text) {
+		root->add_child("AnnotationText")->add_child_text(*_annotation_text);
+	}
+
+	switch (_standard) {
+	case Standard::INTEROP:
+		root->add_child("VolumeCount")->add_child_text("1");
+		root->add_child("IssueDate")->add_child_text(_issue_date);
+		root->add_child("Issuer")->add_child_text(_issuer);
+		root->add_child("Creator")->add_child_text(_creator);
+		break;
+	case Standard::SMPTE:
+		root->add_child("Creator")->add_child_text(_creator);
+		root->add_child("VolumeCount")->add_child_text("1");
+		root->add_child("IssueDate")->add_child_text(_issue_date);
+		root->add_child("Issuer")->add_child_text(_issuer);
+		break;
+	default:
+		DCP_ASSERT (false);
+	}
+
+	auto asset_list = root->add_child("AssetList");
+	for (auto const& asset: _assets) {
+		asset.write_xml(asset_list, path.parent_path());
+	}
+
+	doc.write_to_file_formatted(path.string(), "UTF-8");
+	_path = path;
+}
+
+
+void
+AssetMap::Asset::write_xml(xmlpp::Element* asset_list, boost::filesystem::path dcp_root_directory) const
+{
+	auto node = asset_list->add_child("Asset");
+	node->add_child("Id")->add_child_text("urn:uuid:" + _id);
+	if (_pkl) {
+		node->add_child("PackingList")->add_child_text("true");
+	}
+	auto chunk_list = node->add_child("ChunkList");
+	auto chunk = chunk_list->add_child("Chunk");
+
+	auto relative_path = relative_to_root(boost::filesystem::canonical(dcp_root_directory), boost::filesystem::canonical(_path));
+	DCP_ASSERT(relative_path);
+
+	chunk->add_child("Path")->add_child_text(relative_path->generic_string());
+	chunk->add_child("VolumeIndex")->add_child_text("1");
+	chunk->add_child("Offset")->add_child_text("0");
+	chunk->add_child("Length")->add_child_text(raw_convert<string>(boost::filesystem::file_size(_path)));
+}
+
diff --git a/src/asset_map.h b/src/asset_map.h
new file mode 100644
index 00000000..d135380f
--- /dev/null
+++ b/src/asset_map.h
@@ -0,0 +1,115 @@
+/*
+    Copyright (C) 2012-2022 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.
+*/
+
+
+#include "object.h"
+#include "types.h"
+#include <libcxml/cxml.h>
+#include <boost/filesystem.hpp>
+#include <boost/optional.hpp>
+#include <string>
+#include <vector>
+
+
+namespace dcp {
+
+
+class AssetMap : public Object
+{
+public:
+	AssetMap(Standard standard, boost::optional<std::string> annotation_text, std::string issue_date, std::string issuer, std::string creator)
+		: _standard(standard)
+		, _annotation_text(annotation_text)
+		, _issue_date(issue_date)
+		, _issuer(issuer)
+		, _creator(creator)
+        {}
+
+	explicit AssetMap(boost::filesystem::path path);
+
+	boost::optional<boost::filesystem::path> path() const {
+		return _path;
+	}
+
+	std::map<std::string, boost::filesystem::path> asset_ids_and_paths() const;
+
+	std::vector<boost::filesystem::path> pkl_paths() const;
+
+	dcp::Standard standard() const {
+		return _standard;
+	}
+
+	void clear_assets();
+	void add_asset(std::string id, boost::filesystem::path path, bool pkl);
+
+	void write_xml(boost::filesystem::path path) const;
+
+	class Asset : public Object
+	{
+	public:
+		Asset(std::string id, boost::filesystem::path path, bool pkl)
+			: Object(id)
+			, _path(path)
+			, _pkl(pkl)
+		{}
+
+		Asset(cxml::ConstNodePtr node, boost::filesystem::path root, dcp::Standard standard);
+
+		boost::filesystem::path path() const {
+			return _path;
+		}
+
+		bool pkl() const {
+			return _pkl;
+		}
+
+		void write_xml(xmlpp::Element* asset_list, boost::filesystem::path dcp_root_directory) const;
+
+	private:
+		boost::filesystem::path _path;
+		bool _pkl = false;
+	};
+
+private:
+	dcp::Standard _standard;
+	boost::optional<std::string> _annotation_text;
+        std::string _issue_date;
+        std::string _issuer;
+        std::string _creator;
+	std::vector<Asset> _assets;
+	mutable boost::optional<boost::filesystem::path> _path;
+};
+
+
+}
+
diff --git a/src/dcp.cc b/src/dcp.cc
index 803701f5..5da4bbd6 100644
--- a/src/dcp.cc
+++ b/src/dcp.cc
@@ -91,8 +91,6 @@ using boost::optional;
 using namespace dcp;
 
 
-static string const assetmap_interop_ns = "http://www.digicine.com/PROTO-ASDCP-AM-20040311#";
-static string const assetmap_smpte_ns   = "http://www.smpte-ra.org/schemas/429-9/2007/AM";
 static string const volindex_interop_ns = "http://www.digicine.com/PROTO-ASDCP-VL-20040311#";
 static string const volindex_smpte_ns   = "http://www.smpte-ra.org/schemas/429-9/2007/AM";
 
@@ -113,63 +111,25 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 {
 	/* Read the ASSETMAP and PKL */
 
-	if (boost::filesystem::exists (_directory / "ASSETMAP")) {
-		_asset_map = _directory / "ASSETMAP";
-	} else if (boost::filesystem::exists (_directory / "ASSETMAP.xml")) {
-		_asset_map = _directory / "ASSETMAP.xml";
+	boost::filesystem::path asset_map_path;
+	if (boost::filesystem::exists(_directory / "ASSETMAP")) {
+		asset_map_path = _directory / "ASSETMAP";
+	} else if (boost::filesystem::exists(_directory / "ASSETMAP.xml")) {
+		asset_map_path = _directory / "ASSETMAP.xml";
 	} else {
-		boost::throw_exception (MissingAssetmapError(_directory));
+		boost::throw_exception(MissingAssetmapError(_directory));
 	}
 
-	cxml::Document asset_map ("AssetMap");
-
-	asset_map.read_file (_asset_map.get());
-	if (asset_map.namespace_uri() == assetmap_interop_ns) {
-		_standard = Standard::INTEROP;
-	} else if (asset_map.namespace_uri() == assetmap_smpte_ns) {
-		_standard = Standard::SMPTE;
-	} else {
-		boost::throw_exception (XMLError ("Unrecognised Assetmap namespace " + asset_map.namespace_uri()));
-	}
-
-	auto asset_nodes = asset_map.node_child("AssetList")->node_children ("Asset");
-	map<string, boost::filesystem::path> paths;
-	vector<boost::filesystem::path> pkl_paths;
-	for (auto i: asset_nodes) {
-		if (i->node_child("ChunkList")->node_children("Chunk").size() != 1) {
-			boost::throw_exception (XMLError ("unsupported asset chunk count"));
-		}
-		auto p = i->node_child("ChunkList")->node_child("Chunk")->string_child ("Path");
-		if (starts_with (p, "file://")) {
-			p = p.substr (7);
-		}
-		switch (*_standard) {
-		case Standard::INTEROP:
-			if (i->optional_node_child("PackingList")) {
-				pkl_paths.push_back (p);
-			} else {
-				paths.insert (make_pair(remove_urn_uuid(i->string_child("Id")), p));
-			}
-			break;
-		case Standard::SMPTE:
-		{
-			auto pkl_bool = i->optional_string_child("PackingList");
-			if (pkl_bool && *pkl_bool == "true") {
-				pkl_paths.push_back (p);
-			} else {
-				paths.insert (make_pair(remove_urn_uuid(i->string_child("Id")), p));
-			}
-			break;
-		}
-		}
-	}
+	_asset_map = AssetMap(asset_map_path);
+	auto const pkl_paths = _asset_map->pkl_paths();
+	auto const standard = _asset_map->standard();
 
 	if (pkl_paths.empty()) {
 		boost::throw_exception (XMLError ("No packing lists found in asset map"));
 	}
 
 	for (auto i: pkl_paths) {
-		_pkls.push_back (make_shared<PKL>(_directory / i));
+		_pkls.push_back(make_shared<PKL>(i));
 	}
 
 	/* Now we have:
@@ -184,10 +144,11 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 	*/
 	vector<shared_ptr<Asset>> other_assets;
 
-	for (auto i: paths) {
-		auto path = _directory / i.second;
+	auto ids_and_paths = _asset_map->asset_ids_and_paths();
+	for (auto i: ids_and_paths) {
+		auto path = i.second;
 
-		if (i.second.empty()) {
+		if (path == _directory) {
 			/* I can't see how this is valid, but it's
 			   been seen in the wild with a DCP that
 			   claims to come from ClipsterDCI 5.10.0.5.
@@ -229,8 +190,8 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 		pkl_type = pkl_type->substr(0, pkl_type->find(";"));
 
 		if (
-			pkl_type == remove_parameters(CPL::static_pkl_type(*_standard)) ||
-			pkl_type == remove_parameters(InteropSubtitleAsset::static_pkl_type(*_standard))) {
+			pkl_type == remove_parameters(CPL::static_pkl_type(standard)) ||
+			pkl_type == remove_parameters(InteropSubtitleAsset::static_pkl_type(standard))) {
 			auto p = new xmlpp::DomParser;
 			try {
 				p->parse_file (path.string());
@@ -244,21 +205,21 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 
 			if (root == "CompositionPlaylist") {
 				auto cpl = make_shared<CPL>(path);
-				if (_standard && cpl->standard() != _standard.get() && notes) {
+				if (cpl->standard() != standard && notes) {
 					notes->push_back ({VerificationNote::Type::ERROR, VerificationNote::Code::MISMATCHED_STANDARD});
 				}
 				_cpls.push_back (cpl);
 			} else if (root == "DCSubtitle") {
-				if (_standard && _standard.get() == Standard::SMPTE && notes) {
+				if (standard == Standard::SMPTE && notes) {
 					notes->push_back (VerificationNote(VerificationNote::Type::ERROR, VerificationNote::Code::MISMATCHED_STANDARD));
 				}
 				other_assets.push_back (make_shared<InteropSubtitleAsset>(path));
 			}
 		} else if (
-			*pkl_type == remove_parameters(PictureAsset::static_pkl_type(*_standard)) ||
-			*pkl_type == remove_parameters(SoundAsset::static_pkl_type(*_standard)) ||
-			*pkl_type == remove_parameters(AtmosAsset::static_pkl_type(*_standard)) ||
-			*pkl_type == remove_parameters(SMPTESubtitleAsset::static_pkl_type(*_standard))
+			*pkl_type == remove_parameters(PictureAsset::static_pkl_type(standard)) ||
+			*pkl_type == remove_parameters(SoundAsset::static_pkl_type(standard)) ||
+			*pkl_type == remove_parameters(AtmosAsset::static_pkl_type(standard)) ||
+			*pkl_type == remove_parameters(SMPTESubtitleAsset::static_pkl_type(standard))
 			) {
 
 			bool found_threed_marked_as_twod = false;
@@ -266,7 +227,7 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 			if (found_threed_marked_as_twod && notes) {
 				notes->push_back ({VerificationNote::Type::WARNING, VerificationNote::Code::THREED_ASSET_MARKED_AS_TWOD, path});
 			}
-		} else if (*pkl_type == remove_parameters(FontAsset::static_pkl_type(*_standard))) {
+		} else if (*pkl_type == remove_parameters(FontAsset::static_pkl_type(standard))) {
 			other_assets.push_back (make_shared<FontAsset>(i.first, path));
 		} else if (*pkl_type == "image/png") {
 			/* It's an Interop PNG subtitle; let it go */
@@ -281,7 +242,7 @@ DCP::read (vector<dcp::VerificationNote>* notes, bool ignore_incorrect_picture_m
 	if (notes) {
 		for (auto i: cpls()) {
 			for (auto j: i->reel_file_assets()) {
-				if (!j->asset_ref().resolved() && paths.find(j->asset_ref().id()) == paths.end()) {
+				if (!j->asset_ref().resolved() && ids_and_paths.find(j->asset_ref().id()) == ids_and_paths.end()) {
 					notes->push_back (VerificationNote(VerificationNote::Type::WARNING, VerificationNote::Code::EXTERNAL_ASSET, j->asset_ref().id()));
 				}
 			}
@@ -410,80 +371,6 @@ DCP::write_volindex (Standard standard) const
 
 
 void
-DCP::write_assetmap (
-	Standard standard, string pkl_uuid, boost::filesystem::path pkl_path,
-	string issuer, string creator, string issue_date, string annotation_text
-	) const
-{
-	auto p = _directory;
-
-	switch (standard) {
-	case Standard::INTEROP:
-		p /= "ASSETMAP";
-		break;
-	case Standard::SMPTE:
-		p /= "ASSETMAP.xml";
-		break;
-	default:
-		DCP_ASSERT (false);
-	}
-
-	xmlpp::Document doc;
-	xmlpp::Element* root;
-
-	switch (standard) {
-	case Standard::INTEROP:
-		root = doc.create_root_node ("AssetMap", assetmap_interop_ns);
-		break;
-	case Standard::SMPTE:
-		root = doc.create_root_node ("AssetMap", assetmap_smpte_ns);
-		break;
-	default:
-		DCP_ASSERT (false);
-	}
-
-	root->add_child("Id")->add_child_text ("urn:uuid:" + make_uuid());
-	root->add_child("AnnotationText")->add_child_text (annotation_text);
-
-	switch (standard) {
-	case Standard::INTEROP:
-		root->add_child("VolumeCount")->add_child_text ("1");
-		root->add_child("IssueDate")->add_child_text (issue_date);
-		root->add_child("Issuer")->add_child_text (issuer);
-		root->add_child("Creator")->add_child_text (creator);
-		break;
-	case Standard::SMPTE:
-		root->add_child("Creator")->add_child_text (creator);
-		root->add_child("VolumeCount")->add_child_text ("1");
-		root->add_child("IssueDate")->add_child_text (issue_date);
-		root->add_child("Issuer")->add_child_text (issuer);
-		break;
-	default:
-		DCP_ASSERT (false);
-	}
-
-	auto asset_list = root->add_child ("AssetList");
-
-	auto asset = asset_list->add_child ("Asset");
-	asset->add_child("Id")->add_child_text ("urn:uuid:" + pkl_uuid);
-	asset->add_child("PackingList")->add_child_text ("true");
-	auto chunk_list = asset->add_child ("ChunkList");
-	auto chunk = chunk_list->add_child ("Chunk");
-	chunk->add_child("Path")->add_child_text (pkl_path.filename().string());
-	chunk->add_child("VolumeIndex")->add_child_text ("1");
-	chunk->add_child("Offset")->add_child_text ("0");
-	chunk->add_child("Length")->add_child_text (raw_convert<string> (boost::filesystem::file_size (pkl_path)));
-
-	for (auto i: assets()) {
-		i->write_to_assetmap (asset_list, _directory);
-	}
-
-	doc.write_to_file_formatted (p.string (), "UTF-8");
-	_asset_map = p;
-}
-
-
-void
 DCP::write_xml (
 	string issuer,
 	string creator,
@@ -530,8 +417,22 @@ DCP::write_xml (
 	auto pkl_path = _directory / name_format.get(values, "_" + pkl->id() + ".xml");
 	pkl->write (pkl_path, signer);
 
+	if (!_asset_map) {
+		_asset_map = AssetMap(standard, annotation_text, issue_date, issuer, creator);
+	}
+
+	/* The assets may have changed since we read the asset map, so re-add them */
+	_asset_map->clear_assets();
+	_asset_map->add_asset(pkl->id(), pkl_path, true);
+	for (auto asset: assets()) {
+		asset->add_to_assetmap(*_asset_map, _directory);
+	}
+
+	_asset_map->write_xml(
+		_directory / (standard == Standard::INTEROP ? "ASSETMAP" : "ASSETMAP.xml")
+		);
+
 	write_volindex (standard);
-	write_assetmap (standard, pkl->id(), pkl_path, issuer, creator, issue_date, annotation_text);
 }
 
 
diff --git a/src/dcp.h b/src/dcp.h
index a70ff8d1..48c36e7a 100644
--- a/src/dcp.h
+++ b/src/dcp.h
@@ -41,6 +41,7 @@
 #define LIBDCP_DCP_H
 
 
+#include "asset_map.h"
 #include "certificate.h"
 #include "compose.hpp"
 #include "metadata.h"
@@ -163,7 +164,11 @@ public:
 
 	/** @return Standard of a DCP that was read in */
 	boost::optional<Standard> standard () const {
-		return _standard;
+		if (!_asset_map) {
+			return {};
+		}
+
+		return _asset_map->standard();
 	}
 
 	boost::filesystem::path directory () const {
@@ -177,8 +182,12 @@ public:
 		return _pkls;
 	}
 
-	boost::optional<boost::filesystem::path> asset_map_path () {
-		return _asset_map;
+	boost::optional<boost::filesystem::path> asset_map_path() {
+		if (!_asset_map) {
+			return {};
+		}
+
+		return _asset_map->path();
 	}
 
 	static std::vector<boost::filesystem::path> directories_from_files (std::vector<boost::filesystem::path> files);
@@ -187,26 +196,13 @@ private:
 
 	void write_volindex (Standard standard) const;
 
-	/** Write the ASSETMAP file.
-	 *  @param pkl_uuid UUID of our PKL.
-	 *  @param pkl_path Pathname of our PKL file.
-	 */
-	void write_assetmap (
-		Standard standard, std::string pkl_uuid, boost::filesystem::path pkl_path,
-		std::string issuer, std::string creator, std::string issue_date, std::string annotation_text
-		) const;
-
 	/** The directory that we are writing to */
 	boost::filesystem::path _directory;
 	/** The CPLs that make up this DCP */
 	std::vector<std::shared_ptr<CPL>> _cpls;
 	/** The PKLs that make up this DCP */
 	std::vector<std::shared_ptr<PKL>> _pkls;
-	/** File that the ASSETMAP was read from or last written to */
-	mutable boost::optional<boost::filesystem::path> _asset_map;
-
-	/** Standard of DCP that was read in */
-	boost::optional<Standard> _standard;
+	boost::optional<AssetMap> _asset_map;
 };
 
 
diff --git a/src/interop_subtitle_asset.cc b/src/interop_subtitle_asset.cc
index 798f1cda..f3552abe 100644
--- a/src/interop_subtitle_asset.cc
+++ b/src/interop_subtitle_asset.cc
@@ -267,15 +267,15 @@ InteropSubtitleAsset::add_font_assets (vector<shared_ptr<Asset>>& assets)
 
 
 void
-InteropSubtitleAsset::write_to_assetmap (xmlpp::Node* node, boost::filesystem::path root) const
+InteropSubtitleAsset::add_to_assetmap (AssetMap& asset_map, boost::filesystem::path root) const
 {
-	Asset::write_to_assetmap (node, root);
+	Asset::add_to_assetmap(asset_map, root);
 
 	for (auto i: _subtitles) {
-		auto im = dynamic_pointer_cast<dcp::SubtitleImage> (i);
+		auto im = dynamic_pointer_cast<dcp::SubtitleImage>(i);
 		if (im) {
-			DCP_ASSERT (im->file());
-			write_file_to_assetmap (node, root, im->file().get(), im->id());
+			DCP_ASSERT(im->file());
+			add_file_to_assetmap(asset_map, root, im->file().get(), im->id());
 		}
 	}
 }
diff --git a/src/interop_subtitle_asset.h b/src/interop_subtitle_asset.h
index b953b303..670dee27 100644
--- a/src/interop_subtitle_asset.h
+++ b/src/interop_subtitle_asset.h
@@ -68,7 +68,7 @@ public:
 		NoteHandler note
 		) const override;
 
-	void write_to_assetmap (xmlpp::Node* node, boost::filesystem::path root) const override;
+	void add_to_assetmap (AssetMap& asset_map, boost::filesystem::path root) const override;
 	void add_to_pkl (std::shared_ptr<PKL> pkl, boost::filesystem::path root) const override;
 
 	std::vector<std::shared_ptr<LoadFontNode>> load_font_nodes () const override;
diff --git a/src/wscript b/src/wscript
index da4d0d1e..2788183b 100644
--- a/src/wscript
+++ b/src/wscript
@@ -36,6 +36,7 @@ def build(bld):
     source = """
              array_data.cc
              asset.cc
+             asset_map.cc
              asset_factory.cc
              asset_writer.cc
              atmos_asset.cc
@@ -123,6 +124,7 @@ def build(bld):
     headers = """
               array_data.h
               asset.h
+              asset_map.h
               asset_reader.h
               asset_writer.h
               atmos_asset.h