shaka-packager/packager/mpd/base/xml/xml_node.h

241 lines
9.2 KiB
C++

// Copyright 2014 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
//
// Classes to wrap XML operations. XmlNode is a generic wrapper class for
// XmlNode in libxml2. There are also MPD XML specific classes as well.
#ifndef MPD_BASE_XML_XML_NODE_H_
#define MPD_BASE_XML_XML_NODE_H_
#include <cstdint>
#include <list>
#include <set>
#include <string>
#include <vector>
#include <packager/macros/classes.h>
#include <packager/mpd/base/content_protection_element.h>
#include <packager/mpd/base/media_info.pb.h>
typedef struct _xmlNode xmlNode;
namespace shaka {
class MpdBuilder;
struct SegmentInfo;
namespace xml {
class XmlNode;
} // namespace xml
// Defined in tests under mpd/test/xml_compare.h
bool XmlEqual(const std::string& xml1, const xml::XmlNode& xml2);
namespace xml {
/// These classes are wrapper classes for XML elements for generating MPD.
/// None of the pointer parameters should be NULL. None of the methods are meant
/// to be overridden.
class XmlNode {
public:
/// Make an XML element.
/// @param name is the name of the element, which should not be NULL.
explicit XmlNode(const std::string& name);
XmlNode(XmlNode&&);
virtual ~XmlNode();
XmlNode& operator=(XmlNode&&);
/// Add a child element to this element.
/// @param child is an XmlNode to add as a child for this element.
/// @return true on success, false otherwise.
[[nodiscard]] bool AddChild(XmlNode child);
/// Adds Elements to this node using the Element struct.
[[nodiscard]] bool AddElements(const std::vector<Element>& elements);
/// Set a string attribute.
/// @param attribute_name The name (lhs) of the attribute.
/// @param attribute The value (rhs) of the attribute.
[[nodiscard]] bool SetStringAttribute(const std::string& attribute_name,
const std::string& attribute);
/// Sets an integer attribute.
/// @param attribute_name The name (lhs) of the attribute.
/// @param number The value (rhs) of the attribute.
[[nodiscard]] bool SetIntegerAttribute(const std::string& attribute_name,
uint64_t number);
/// Set a floating point number attribute.
/// @param attribute_name is the name of the attribute to set.
/// @param number is the value (rhs) of the attribute.
[[nodiscard]] bool SetFloatingPointAttribute(
const std::string& attribute_name,
double number);
/// Sets 'id=@a id' attribute.
/// @param id is the ID for this element.
[[nodiscard]] bool SetId(uint32_t id);
/// Similar to SetContent, but appends to the end of existing content.
void AddContent(const std::string& content);
/// Set the contents of an XML element using a string.
/// This cannot set child elements because <> will become &lt; and &rt;
/// This should be used to set the text for the element, e.g. setting
/// a URL for <BaseURL> element.
/// @param content is a string containing the text-encoded child elements to
/// be added to the element.
void SetContent(const std::string& content);
/// @return namespaces used in the node and its descendents.
std::set<std::string> ExtractReferencedNamespaces() const;
/// @param comment The body of a comment to add to the top of the XML.
/// @return A string containing the XML.
std::string ToString(const std::string& comment) const;
/// Gets the attribute with the given name.
/// @param name The name of the attribute to get.
/// @param value [OUT] where to put the resulting value.
/// @return True if the attribute exists, false if not.
bool GetAttribute(const std::string& name, std::string* value) const;
private:
friend bool shaka::XmlEqual(const std::string& xml1,
const xml::XmlNode& xml2);
xmlNode* GetRawPtr() const;
// Don't use xmlNode directly so we don't have to forward-declare a bunch of
// libxml types to define the scoped_xml_ptr type. This allows us to only
// include libxml headers in a few source files.
class Impl;
std::unique_ptr<Impl> impl_;
DISALLOW_COPY_AND_ASSIGN(XmlNode);
};
/// This corresponds to RepresentationBaseType in MPD. RepresentationBaseType is
/// not a concrete element type so this should not get instantiated on its own.
/// AdaptationSet and Representation are subtypes of this.
class RepresentationBaseXmlNode : public XmlNode {
public:
~RepresentationBaseXmlNode() override;
[[nodiscard]] bool AddContentProtectionElements(
const std::list<ContentProtectionElement>& content_protection_elements);
/// @param scheme_id_uri is content of the schemeIdUri attribute.
/// @param value is the content of value attribute.
[[nodiscard]] bool AddSupplementalProperty(const std::string& scheme_id_uri,
const std::string& value);
/// @param scheme_id_uri is content of the schemeIdUri attribute.
/// @param value is the content of value attribute.
[[nodiscard]] bool AddEssentialProperty(const std::string& scheme_id_uri,
const std::string& value);
protected:
explicit RepresentationBaseXmlNode(const std::string& name);
/// Add a Descriptor.
/// @param descriptor_name is the name of the descriptor.
/// @param scheme_id_uri is content of the schemeIdUri attribute.
/// @param value is the content of value attribute.
[[nodiscard]] bool AddDescriptor(const std::string& descriptor_name,
const std::string& scheme_id_uri,
const std::string& value);
private:
[[nodiscard]] bool AddContentProtectionElement(
const ContentProtectionElement& content_protection_element);
DISALLOW_COPY_AND_ASSIGN(RepresentationBaseXmlNode);
};
/// AdaptationSetType specified in MPD.
class AdaptationSetXmlNode : public RepresentationBaseXmlNode {
public:
AdaptationSetXmlNode();
~AdaptationSetXmlNode() override;
/// @param scheme_id_uri is content of the schemeIdUri attribute.
/// @param value is the content of value attribute.
[[nodiscard]] bool AddAccessibilityElement(const std::string& scheme_id_uri,
const std::string& value);
/// @param scheme_id_uri is content of the schemeIdUri attribute.
/// @param value is the content of value attribute.
[[nodiscard]] bool AddRoleElement(const std::string& scheme_id_uri,
const std::string& value);
/// @param value is element's content.
[[nodiscard]] bool AddLabelElement(const std::string& value);
private:
DISALLOW_COPY_AND_ASSIGN(AdaptationSetXmlNode);
};
/// RepresentationType in MPD.
class RepresentationXmlNode : public RepresentationBaseXmlNode {
public:
RepresentationXmlNode();
~RepresentationXmlNode() override;
/// Adds video metadata to the MPD.
/// @param video_info constains the VideoInfo for a Representation.
/// @param set_width is a flag for setting the width attribute.
/// @param set_height is a flag for setting the height attribute.
/// @param set_frame_rate is a flag for setting the frameRate attribute.
/// @return true if successfully set attributes and children elements (if
/// applicable), false otherwise.
[[nodiscard]] bool AddVideoInfo(const MediaInfo::VideoInfo& video_info,
bool set_width,
bool set_height,
bool set_frame_rate);
/// Adds audio metadata to the MPD.
/// @param audio_info constains the AudioInfos for a Representation.
/// @return true if successfully set attributes and children elements (if
/// applicable), false otherwise.
[[nodiscard]] bool AddAudioInfo(const MediaInfo::AudioInfo& audio_info);
/// Adds fields that are specific to VOD. This ignores @a media_info fields
/// for Live.
/// @param media_info is a MediaInfo with VOD information.
/// @param use_segment_list is a param that instructs the xml writer to
/// use SegmentList instead of SegmentBase.
/// @param target_segment_duration is a param that specifies the target
// duration of media segments. This is only used when use_segment_list
// is true.
/// @return true on success, false otherwise.
[[nodiscard]] bool AddVODOnlyInfo(const MediaInfo& media_info,
bool use_segment_list,
double target_segment_duration);
/// @param segment_infos is a set of SegmentInfos. This method assumes that
/// SegmentInfos are sorted by its start time.
[[nodiscard]] bool AddLiveOnlyInfo(
const MediaInfo& media_info,
const std::list<SegmentInfo>& segment_infos,
bool low_latency_dash_mode);
private:
// Add AudioChannelConfiguration element. Note that it is a required element
// for audio Representations.
[[nodiscard]] bool AddAudioChannelInfo(
const MediaInfo::AudioInfo& audio_info);
// Add audioSamplingRate attribute to this element, if present.
[[nodiscard]] bool AddAudioSamplingRateInfo(
const MediaInfo::AudioInfo& audio_info);
DISALLOW_COPY_AND_ASSIGN(RepresentationXmlNode);
};
} // namespace xml
} // namespace shaka
#endif // MPD_BASE_XML_XML_NODE_H_