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TMessagesProj/jni/voip/webrtc/api/jsep.h

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+/*
+ *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// This file contains declarations of interfaces that wrap SDP-related
+// constructs; session descriptions and ICE candidates. The inner "cricket::"
+// objects shouldn't be accessed directly; the intention is that an application
+// using the PeerConnection API only creates these objects from strings, and
+// them passes them into the PeerConnection.
+//
+// Though in the future, we're planning to provide an SDP parsing API, with a
+// structure more friendly than cricket::SessionDescription.
+
+#ifndef API_JSEP_H_
+#define API_JSEP_H_
+
+#include <stddef.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/ref_count.h"
+#include "api/rtc_error.h"
+#include "rtc_base/system/rtc_export.h"
+
+namespace cricket {
+class Candidate;
+class SessionDescription;
+}  // namespace cricket
+
+namespace webrtc {
+
+struct SdpParseError {
+ public:
+  // The sdp line that causes the error.
+  std::string line;
+  // Explains the error.
+  std::string description;
+};
+
+// Class representation of an ICE candidate.
+//
+// An instance of this interface is supposed to be owned by one class at
+// a time and is therefore not expected to be thread safe.
+//
+// An instance can be created by CreateIceCandidate.
+class RTC_EXPORT IceCandidateInterface {
+ public:
+  virtual ~IceCandidateInterface() {}
+  // If present, this is the value of the "a=mid" attribute of the candidate's
+  // m= section in SDP, which identifies the m= section.
+  virtual std::string sdp_mid() const = 0;
+  // This indicates the index (starting at zero) of m= section this candidate
+  // is associated with. Needed when an endpoint doesn't support MIDs.
+  virtual int sdp_mline_index() const = 0;
+  // Only for use internally.
+  virtual const cricket::Candidate& candidate() const = 0;
+  // The URL of the ICE server which this candidate was gathered from.
+  // TODO(zhihuang): Remove the default implementation once the subclasses
+  // implement this method.
+  virtual std::string server_url() const;
+  // Creates a SDP-ized form of this candidate.
+  virtual bool ToString(std::string* out) const = 0;
+};
+
+// Creates a IceCandidateInterface based on SDP string.
+// Returns null if the sdp string can't be parsed.
+// `error` may be null.
+RTC_EXPORT IceCandidateInterface* CreateIceCandidate(const std::string& sdp_mid,
+                                                     int sdp_mline_index,
+                                                     const std::string& sdp,
+                                                     SdpParseError* error);
+
+// Creates an IceCandidateInterface based on a parsed candidate structure.
+RTC_EXPORT std::unique_ptr<IceCandidateInterface> CreateIceCandidate(
+    const std::string& sdp_mid,
+    int sdp_mline_index,
+    const cricket::Candidate& candidate);
+
+// This class represents a collection of candidates for a specific m= section.
+// Used in SessionDescriptionInterface.
+class IceCandidateCollection {
+ public:
+  virtual ~IceCandidateCollection() {}
+  virtual size_t count() const = 0;
+  // Returns true if an equivalent `candidate` exist in the collection.
+  virtual bool HasCandidate(const IceCandidateInterface* candidate) const = 0;
+  virtual const IceCandidateInterface* at(size_t index) const = 0;
+};
+
+// Enum that describes the type of the SessionDescriptionInterface.
+// Corresponds to RTCSdpType in the WebRTC specification.
+// https://w3c.github.io/webrtc-pc/#dom-rtcsdptype
+enum class SdpType {
+  kOffer,     // Description must be treated as an SDP offer.
+  kPrAnswer,  // Description must be treated as an SDP answer, but not a final
+              // answer.
+  kAnswer,    // Description must be treated as an SDP final answer, and the
+              // offer-answer exchange must be considered complete after
+              // receiving this.
+  kRollback   // Resets any pending offers and sets signaling state back to
+              // stable.
+};
+
+// Returns the string form of the given SDP type. String forms are defined in
+// SessionDescriptionInterface.
+RTC_EXPORT const char* SdpTypeToString(SdpType type);
+
+// Returns the SdpType from its string form. The string form can be one of the
+// constants defined in SessionDescriptionInterface. Passing in any other string
+// results in nullopt.
+absl::optional<SdpType> SdpTypeFromString(const std::string& type_str);
+
+// Class representation of an SDP session description.
+//
+// An instance of this interface is supposed to be owned by one class at a time
+// and is therefore not expected to be thread safe.
+//
+// An instance can be created by CreateSessionDescription.
+class RTC_EXPORT SessionDescriptionInterface {
+ public:
+  // String representations of the supported SDP types.
+  static const char kOffer[];
+  static const char kPrAnswer[];
+  static const char kAnswer[];
+  static const char kRollback[];
+
+  virtual ~SessionDescriptionInterface() {}
+
+  // Create a new SessionDescriptionInterface object
+  // with the same values as the old object.
+  // TODO(bugs.webrtc.org:12215): Remove default implementation
+  virtual std::unique_ptr<SessionDescriptionInterface> Clone() const {
+    return nullptr;
+  }
+
+  // Only for use internally.
+  virtual cricket::SessionDescription* description() = 0;
+  virtual const cricket::SessionDescription* description() const = 0;
+
+  // Get the session id and session version, which are defined based on
+  // RFC 4566 for the SDP o= line.
+  virtual std::string session_id() const = 0;
+  virtual std::string session_version() const = 0;
+
+  // Returns the type of this session description as an SdpType. Descriptions of
+  // the various types are found in the SdpType documentation.
+  // TODO(steveanton): Remove default implementation once Chromium has been
+  // updated.
+  virtual SdpType GetType() const;
+
+  // kOffer/kPrAnswer/kAnswer
+  // TODO(steveanton): Remove this in favor of `GetType` that returns SdpType.
+  virtual std::string type() const = 0;
+
+  // Adds the specified candidate to the description.
+  //
+  // Ownership is not transferred.
+  //
+  // Returns false if the session description does not have a media section
+  // that corresponds to `candidate.sdp_mid()` or
+  // `candidate.sdp_mline_index()`.
+  virtual bool AddCandidate(const IceCandidateInterface* candidate) = 0;
+
+  // Removes the candidates from the description, if found.
+  //
+  // Returns the number of candidates removed.
+  virtual size_t RemoveCandidates(
+      const std::vector<cricket::Candidate>& candidates);
+
+  // Returns the number of m= sections in the session description.
+  virtual size_t number_of_mediasections() const = 0;
+
+  // Returns a collection of all candidates that belong to a certain m=
+  // section.
+  virtual const IceCandidateCollection* candidates(
+      size_t mediasection_index) const = 0;
+
+  // Serializes the description to SDP.
+  virtual bool ToString(std::string* out) const = 0;
+};
+
+// Creates a SessionDescriptionInterface based on the SDP string and the type.
+// Returns null if the sdp string can't be parsed or the type is unsupported.
+// `error` may be null.
+// TODO(steveanton): This function is deprecated. Please use the functions below
+// which take an SdpType enum instead. Remove this once it is no longer used.
+RTC_EXPORT SessionDescriptionInterface* CreateSessionDescription(
+    const std::string& type,
+    const std::string& sdp,
+    SdpParseError* error);
+
+// Creates a SessionDescriptionInterface based on the SDP string and the type.
+// Returns null if the SDP string cannot be parsed.
+// If using the signature with `error_out`, details of the parsing error may be
+// written to `error_out` if it is not null.
+RTC_EXPORT std::unique_ptr<SessionDescriptionInterface>
+CreateSessionDescription(SdpType type, const std::string& sdp);
+RTC_EXPORT std::unique_ptr<SessionDescriptionInterface>
+CreateSessionDescription(SdpType type,
+                         const std::string& sdp,
+                         SdpParseError* error_out);
+
+// Creates a SessionDescriptionInterface based on a parsed SDP structure and the
+// given type, ID and version.
+std::unique_ptr<SessionDescriptionInterface> CreateSessionDescription(
+    SdpType type,
+    const std::string& session_id,
+    const std::string& session_version,
+    std::unique_ptr<cricket::SessionDescription> description);
+
+// CreateOffer and CreateAnswer callback interface.
+class RTC_EXPORT CreateSessionDescriptionObserver
+    : public webrtc::RefCountInterface {
+ public:
+  // This callback transfers the ownership of the `desc`.
+  // TODO(deadbeef): Make this take an std::unique_ptr<> to avoid confusion
+  // around ownership.
+  virtual void OnSuccess(SessionDescriptionInterface* desc) = 0;
+  // The OnFailure callback takes an RTCError, which consists of an
+  // error code and a string.
+  // RTCError is non-copyable, so it must be passed using std::move.
+  // Earlier versions of the API used a string argument. This version
+  // is removed; its functionality was the same as passing
+  // error.message.
+  virtual void OnFailure(RTCError error) = 0;
+
+ protected:
+  ~CreateSessionDescriptionObserver() override = default;
+};
+
+// SetLocalDescription and SetRemoteDescription callback interface.
+class RTC_EXPORT SetSessionDescriptionObserver
+    : public webrtc::RefCountInterface {
+ public:
+  virtual void OnSuccess() = 0;
+  // See description in CreateSessionDescriptionObserver for OnFailure.
+  virtual void OnFailure(RTCError error) = 0;
+
+ protected:
+  ~SetSessionDescriptionObserver() override = default;
+};
+
+}  // namespace webrtc
+
+#endif  // API_JSEP_H_