Add createOffer() and createAnswer()

DOC.md

@@ -207,7 +207,9 @@ Initiates the handshake process. Following this call, the local description call
 Arguments:
 
 - `pc`: the Peer Connection identifier
-- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for autodetection.
+- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for automatic (recommended).
+
+Warning: This function expects the optional type for the local description and not an SDP description. It is not possible to set an existing SDP description.
 
 #### rtcSetRemoteDescription
 
@@ -220,7 +222,8 @@ Sets the remote description received from the remote peer by the user's method o
 Arguments:
 
 - `pc`: the Peer Connection identifier
-- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for autodetection.
+- `sdp`: the remote description in SDP format
+- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for automatic (not recommended).
 
 If the remote description is an offer and `disableAutoNegotiation` was not set in `rtcConfiguration`, the library will automatically answer by calling `rtcSetLocalDescription` internally. Otherwise, the user must call it to answer the remote description.
 
@@ -296,7 +299,7 @@ Return value: the length of the string copied in buffer (including the terminati
 
 If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
-#### rtcGetRemoteDescription
+#### rtcGetRemoteDescriptionType
 
 ```
 int rtcGetRemoteDescriptionType(int pc, char *buffer, int size)
@@ -314,6 +317,22 @@ Return value: the length of the string copied in buffer (including the terminati
 
 If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
+#### rtcCreateOffer/rtcCreateAnswer
+
+```
+int rtcCreateOffer(int pc, char *buffer, int size)
+int rtcCreateAnswer(int pc, char *buffer, int size)
+```
+
+Create a local offer or answer description in SDP format. These functions are intended only for specific use cases where the application needs to generate a description without setting it. It is useless to call them before `rtcSetLocalDescription` as it doesn't expect the user to supply a description.
+
+- `pc`: the Peer Connection identifier
+- `buffer`: a user-supplied buffer to store the description
+- `size`: the size of `buffer`
+
+Return value: the length of the string copied in buffer (including the terminating null character) or a negative error code
+
+If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
 #### rtcGetLocalAddress
 

include/rtc/description.hpp

@@ -66,9 +66,10 @@ class RTC_CPP_EXPORT Description {
 	bool ended() const;
 
 	void hintType(Type type);
-	void setFingerprint(CertificateFingerprint f);
 	void addIceOption(string option);
 	void removeIceOption(const string &option);
+	void setIceAttribute(string ufrag, string pwd);
+	void setFingerprint(CertificateFingerprint f);
 
 	std::vector<string> attributes() const;
 	void addAttribute(string attr);

include/rtc/peerconnection.hpp

@@ -97,9 +97,13 @@ class RTC_CPP_EXPORT PeerConnection final : CheshireCat<impl::PeerConnection> {
 	bool getSelectedCandidatePair(Candidate *local, Candidate *remote);
 
 	void setLocalDescription(Description::Type type = Description::Type::Unspec, LocalDescriptionInit init = {});
+	void gatherLocalCandidates(std::vector<IceServer> additionalIceServers = {});
 	void setRemoteDescription(Description description);
 	void addRemoteCandidate(Candidate candidate);
-	void gatherLocalCandidates(std::vector<IceServer> additionalIceServers = {});
+
+	// For specific use cases only
+	Description createOffer();
+	Description createAnswer();
 
 	void setMediaHandler(shared_ptr<MediaHandler> handler);
 	shared_ptr<MediaHandler> getMediaHandler();

include/rtc/rtc.h

@@ -211,7 +211,7 @@ RTC_C_EXPORT int rtcSetIceStateChangeCallback(int pc, rtcIceStateChangeCallbackF
 RTC_C_EXPORT int rtcSetGatheringStateChangeCallback(int pc, rtcGatheringStateCallbackFunc cb);
 RTC_C_EXPORT int rtcSetSignalingStateChangeCallback(int pc, rtcSignalingStateCallbackFunc cb);
 
-RTC_C_EXPORT int rtcSetLocalDescription(int pc, const char *type);
+RTC_C_EXPORT int rtcSetLocalDescription(int pc, const char *type); // type may be NULL
 RTC_C_EXPORT int rtcSetRemoteDescription(int pc, const char *sdp, const char *type);
 RTC_C_EXPORT int rtcAddRemoteCandidate(int pc, const char *cand, const char *mid);
 
@@ -221,6 +221,10 @@ RTC_C_EXPORT int rtcGetRemoteDescription(int pc, char *buffer, int size);
 RTC_C_EXPORT int rtcGetLocalDescriptionType(int pc, char *buffer, int size);
 RTC_C_EXPORT int rtcGetRemoteDescriptionType(int pc, char *buffer, int size);
 
+// For specific use cases only
+RTC_C_EXPORT int rtcCreateOffer(int pc, char *buffer, int size);
+RTC_C_EXPORT int rtcCreateAnswer(int pc, char *buffer, int size);
+
 RTC_C_EXPORT int rtcGetLocalAddress(int pc, char *buffer, int size);
 RTC_C_EXPORT int rtcGetRemoteAddress(int pc, char *buffer, int size);
 

pages/content/pages/reference.md

@@ -210,7 +210,9 @@ Initiates the handshake process. Following this call, the local description call
 Arguments:
 
 - `pc`: the Peer Connection identifier
-- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for autodetection.
+- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for automatic (recommended).
+
+Warning: This function expects the optional type for the local description and not an SDP description. It is not possible to set an existing SDP description.
 
 #### rtcSetRemoteDescription
 
@@ -223,7 +225,8 @@ Sets the remote description received from the remote peer by the user's method o
 Arguments:
 
 - `pc`: the Peer Connection identifier
-- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for autodetection.
+- `sdp`: the remote description in SDP format
+- `type` (optional): type of the description ("offer", "answer", "pranswer", or "rollback") or NULL for automatic (not recommended).
 
 If the remote description is an offer and `disableAutoNegotiation` was not set in `rtcConfiguration`, the library will automatically answer by calling `rtcSetLocalDescription` internally. Otherwise, the user must call it to answer the remote description.
 
@@ -299,7 +302,7 @@ Return value: the length of the string copied in buffer (including the terminati
 
 If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
-#### rtcGetRemoteDescription
+#### rtcGetRemoteDescriptionType
 
 ```
 int rtcGetRemoteDescriptionType(int pc, char *buffer, int size)
@@ -317,6 +320,22 @@ Return value: the length of the string copied in buffer (including the terminati
 
 If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
+#### rtcCreateOffer/rtcCreateAnswer
+
+```
+int rtcCreateOffer(int pc, char *buffer, int size)
+int rtcCreateAnswer(int pc, char *buffer, int size)
+```
+
+Create a local offer or answer description in SDP format. These functions are intended only for specific use cases where the application needs to generate a description without setting it. It is useless to call them before `rtcSetLocalDescription` as it doesn't expect the user to supply a description.
+
+- `pc`: the Peer Connection identifier
+- `buffer`: a user-supplied buffer to store the description
+- `size`: the size of `buffer`
+
+Return value: the length of the string copied in buffer (including the terminating null character) or a negative error code
+
+If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
 #### rtcGetLocalAddress
 

src/capi.cpp

@@ -631,6 +631,24 @@ int rtcGetRemoteDescriptionType(int pc, char *buffer, int size) {
 	});
 }
 
+int rtcCreateOffer(int pc, char *buffer, int size) {
+	return wrap([&] {
+		auto peerConnection = getPeerConnection(pc);
+
+		auto desc = peerConnection->createOffer();
+		return copyAndReturn(string(desc), buffer, size);
+	});
+}
+
+int rtcCreateAnswer(int pc, char *buffer, int size) {
+	return wrap([&] {
+		auto peerConnection = getPeerConnection(pc);
+
+		auto desc = peerConnection->createAnswer();
+		return copyAndReturn(string(desc), buffer, size);
+	});
+}
+
 int rtcGetLocalAddress(int pc, char *buffer, int size) {
 	return wrap([&] {
 		auto peerConnection = getPeerConnection(pc);

src/description.cpp

@@ -216,6 +216,21 @@ void Description::hintType(Type type) {
 		mType = type;
 }
 
+void Description::addIceOption(string option) {
+	if (std::find(mIceOptions.begin(), mIceOptions.end(), option) == mIceOptions.end())
+		mIceOptions.emplace_back(std::move(option));
+}
+
+void Description::removeIceOption(const string &option) {
+	mIceOptions.erase(std::remove(mIceOptions.begin(), mIceOptions.end(), option),
+	                  mIceOptions.end());
+}
+
+void Description::setIceAttribute(string ufrag, string pwd) {
+	mIceUfrag = std::move(ufrag);
+	mIcePwd = std::move(pwd);
+}
+
 void Description::setFingerprint(CertificateFingerprint f) {
 	if (!f.isValid())
 		throw std::invalid_argument("Invalid " +
@@ -227,16 +242,6 @@ void Description::setFingerprint(CertificateFingerprint f) {
 	mFingerprint = std::move(f);
 }
 
-void Description::addIceOption(string option) {
-	if (std::find(mIceOptions.begin(), mIceOptions.end(), option) == mIceOptions.end())
-		mIceOptions.emplace_back(std::move(option));
-}
-
-void Description::removeIceOption(const string &option) {
-	mIceOptions.erase(std::remove(mIceOptions.begin(), mIceOptions.end(), option),
-	                  mIceOptions.end());
-}
-
 std::vector<string> Description::Entry::attributes() const { return mAttributes; }
 
 void Description::Entry::addAttribute(string attr) {