Add (empty) setSocketOptions() to allow setting QoS.

Author: danieleggert

CoreFoundation/URL.subproj/CFURLSessionInterface.c

@@ -85,6 +85,9 @@ CFURLSession_EasyCode CFURLSession_easy_setopt_wc(CFURLSessionEasyHandle _Nonnul
 CFURLSession_EasyCode CFURLSession_easy_setopt_dc(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, int(*_Nullable a)(CFURLSessionEasyHandle _Nonnull handle, CFURLSession_Info type, char *_Nonnull data, size_t size, void *_Nullable userptr)) {
     return (CFURLSession_EasyCode) curl_easy_setopt(curl, option, a);
 }
+CFURLSession_EasyCode CFURLSession_easy_setopt_sc(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, CFURLSessionSocketOptionCallback * _Nullable a) {
+    return (CFURLSession_EasyCode) curl_easy_setopt(curl, option, a);
+}
 CFURLSession_EasyCode CFURLSession_easy_getinfo_long(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Info info, long *_Nonnull a) {
     return (CFURLSession_EasyCode) curl_easy_getinfo(curl, info, a);
 }

CoreFoundation/URL.subproj/CFURLSessionInterface.h

@@ -716,6 +716,13 @@ CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_setopt_int(CFURLSessionEasyHan
 CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_setopt_long(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, long a);
 CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_setopt_wc(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, size_t(*_Nullable a)(char *_Nonnull, size_t, size_t, void *_Nullable));
 CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_setopt_dc(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, int(*_Nullable a)(CFURLSessionEasyHandle _Nonnull handle, CFURLSession_Info type, char *_Nonnull data, size_t size, void *_Nullable userptr));
+typedef enum {
+    CFURLSessionSocketTypeIPCXN,  // socket created for a specific IP connection
+    CFURLSessionSocketTypeAccept, // socket created by accept() call
+} CFURLSessionSocketType;
+typedef int (CFURLSessionSocketOptionCallback)(void *clientp, int fd, CFURLSessionSocketType purpose);
+CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_setopt_sc(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Option option, CFURLSessionSocketOptionCallback * _Nullable a);
+
 CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_getinfo_long(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Info info, long *_Nonnull a);
 CF_EXPORT CFURLSession_EasyCode CFURLSession_easy_getinfo_charp(CFURLSessionEasyHandle _Nonnull curl, CFURLSession_Info info, char *_Nonnull*_Nonnull a);
 

Foundation/NSURLSession+libcurl.swift

@@ -1202,6 +1202,18 @@ private extension NSURLSessionTask.EasyHandle {
             let handle = Unmanaged<NSURLSessionTask.EasyHandle>.fromOpaque(userdata).takeUnretainedValue()
             return handle.didReceiveHeaderData(data, size: size, nmemb: nmemb)
             }.asError()
+        // socket options
+        try! CFURLSession_easy_setopt_ptr(rawHandle, CFURLSession_OptionSOCKOPTDATA, UnsafeMutablePointer<Void>(unsafeAddress(of: self))).asError()
+        try! CFURLSession_easy_setopt_sc(rawHandle, CFURLSession_OptionSOCKOPTFUNCTION) { (data: UnsafeMutablePointer<Void>, fd: CInt, type: CFURLSessionSocketType) -> CInt in
+            let handle = Unmanaged<NSURLSessionTask.EasyHandle>.fromOpaque(data).takeUnretainedValue()
+            guard type == CFURLSessionSocketTypeIPCXN else { return 0 }
+            do {
+                try handle.setSocketOptions(fd)
+                return 0
+            } catch {
+                return 1
+            }
+            }.asError()
     }
     /// This callback function gets called by libcurl when it receives body
     /// data.
@@ -1248,6 +1260,20 @@ private extension NSURLSessionTask.EasyHandle {
         }
         return Int(CFURLSessionReadFuncAbort)
     }
+    
+    func setSocketOptions(fd: CInt) throws {
+        //TODO: At this point we should call setsockopt(2) to set the QoS on
+        // the socket based on the QoS of the request.
+        //
+        // On Linux this can be done with IP_TOS. But there's both IntServ and
+        // DiffServ.
+        //
+        // Not sure what Darwin uses.
+        //
+        // C.f.:
+        //     <https://en.wikipedia.org/wiki/Type_of_service>
+        //     <https://en.wikipedia.org/wiki/Quality_of_service>
+    }
 }
 
 extension NSURLSessionTask.EasyHandle {