From 86f43cd8d60f1b64bee987432bf037edc925988e Mon Sep 17 00:00:00 2001
From: Sergey Lyubka <valenok@gmail.com>
Date: Fri, 6 Aug 2021 10:23:08 +0100
Subject: [PATCH] Refactor mg_socketpair and document
 MG_ENABLE_NATIVE_SOCKETPAIR

---
 docs/README.md |  1 +
 mongoose.c     | 13 +++++++------
 mongoose.h     |  4 ++++
 src/config.h   |  4 ++++
 src/sock.c     | 13 +++++++------
 5 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/docs/README.md b/docs/README.md
index f6dc17b6..c708c5b7 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -241,6 +241,7 @@ Here is a list of build constants and their default values:
 |MG_ENABLE_LOG | 1 | Enable `LOG()` macro |
 |MG_ENABLE_MD5 | 0 | Use native MD5 implementation |
 |MG_ENABLE_SOCKETPAIR | 0 | Enable `mg_socketpair()` for multi-threading |
+|MG_ENABLE_NATIVE_SOCKETPAIR | 0 | Use native `socketpair()` syscall for `mg_socketpair()`|
 |MG_ENABLE_SSI | 1 | Enable serving SSI files by `mg_http_serve_dir()` |
 |MG_ENABLE_DIRLIST | 0 | Enable directory listing |
 |MG_ENABLE_CUSTOM_RANDOM | 0 | Provide custom RNG function `mg_random()` |
diff --git a/mongoose.c b/mongoose.c
index 65cf7076..84deb1ad 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -2855,8 +2855,8 @@ typedef Socket_t SOCKET;
 typedef int SOCKET;
 #endif
 
-#define FD(c_) ((SOCKET)(size_t)(c_)->fd)
-#define S2PTR(s_) ((void *) (size_t)(s_))
+#define FD(c_) ((SOCKET) (size_t) (c_)->fd)
+#define S2PTR(s_) ((void *) (size_t) (s_))
 
 #ifndef MSG_NONBLOCKING
 #define MSG_NONBLOCKING 0
@@ -3231,9 +3231,8 @@ static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
   }
 }
 
-#if MG_ENABLE_SOCKETPAIR
 bool mg_socketpair(int *s1, int *s2) {
-#ifdef MG_ENABLE_NATIVE_SOCKETPAIR
+#if MG_ENABLE_NATIVE_SOCKETPAIR
   // For some reason, native socketpair() call fails on Macos
   // Enable this codepath only when MG_ENABLE_NATIVE_SOCKETPAIR is defined
   int sp[2], ret = 0;
@@ -3242,7 +3241,7 @@ bool mg_socketpair(int *s1, int *s2) {
   }
   LOG(LL_INFO, ("errno %d", errno));
   return ret;
-#else
+#elif MG_ENABLE_SOCKETPAIR
   union usa sa, sa2;
   SOCKET sp[2] = {INVALID_SOCKET, INVALID_SOCKET};
   socklen_t len = sizeof(sa.sin);
@@ -3269,9 +3268,11 @@ bool mg_socketpair(int *s1, int *s2) {
   }
 
   return ret;
+#else
+  *s1 = *s2 = INVALID_SOCKET;
+  return false;
 #endif
 }
-#endif
 
 struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
                                 mg_event_handler_t fn, void *fn_data) {
diff --git a/mongoose.h b/mongoose.h
index 0fe9e93a..e25c10b5 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -66,6 +66,10 @@ extern "C" {
 #define MG_ENABLE_SOCKETPAIR 0
 #endif
 
+#ifndef MG_ENABLE_NATIVE_SOCKETPAIR
+#define MG_ENABLE_NATIVE_SOCKETPAIR 0
+#endif
+
 #ifndef MG_ENABLE_CUSTOM_RANDOM
 #define MG_ENABLE_CUSTOM_RANDOM 0
 #endif
diff --git a/src/config.h b/src/config.h
index d1f52ed4..32f06f82 100644
--- a/src/config.h
+++ b/src/config.h
@@ -41,6 +41,10 @@
 #define MG_ENABLE_SOCKETPAIR 0
 #endif
 
+#ifndef MG_ENABLE_NATIVE_SOCKETPAIR
+#define MG_ENABLE_NATIVE_SOCKETPAIR 0
+#endif
+
 #ifndef MG_ENABLE_CUSTOM_RANDOM
 #define MG_ENABLE_CUSTOM_RANDOM 0
 #endif
diff --git a/src/sock.c b/src/sock.c
index 4fda912d..678e3a2c 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -28,8 +28,8 @@ typedef Socket_t SOCKET;
 typedef int SOCKET;
 #endif
 
-#define FD(c_) ((SOCKET)(size_t)(c_)->fd)
-#define S2PTR(s_) ((void *) (size_t)(s_))
+#define FD(c_) ((SOCKET) (size_t) (c_)->fd)
+#define S2PTR(s_) ((void *) (size_t) (s_))
 
 #ifndef MSG_NONBLOCKING
 #define MSG_NONBLOCKING 0
@@ -404,9 +404,8 @@ static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
   }
 }
 
-#if MG_ENABLE_SOCKETPAIR
 bool mg_socketpair(int *s1, int *s2) {
-#ifdef MG_ENABLE_NATIVE_SOCKETPAIR
+#if MG_ENABLE_NATIVE_SOCKETPAIR
   // For some reason, native socketpair() call fails on Macos
   // Enable this codepath only when MG_ENABLE_NATIVE_SOCKETPAIR is defined
   int sp[2], ret = 0;
@@ -415,7 +414,7 @@ bool mg_socketpair(int *s1, int *s2) {
   }
   LOG(LL_INFO, ("errno %d", errno));
   return ret;
-#else
+#elif MG_ENABLE_SOCKETPAIR
   union usa sa, sa2;
   SOCKET sp[2] = {INVALID_SOCKET, INVALID_SOCKET};
   socklen_t len = sizeof(sa.sin);
@@ -442,9 +441,11 @@ bool mg_socketpair(int *s1, int *s2) {
   }
 
   return ret;
+#else
+  *s1 = *s2 = INVALID_SOCKET;
+  return false;
 #endif
 }
-#endif
 
 struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
                                 mg_event_handler_t fn, void *fn_data) {