Implementing MG interfaces

PUBLISHED_FROM=46496c2d5340a0bbe4fe1c6c9ff187bc65d2d35f

docs/c-api/net.h/intro.md

@@ -15,6 +15,7 @@ items:
   - { name: mg_enable_multithreading.md }
   - { name: mg_mgr_free.md }
   - { name: mg_mgr_init.md }
+  - { name: mg_mgr_init_opt.md }
   - { name: mg_mgr_poll.md }
   - { name: mg_next.md }
   - { name: mg_printf.md }
@@ -31,6 +32,7 @@ items:
   - { name: struct_mg_connect_opts.md }
   - { name: struct_mg_connection.md }
   - { name: struct_mg_mgr.md }
+  - { name: struct_mg_mgr_init_opts.md }
   - { name: struct_mg_multithreading_opts.md }
 ---
 

docs/c-api/net.h/mg_event_handler_t.md

@@ -3,7 +3,8 @@ title: "mg_event_handler_t"
 decl_name: "mg_event_handler_t"
 symbol_kind: "typedef"
 signature: |
-  typedef void (*mg_event_handler_t)(struct mg_connection *nc, int ev, void *ev_data);
+  typedef void (*mg_event_handler_t)(struct mg_connection *nc, int ev,
+                                     void *ev_data);
 ---
 
 Callback function (event handler) prototype. Must be defined by the user.

docs/c-api/net.h/mg_mgr_init_opt.md

@@ -0,0 +1,14 @@
+---
+title: "mg_mgr_init_opt()"
+decl_name: "mg_mgr_init_opt"
+symbol_kind: "func"
+signature: |
+  void mg_mgr_init_opt(struct mg_mgr *mgr, void *user_data,
+                       struct mg_mgr_init_opts opts);
+---
+
+Like `mg_mgr_init` but with more options.
+
+Notably, this allows you to create a manger and choose
+dynamically which networking interface implementation to use. 
+

docs/c-api/net.h/struct_mg_connection.md

@@ -42,6 +42,7 @@ signature: |
     } priv_1;       /* Used by mg_enable_multithreading() */
     void *priv_2;   /* Used by mg_enable_multithreading() */
     void *mgr_data; /* Implementation-specific event manager's data. */
+    struct mg_iface *iface;
     unsigned long flags;
   /* Flags set by Mongoose */
   #define MG_F_LISTENING (1 << 0)          /* This connection is listening */

docs/c-api/net.h/struct_mg_mgr.md

@@ -12,7 +12,8 @@ signature: |
     sock_t ctl[2]; /* Socketpair for mg_broadcast() */
   #endif
     void *user_data; /* User data */
-    void *mgr_data;  /* Implementation-specific event manager's data. */
+    int num_ifaces;
+    struct mg_iface **ifaces; /* network interfaces */
   #if MG_ENABLE_JAVASCRIPT
     struct v7 *v7;
   #endif

docs/c-api/net.h/struct_mg_mgr_init_opts.md

@@ -0,0 +1,26 @@
+---
+title: "struct mg_mgr_init_opts"
+decl_name: "struct mg_mgr_init_opts"
+symbol_kind: "struct"
+signature: |
+  struct mg_mgr_init_opts {
+    struct mg_iface_vtable *main_iface;
+    int num_ifaces;
+    struct mg_iface_vtable **ifaces;
+  };
+---
+
+Optional parameters to `mg_mgr_init_opt()`.
+
+If `main_iface` is not NULL, it will be used as the main interface in the
+default interface set. The pointer will be free'd by `mg_mgr_free`.
+Otherwise, the main interface will be autodetected based on the current
+platform.
+
+If `num_ifaces` is 0 and `ifaces` is NULL, the default interface set will be
+used.
+This is an advanced option, as it requires you to construct a full interface
+set, including special networking interfaces required by some optional
+features such as TCP tunneling. Memory backing `ifaces` and each of the
+`num_ifaces` pointers it contains will be reclaimed by `mg_mgr_free`. 
+