Add initial bits for an epoll-based echoserver test scenario

Makefile

@@ -22,6 +22,7 @@ pre:
 	mkdir -p obj/debug obj/release
 
 test: pre lib
+	for d in experiments/*; do echo "> $$d"; (cd $$d && make); done
 	for d in tests/*; do echo "> $$d"; (cd $$d && make run); done
 
 .PHONY: syntax lib test

experiments/epollecho/Makefile

@@ -0,0 +1,19 @@
+GPRBUILD=gprbuild
+GPRCLEAN=gprclean
+
+PROJECTGPR=echoserver.gpr
+
+build: pre
+	$(GPRBUILD) -p $(PROJECTGPR)
+
+syntax: pre lib
+	gnatmake -gnatc -gnat05 -P $(PROJECTGPR)
+
+clean: pre
+	$(GPRCLEAN) $(PROJECTGPR)
+	rm -rf ob
+
+pre:
+	mkdir -p obj
+
+.PHONY: syntax build

experiments/epollecho/callbacks.adb

@@ -0,0 +1,12 @@
+private with Ada.Text_IO;
+private with GNAT.Sockets;
+private with Async.Epoll;
+
+use Ada.Text_IO;
+use GNAT.Sockets;
+
+procedure Call_Me_Back (Sock : Socket_Type;  Ctx : Async.Epoll.Context_Type) is
+begin
+    Put_Line (">>> Starting Call_Me_Back");
+end Call_Me_Back;
+

experiments/epollecho/echo.adb

@@ -0,0 +1,14 @@
+with Ada.Text_IO,
+        GNAT.Sockets,
+        Async.Epoll;
+
+use Ada.Text_IO;
+
+package body Echo is
+    procedure Call_Me_Back (Sock : GNAT.Sockets.Socket_Type;
+                            Ctx : Async.Epoll.Context_Type) is
+    begin
+        Put_Line (">>> Starting Call_Me_Back");
+    end Call_Me_Back;
+end Echo;
+

experiments/epollecho/echo.ads

@@ -0,0 +1,7 @@
+with GNAT.Sockets;
+with Async.Epoll;
+
+package Echo is
+    procedure Call_Me_Back (Sock : GNAT.Sockets.Socket_Type;
+                        Ctx : Async.Epoll.Context_Type);
+end Echo;

experiments/epollecho/echoserver.adb

@@ -0,0 +1,67 @@
+--
+--  Echo server!
+
+private with Ada.Text_IO;
+private with Ada.Streams;
+private with GNAT.Sockets;
+private with Async.Epoll;
+private with Echo;
+
+use Ada.Text_IO;
+use Ada.Streams;
+use GNAT.Sockets;
+
+procedure echoserver is
+    ServerSock : Socket_Type;
+    ClientSock : Socket_Type;
+    ServerAddr : Sock_Addr_Type;
+
+    Listen_Addr : constant String := "127.0.0.1";
+    Listen_Port : constant Integer := 2046;
+
+    The_Hub : Async.Epoll.Hub := Async.Epoll.Create;
+
+begin
+    Initialize; -- Initialize the GNAT.Sockets library
+    ServerAddr.Addr := Inet_Addr (Listen_Addr);
+    ServerAddr.Port := Port_Type (Listen_Port);
+
+    Create_Socket (ServerSock);
+    Set_Socket_Option (ServerSock, Socket_Level, (Reuse_Address, True));
+    Put_Line (">>> Starting echo server on port" & Integer'Image (Listen_Port) & " ...");
+
+    Bind_Socket (ServerSock, ServerAddr);
+    Put_Line (".. bound to socket");
+
+    Listen_Socket (ServerSock);
+    Put_Line (".. listening for connections");
+
+    declare
+        Ctx : Async.Epoll.Callback_Tuple;
+    begin
+        The_Hub.Enable_Tracing;
+        Ctx.Callback := Echo.Call_Me_Back'Access;
+        Ctx.Socket := ServerSock;
+        The_Hub.Register (Ctx);
+    end;
+
+    loop
+        Accept_Socket (ServerSock, ClientSock, ServerAddr);
+        Put_Line (".. accepted connection");
+
+        declare
+            Channel : Stream_Access := Stream (ClientSock);
+            Char : Character;
+            Data : Ada.Streams.Stream_Element_Array (1 .. 1);
+            Offset : Ada.Streams.Stream_Element_Count;
+        begin
+            while true loop
+                Ada.Streams.Read (Channel.All, Data, Offset);
+                exit when Offset = 0;
+                Put (Character'Val (Data (1)));
+            end loop;
+            Put_Line (".. closing connection");
+            Close_Socket (ClientSock);
+        end;
+    end loop;
+end;

experiments/epollecho/echoserver.gpr

@@ -0,0 +1,14 @@
+
+project Echoserver is
+    for Languages use ("Ada");
+    for Source_Dirs use (".", "../../src");
+    for Object_Dir use "obj";
+    for Exec_Dir use ".";
+    for Main use ("echoserver.adb");
+
+    package Compiler is
+        for Default_Switches ("Ada") use
+                ("-g", "-gnat05");
+    end Compiler;
+end Echoserver;
+