From 6f5aa676b50178505c524c4aeece13fc33891497 Mon Sep 17 00:00:00 2001
From: Karchnu <karchnu@karchnu.fr>
Date: Wed, 1 Jul 2020 16:24:13 +0200
Subject: [PATCH] Low-level changes for poll(2) version of the LibIPC.

---
 src/ipc/lowlevel.cr | 81 ++++++++++++++++++++++++++-------------------
 1 file changed, 47 insertions(+), 34 deletions(-)

diff --git a/src/ipc/lowlevel.cr b/src/ipc/lowlevel.cr
index 6a6b0a7..ed483d6 100644
--- a/src/ipc/lowlevel.cr
+++ b/src/ipc/lowlevel.cr
@@ -2,16 +2,21 @@
 @[Link("ipc")]
 lib LibIPC
 	struct Connection
-		version :  LibC::UInt
-		index :    LibC::UInt
-		fd :       LibC::Int
 		type :     UInt8
 		spath :    LibC::Char* # [4096] # [PATH_MAX]
 	end
 
-	struct Connections
-		cinfos :   Connection**
-		size :     LibC::Int
+	struct Pollfd
+		fd :      LibC::Int
+		events :  LibC::Short
+		revents : LibC::Short
+	end
+
+	struct Ctx
+		cinfos :   Connection*
+		pollfd :   Pollfd*
+		tx :       Messages
+		size :     LibC::UInt64
 	end
 
 	struct Switching
@@ -31,11 +36,18 @@ lib LibIPC
 		LookUp
 	end
 
+	# Messages are stored in lists within the libipc before being sent.
+	struct Messages
+		messages :  Message*
+		size :      LibC::UInt64
+	end
+
 	struct Message
-		type :       UInt8
-		user_type :  UInt8
-		length :     LibC::UInt
-		payload :    LibC::Char*
+		type :       UInt8        # Internal message type.
+		user_type :  UInt8        # User-defined message type.
+		fd :         LibC::Int    # fd of the sender.
+		length :     LibC::UInt   # Payload length.
+		payload :    LibC::Char*  #
 	end
 
 	enum EventType
@@ -51,9 +63,10 @@ lib LibIPC
 	end
 
 	struct Event
-		type :     EventType
-		origin :   Connection*
-		message :  Message*
+		type :     EventType   #
+		index :    LibC::UInt  # Index of the sender in the ipc_ctx structure.
+		origin :   LibC::Int   # fd of the sender.
+		message :  Message*    # Pointer to the reveiced message.
 	end
 
 	struct IPCError
@@ -62,36 +75,33 @@ lib LibIPC
 		error_message : LibC::Char[8192]
 	end
 
-	fun ipc_server_init(env : LibC::Char**, connection : Connection*, sname : LibC::Char*) : IPCError
-	fun ipc_server_close(Connection*) : IPCError
-	fun ipc_close(Connection*) : IPCError
+	# Connection functions.
+	# Context is allocated, ipcd is requested and the connection/initialisation is performed.
+	fun ipc_server_init(ctx : Ctx*, sname : LibC::Char*) : IPCError
+	fun ipc_connection(Ctx*, LibC::Char*) : IPCError
 
-	# connection to a service
-	fun ipc_connection(LibC::Char**, Connection*, LibC::Char*) : IPCError
+	# Closing connections.
+	fun ipc_close(ctx : Ctx*, index : LibC::UInt64) : IPCError
+	fun ipc_close_all(ctx : Ctx*) # Void
 
-	fun ipc_read(Connection*, Message*) : IPCError
-	fun ipc_write(Connection*, Message*) : IPCError
+	fun ipc_ctx_free(Ctx*)        # Void
 
-	fun ipc_wait_event(Connections*, Connection*, Event*, LibC::Double*) : IPCError
+	# Loop function.
+	fun ipc_events_loop(Ctx*, Event*, LibC::UInt*) : IPCError
 
-	fun ipc_add(Connections*, Connection*) : IPCError
-	fun ipc_del(Connections*, Connection*) : IPCError
-	fun ipc_add_fd(Connections*, LibC::Int) : IPCError
-	fun ipc_del_fd(Connections*, LibC::Int) : IPCError
+	# Adding and removing file discriptors to read.
+	fun ipc_add(Ctx*, Connection*, Pollfd*) : IPCError
+	fun ipc_del(Ctx*, LibC::UInt) : IPCError
+	fun ipc_add_fd(Ctx*, LibC::Int) : IPCError
+	fun ipc_del_fd(Ctx*, LibC::Int) : IPCError
 
-	fun ipc_connection_gen(Connection*, LibC::UInt, LibC::UInt) : IPCError
-
-	fun ipc_connections_free(Connections*)  # Void
-	fun ipc_connections_close(Connections*) # Void
+	# Sending a message (will wait the fd to become available for IO operations).
+	fun ipc_write(Ctx*, Message*) : IPCError
 
 	# This function let the user get the default error message based on the error code.
 	# The error message is contained in the IPCError structure, this function should not be used, in most cases.
 	fun ipc_errors_get (LibC::Int) : LibC::Char*
 
-
-	# networkd-related functions
-	fun ipc_wait_event_networkd(Connections*, Connection*, Event*, Switchings*, LibC::Double*) : IPCError
-
 	fun ipc_receive_fd (sock : LibC::Int, fd : LibC::Int*) : IPCError
 	fun ipc_provide_fd (sock : LibC::Int, fd : LibC::Int ) : IPCError
 
@@ -100,7 +110,10 @@ lib LibIPC
 	fun ipc_switching_get  (switch : Switchings*, fd  : LibC::Int                 ) : LibC::Int
 	fun ipc_switching_free (switch : Switchings*                                  ) # Void
 
-	# non public functions (for testing purposes)
+	# non public functions
+	fun ipc_read(Ctx*, index : LibC::UInt, Message*) : IPCError
+
+	# for testing purposes
 	fun ipc_switching_print (switch : Switchings*) # Void
 	fun service_path (path : LibC::Char*, sname : LibC::Char*, index : Int32, version : Int32) : IPCError
 	fun ipc_connections_print (Connections*) # Void