Encapsulate pending_fn and extra_data_handler_fn

Define 2 macros to encapsulate setting of pending_fn and
extra_data_handler_fn.

Also adding comments for both macros for clarity

Author: ExtremeGTX

subsys/usb/device_next/class/usbd_mtp_class.c

@@ -133,6 +133,18 @@ LOG_MODULE_REGISTER(usb_mtp_impl, CONFIG_USBD_MTP_LOG_LEVEL);
 	IF_ENABLED(DT_PROP(node_id, mtp_enabled),                                                  \
 		   ({.mountpoint = DT_PROP(node_id, mount_point), .files_count = 1, .read_only = DT_PROP(node_id, read_only)},))
 
+/* Used by MTP commands which reply to host over multiple packets
+ * like GetObject (Sending file to host) or a command sending its result
+ * in a separate packet
+ */
+#define DEV_TO_HOST_SET_PENDING_PACKET(ctx, fn) ctx->pending_fn = fn
+
+/* Used by MTP commands which receive data from host over multiple packets
+ * like SendObject (Receiving file from host) or a command receiving all required
+ * info over multiple packets like SendObjectInfo
+ */
+#define HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx, fn) ctx->extra_data_fn = fn
+
 /* Types */
 enum mtp_container_type {
 	MTP_CONTAINER_UNDEFINED = 0x00,
@@ -422,6 +434,19 @@ const char *mtp_code_to_string(uint16_t code)
 	return str;
 }
 #endif
+int mtp_get_pending_packet(struct mtp_context* ctx, struct net_buf *buf)
+{
+	if (ctx->pending_fn) {
+		return ctx->pending_fn(ctx, buf);
+	} else {
+		return -EINVAL;
+	}
+}
+
+bool mtp_packet_pending(struct mtp_context* ctx)
+{
+	return (ctx->pending_fn != NULL);
+}
 
 static void net_buf_add_utf16le(struct net_buf *buf, const char *str)
 {
@@ -443,20 +468,6 @@ static void net_buf_pull_utf16le(struct net_buf *buf, char *strbuf, size_t len)
 	}
 }
 
-int mtp_get_pending_packet(struct mtp_context* ctx, struct net_buf *buf)
-{
-	if (ctx->pending_fn) {
-		return ctx->pending_fn(ctx, buf);
-	} else {
-		return -EINVAL;
-	}
-}
-
-bool mtp_packet_pending(struct mtp_context* ctx)
-{
-	return (ctx->pending_fn != NULL);
-}
-
 static void data_header_push(struct net_buf *buf, struct mtp_container *mtp_command, uint32_t data_len)
 {
 	/* DATA Block Header */
@@ -627,7 +638,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_DEVICE_INFO)
 	/* Add the Packet Header */
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 MTP_CMD_HANDLER(MTP_OP_OPEN_SESSION)
@@ -712,7 +723,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_STORAGE_INFO)
 	/* Add the Packet Header */
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 MTP_CMD_HANDLER(MTP_OP_GET_STORAGE_IDS)
@@ -727,7 +738,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_STORAGE_IDS)
 	/* Add the Packet Header */
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 MTP_CMD_HANDLER(MTP_OP_GET_OBJECT_HANDLES)
@@ -755,7 +766,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_OBJECT_HANDLES)
 	/* Add the Packet Header */
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 MTP_CMD_HANDLER(MTP_OP_GET_OBJECT_INFO)
@@ -827,7 +838,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_OBJECT_INFO)
 	/* Add the Packet Header */
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 static int continue_get_object(struct mtp_context* ctx, struct net_buf *buf)
@@ -858,10 +869,10 @@ static int continue_get_object(struct mtp_context* ctx, struct net_buf *buf)
 			LOG_DBG("Done (%u), CONFIRMING", read);
 			fs_close(&ctx->filestate.file);
 			memset(&ctx->filestate, 0x00, sizeof(ctx->filestate));
-			ctx->pending_fn = mtp_send_confirmation;
+			DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 		} else {
 			LOG_DBG("Continue (%u) Next", read);
-			ctx->pending_fn = continue_get_object;
+			DEV_TO_HOST_SET_PENDING_PACKET(ctx, continue_get_object);
 		}
 	} else {
 		LOG_ERR("Shouldn't happen");
@@ -927,7 +938,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_OBJECT)
 		ctx->cmd = MTP_OP_GET_OBJECT;
 		ctx->filestate.total_size = filesize;
 		ctx->filestate.transferred = read;
-		ctx->pending_fn = continue_get_object;
+		DEV_TO_HOST_SET_PENDING_PACKET(ctx, continue_get_object);
 	} else {
 		int read = fs_read(&ctx->filestate.file, ctx->filebuf, filesize);
 
@@ -938,7 +949,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_OBJECT)
 
 		fs_close(&ctx->filestate.file);
 		memset(&ctx->filestate, 0x00, sizeof(ctx->filestate));
-		ctx->pending_fn = mtp_send_confirmation;
+		DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 	}
 }
 
@@ -1118,12 +1129,12 @@ static int continue_send_object(struct mtp_context* ctx, struct net_buf *buf_in)
 		LOG_DBG("Sending Confirmation after reciving data (Total len: %u)",
 			ctx->filestate.transferred);
 
-		ctx->extra_data_fn = NULL;
+		HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx,  NULL);
 		memset(&ctx->filestate, 0x00, sizeof(ctx->filestate));
-		ctx->pending_fn = mtp_send_confirmation;
+		DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 		return 1;
 	} else {
-		ctx->extra_data_fn = continue_send_object;
+		HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx,  continue_send_object);
 		return 0;
 	}
 }
@@ -1149,10 +1160,10 @@ MTP_CMD_HANDLER(MTP_OP_SEND_OBJECT)
 				ctx->filestate.transferred);
 
 			memset(&ctx->filestate, 0x00, sizeof(ctx->filestate));
-			ctx->extra_data_fn = NULL;
+			HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx,  NULL);
 			mtp_send_confirmation(ctx, buf);
 		} else {
-			ctx->extra_data_fn = continue_send_object;
+			HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx,  continue_send_object);
 		}
 	}
 }
@@ -1205,7 +1216,7 @@ MTP_CMD_HANDLER(MTP_OP_GET_OBJECT_REFERENCES)
 
 	data_header_push(buf, mtp_command, buf->len);
 
-	ctx->pending_fn = mtp_send_confirmation;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, mtp_send_confirmation);
 }
 
 /*
@@ -1240,6 +1251,7 @@ int mtp_commands_handler(struct mtp_context* ctx, struct net_buf *buf_in, struct
 		}
 	}
 
+	ctx->cmd = mtp_command->hdr.code;
 	LOG_DBG(GREEN "[%s]" RESET, mtp_code_to_string(mtp_command->hdr.code));
 
 	switch (mtp_command->hdr.code) {
@@ -1330,8 +1342,8 @@ int mtp_control_handler(struct mtp_context* ctx, uint8_t request, struct net_buf
 				memset(ctx->filebuf, 0x00, sizeof(ctx->filebuf));
 				memset(&ctx->filestate, 0x00, sizeof(ctx->filestate));
 			}
-			ctx->pending_fn = NULL;
-			ctx->extra_data_fn = NULL;
+			DEV_TO_HOST_SET_PENDING_PACKET(ctx, NULL);
+			HOST_TO_DEV_SET_CONT_DATA_HANDLER(ctx,  NULL);
 
 			canceled = true;
 			break;
@@ -1367,7 +1379,7 @@ static int mtp_send_confirmation(struct mtp_context* ctx, struct net_buf *buf)
 		LOG_ERR("Failed to send MTP confirmation");
 	}
 
-	ctx->pending_fn = NULL;
+	DEV_TO_HOST_SET_PENDING_PACKET(ctx, NULL);
 	return 0;
 }