1 files changed, 63 insertions, 2 deletions

diff --git a/src/isotp/receive.h b/src/isotp/receive.h
index 438d0824..e7e56d61 100644
--- a/src/isotp/receive.h
+++ b/src/isotp/receive.h
@@ -9,13 +9,74 @@
 extern "C" {
 #endif
 
-void isotp_complete_receive(IsoTpReceiveHandle* handle, IsoTpMessage* message);
+/* Public: A handle for beginning and continuing receiving a single ISO-TP
+ * message - both single and multi-frame.
+ *
+ * Since an ISO-TP message may contain multiple frames, we need to keep a handle
+ * around while waiting for subsequent CAN messages to complete the message.
+ * This struct encapsulates the local state required.
+ *
+ * completed - True if the received message request is completely finished.
+ * success - True if the message request was successful. The value if this field
+ *      isn't valid if 'completed' isn't true.
+ */
+typedef struct {
+    bool completed;
+    bool success;
 
-bool isotp_handle_single_frame(IsoTpReceiveHandle* handle, IsoTpMessage* message);
+    // Private
+    uint16_t arbitration_id;
+    IsoTpMessageReceivedHandler message_received_callback;
+    uint16_t timeout_ms;
+    // timeout_ms: ISO_TP_DEFAULT_RESPONSE_TIMEOUT,
+    bool frame_padding;
+    // frame_padding: ISO_TP_DEFAULT_FRAME_PADDING_STATUS,
+    uint8_t* receive_buffer;
+    uint16_t received_buffer_size;
+    uint16_t incoming_message_size;
+    // TODO timer callback for multi frame
+} IsoTpReceiveHandle;
 
+/* Public: Initiate receiving a single ISO-TP message on a particular
+ * arbitration ID.
+ *
+ * Note that no actual CAN data has been received at this point - this just sets
+ * up a handle to be used when new CAN messages to arrive, so they can be parsed
+ * as potential single or multi-frame ISO-TP messages.
+ *
+ * shims -  Low-level shims required to send and receive CAN messages, etc.
+ * arbitration_id - The arbitration ID to receive the message on.
+ * callback - an optional function to be called when the message is completely
+ *      received (use NULL if no callback required).
+ *
+ * Returns a handle to be used with isotp_continue_receive when a new CAN frame
+ * arrives. The 'completed' field in the returned IsoTpReceiveHandle will be true
+ * when the message is completely sent.
+ */
 IsoTpReceiveHandle isotp_receive(IsoTpShims* shims,
         const uint16_t arbitration_id, IsoTpMessageReceivedHandler callback);
 
+/* Public: Continue to receive a an ISO-TP message, based on a freshly
+ * received CAN message.
+ *
+ * For a multi-frame ISO-TP message, this function must be called
+ * repeatedly whenever a new CAN message is received in order to complete
+ * receipt.
+ *
+ * TODO does this API work for if we wanted to receive an ISO-TP message and
+ * send our own flow control messages back?
+ *
+ * shims -  Low-level shims required to send and receive CAN messages, etc.
+ * handle - An IsoTpReceiveHandle previously returned by isotp_receive(...).
+ * arbitration_id - The arbitration_id of the received CAN message.
+ * data - The data of the received CAN message.
+ * size - The size of the data in the received CAN message.
+ *
+ * Returns an IsoTpMessage with the 'completed' field set to true if a message
+ * was completely received. If 'completed' is false, more CAN frames are
+ * required to complete the messages, or the arbitration ID didn't match this
+ * handle. Keep passing the same handle to this function when CAN frames arrive.
+ */
 IsoTpMessage isotp_continue_receive(IsoTpShims* shims,
         IsoTpReceiveHandle* handle, const uint16_t arbitration_id,
         const uint8_t data[], const uint8_t size);