Precise command constants on adb/protoxol.txt
Try to improve the documentation by adding, for each commands explained
on the adb/protocol.txt file (CONNECT, WRITE, AUTH, ...), the
corresponding constant used by the protocol (A_CNXN, A_WRTE,
A_AUTH, ...).
I've seen a few engineers having problems matching these both
information by simply reading the doc and they loose time before
getting it. Most of the time they understand it by finally reading the
source code.
By adding this simple information at the end of each command
description I'm sure it will help onboarding developers to
understand more quickly the way the ADB protocol works.
Change-Id: Ibb949fd6a6d34a2bc7f47f0e7af2f57138c9a369
Signed-off-by: Eyal Lezmy <eyal.lezmy@gmail.com>
diff --git a/adb/protocol.txt b/adb/protocol.txt
index 5c7c6ba..55ea87f 100644
--- a/adb/protocol.txt
+++ b/adb/protocol.txt
@@ -29,12 +29,12 @@
32 bit words which are sent across the wire in little endian format.
struct message {
- unsigned command; /* command identifier constant */
- unsigned arg0; /* first argument */
- unsigned arg1; /* second argument */
- unsigned data_length; /* length of payload (0 is allowed) */
- unsigned data_crc32; /* crc32 of data payload */
- unsigned magic; /* command ^ 0xffffffff */
+ unsigned command; /* command identifier constant (A_CNXN, ...) */
+ unsigned arg0; /* first argument */
+ unsigned arg1; /* second argument */
+ unsigned data_length; /* length of payload (0 is allowed) */
+ unsigned data_crc32; /* crc32 of data payload */
+ unsigned magic; /* command ^ 0xffffffff */
};
Receipt of an invalid message header, corrupt message payload, or an
@@ -55,6 +55,8 @@
--- CONNECT(version, maxdata, "system-identity-string") ----------------
+Command constant: A_CNXN
+
The CONNECT message establishes the presence of a remote system.
The version is used to ensure protocol compatibility and maxdata
declares the maximum message body size that the remote system
@@ -80,6 +82,8 @@
--- AUTH(type, 0, "data") ----------------------------------------------
+Command constant: A_AUTH
+
The AUTH message informs the recipient that authentication is required to
connect to the sender. If type is TOKEN(1), data is a random token that
the recipient can sign with a private key. The recipient replies with an
@@ -98,6 +102,8 @@
--- OPEN(local-id, 0, "destination") -----------------------------------
+Command constant: A_OPEN
+
The OPEN message informs the recipient that the sender has a stream
identified by local-id that it wishes to connect to the named
destination in the message payload. The local-id may not be zero.
@@ -120,11 +126,13 @@
--- READY(local-id, remote-id, "") -------------------------------------
+Command constant: A_OKAY
+
The READY message informs the recipient that the sender's stream
identified by local-id is ready for write messages and that it is
connected to the recipient's stream identified by remote-id.
-Neither the local-id nor the remote-id may be zero.
+Neither the local-id nor the remote-id may be zero.
A READY message containing a remote-id which does not map to an open
stream on the recipient's side is ignored. The stream may have been
@@ -135,9 +143,10 @@
not change on later READY messages sent to the same stream.
-
--- WRITE(local-id, remote-id, "data") ---------------------------------
+Command constant: A_WRTE
+
The WRITE message sends data to the recipient's stream identified by
remote-id. The payload MUST be <= maxdata in length.
@@ -154,6 +163,8 @@
--- CLOSE(local-id, remote-id, "") -------------------------------------
+Command constant: A_CLSE
+
The CLOSE message informs recipient that the connection between the
sender's stream (local-id) and the recipient's stream (remote-id) is
broken. The remote-id MUST not be zero, but the local-id MAY be zero
@@ -170,12 +181,14 @@
--- SYNC(online, sequence, "") -----------------------------------------
+Command constant: A_SYNC
+
The SYNC message is used by the io pump to make sure that stale
outbound messages are discarded when the connection to the remote side
is broken. It is only used internally to the bridge and never valid
-to send across the wire.
+to send across the wire.
-* when the connection to the remote side goes offline, the io pump
+* when the connection to the remote side goes offline, the io pump
sends a SYNC(0, 0) and starts discarding all messages
* when the connection to the remote side is established, the io pump
sends a SYNC(1, token) and continues to discard messages