Message sequencing allows Marionette to provide an asynchronous,
parallel pipelining user-facing interface, limit chances of payload
race conditions, and remove stylistic inconsistencies in how commands
and responses are dispatched internally.
Clients that deliver a blocking WebDriver interface are still be expected
to not send further command requests before the response from the last
command has come back, but if they still happen to do so because of
programming error or otherwise, no harm will be done. This will guard
against bugs such as bug 1207125.
This patch formalises the command and response concepts, and applies
these concepts to emulator callbacks. Through the new message format,
Marionette is able to provide two-way parallel communication. In other
words, the server will be able to instruct the client to perform a
command in a non ad-hoc way.
runEmulatorCmd and runEmulatorShell are both turned into command
instructions originating from the server. This resolves a lot of
technical debt in the server code because they are no longer special-cased
to circumvent the dispatching technique used for all other commands;
commands may originate from either the client or the server providing
parallel pipelining enforced through message sequencing:
client server
| |
msgid=1 |----------->|
| command |
| |
msgid=2 |<-----------|
| command |
| |
msgid=2 |----------->|
| response |
| |
msgid=1 |<-----------|
| response |
| |
The protocol now consists of a "Command" message and the corresponding
"Response" message. A "Response" message must always be sent in reply
to a "Command" message.
This bumps the Marionette protocol level to 3.
r=dburns
r=jgriffin
--HG--
extra : commitid : 1kz4Oa2q3Un
Message sequencing allows Marionette to provide an asynchronous,
parallel pipelining user-facing interface, limit chances of payload
race conditions, and remove stylistic inconsistencies in how commands
and responses are dispatched internally.
Clients that deliver a blocking WebDriver interface are still be expected
to not send further command requests before the response from the last
command has come back, but if they still happen to do so because of
programming error or otherwise, no harm will be done. This will guard
against bugs such as bug 1207125.
This patch formalises the command and response concepts, and applies
these concepts to emulator callbacks. Through the new message format,
Marionette is able to provide two-way parallel communication. In other
words, the server will be able to instruct the client to perform a
command in a non ad-hoc way.
runEmulatorCmd and runEmulatorShell are both turned into command
instructions originating from the server. This resolves a lot of
technical debt in the server code because they are no longer special-cased
to circumvent the dispatching technique used for all other commands;
commands may originate from either the client or the server providing
parallel pipelining enforced through message sequencing:
client server
| |
msgid=1 |----------->|
| command |
| |
msgid=2 |<-----------|
| command |
| |
msgid=2 |----------->|
| response |
| |
msgid=1 |<-----------|
| response |
| |
The protocol now consists of a "Command" message and the corresponding
"Response" message. A "Response" message must always be sent in reply
to a "Command" message.
This bumps the Marionette protocol level to 3.
r=dburns
r=jgriffin
--HG--
extra : commitid : 2upWRuXyqPF
extra : rebase_source : f384801e209e4b49ef57055fd550c3c435ece4ef
Linting; no functional changes.
--HG--
extra : rebase_source : bf63a6d317af1cba44c6608437c0b0894e8231ce
extra : source : ec2b1317d3c6389826da0e8e8c12176ff2cf9eeb
Emulator callbacks are now created dynamically upon request, and uses
a nicer data structure in chrome context. Each emulator callback is
encapsulated in EmulatorCallback, and stored on Emulator.
Emulator is stored on Dispatcher (as opposed to in marionette-server.js)
which bypasses some of the problems with circumventing the Marionette
protocol in GeckoDriver because of CommandProcessor.
Emulator callbacks to the client should be considered transparent, hence
they do not use the ListenerProxy. They are explicitly meant _not_
to be blocking.
--HG--
extra : rebase_source : f9fa688f7ec2401dbe3b18713cef7a9c0a4ab0f5
extra : source : eeb3d39874b17e02888427afb9709f35abc95120
