lightning

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Commit Graph

Author	SHA1	Message	Date
Rusty Russell	240abf6c46	common/io_lock: add helper to query if lock is taken. Not just for debugging; we actually need to know if a write is active for the coming hack. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>	6 years ago
Christian Decker	bb38541d9e	common: Added a small locking mechanism to simplify how we lock IO We've done this a number of times already where we're getting exclusive access to either the out direction of a connection, or we try to lock out the read side while we are responding to a previous request. They usually are really cumbersome because we reach around to the other direction to stop it from proceeding, or we flag our exclusive access somewhere, and we always need to know whom to notify. PR ElementsProject/lightning#1970 adds two new instances of this: - Streaming a JSON response requires that nothing else should write while the stream is active. - We also want to stop reading new requests while we are responding to one. To remove the complexity of having to know whom to stop and notify when we're done, this adds a simple `io_lock` primitive that can be used to get exclusive access to a connection. This inverts the requirement for notifications, since everybody registers interest in the lock and they get notified if the lock holder releases it.	6 years ago

Author

SHA1

Message

Date

Rusty Russell

240abf6c46

common/io_lock: add helper to query if lock is taken.

Not just for debugging; we actually need to know if a write is active for
the coming hack.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

6 years ago

Christian Decker

bb38541d9e

common: Added a small locking mechanism to simplify how we lock IO

We've done this a number of times already where we're getting
exclusive access to either the out direction of a connection, or we
try to lock out the read side while we are responding to a previous
request. They usually are really cumbersome because we reach around to
the other direction to stop it from proceeding, or we flag our
exclusive access somewhere, and we always need to know whom to notify.

PR ElementsProject/lightning#1970 adds two new instances of this:

 - Streaming a JSON response requires that nothing else should write
   while the stream is active.
 - We also want to stop reading new requests while we are responding
   to one.

To remove the complexity of having to know whom to stop and notify
when we're done, this adds a simple `io_lock` primitive that can be
used to get exclusive access to a connection. This inverts the
requirement for notifications, since everybody registers interest in
the lock and they get notified if the lock holder releases it.

6 years ago

2 Commits (e11ddfc99282c865989da5883d4027f26d5671e2)