summaryrefslogtreecommitdiff
path: root/builtin/fsmonitor--daemon.c
AgeCommit message (Collapse)AuthorFilesLines
2022-03-25fsmonitor--daemon: use a cookie file to sync with file systemLibravatar Jeff Hostetler1-1/+236
Teach fsmonitor--daemon client threads to create a cookie file inside the .git directory and then wait until FS events for the cookie are observed by the FS listener thread. This helps address the racy nature of file system events by blocking the client response until the kernel has drained any event backlog. This is especially important on MacOS where kernel events are only issued with a limited frequency. See the `latency` argument of `FSeventStreamCreate()`. The kernel only signals every `latency` seconds, but does not guarantee that the kernel queue is completely drained, so we may have to wait more than one interval. If we increase the latency, the system is more likely to drop events. We avoid these issues by having each client thread create a unique cookie file and then wait until it is seen in the event stream. Co-authored-by: Kevin Willford <Kevin.Willford@microsoft.com> Co-authored-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: periodically truncate list of modified filesLibravatar Jeff Hostetler1-0/+88
Teach fsmonitor--daemon to periodically truncate the list of modified files to save some memory. Clients will ask for the set of changes relative to a token that they found in the FSMN index extension in the index. (This token is like a point in time, but different). Clients will then update the index to contain the response token (so that subsequent commands will be relative to this new token). Therefore, the daemon can gradually truncate the in-memory list of changed paths as they become obsolete (older than the previous token). Since we may have multiple clients making concurrent requests with a skew of tokens and clients may be racing to the talk to the daemon, we lazily truncate the list. We introduce a 5 minute delay and truncate batches 5 minutes after they are considered obsolete. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: implement handle_client callbackLibravatar Jeff Hostetler1-2/+309
Teach fsmonitor--daemon to respond to IPC requests from client Git processes and respond with a list of modified pathnames relative to the provided token. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: create token-based changed path cacheLibravatar Jeff Hostetler1-2/+228
Teach fsmonitor--daemon to build a list of changed paths and associate them with a token-id. This will be used by the platform-specific backends to accumulate changed paths in response to filesystem events. The platform-specific file system listener thread receives file system events containing one or more changed pathnames (with whatever bucketing or grouping that is convenient for the file system). These paths are accumulated (without locking) by the file system layer into a `fsmonitor_batch`. When the file system layer has drained the kernel event queue, it will "publish" them to our token queue and make them visible to concurrent client worker threads. The token layer is free to combine and/or de-dup paths within these batches for efficient presentation to clients. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: define token-idsLibravatar Jeff Hostetler1-1/+115
Teach fsmonitor--daemon to create token-ids and define the overall token naming scheme. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: add pathname classificationLibravatar Jeff Hostetler1-0/+81
Teach fsmonitor--daemon to classify relative and absolute pathnames and decide how they should be handled. This will be used by the platform-specific backend to respond to each filesystem event. When we register for filesystem notifications on a directory, we get events for everything (recursively) in the directory. We want to report to clients changes to tracked and untracked paths within the working directory proper. We do not want to report changes within the .git directory, for example. This classification will be used in a later commit by the different backends to classify paths as events are received. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: implement 'start' commandLibravatar Jeff Hostetler1-2/+107
Implement 'git fsmonitor--daemon start' command. This command starts an instance of 'git fsmonitor--daemon run' in the background using the new 'start_bg_command()' function. We avoid the fork-and-call technique on Unix systems in favor of a fork-and-exec technique. This gives us more uniform Trace2 child-* events. It also makes our usage more consistent with Windows usage. On Windows, teach 'git fsmonitor--daemon run' to optionally call 'FreeConsole()' to release handles to the inherited Win32 console (despite being passed invalid handles for stdin/out/err). Without this, command prompts and powershell terminal windows could hang in "exit" until the last background child process exited or released their Win32 console handle. (This was not seen with git-bash shells because they don't have a Win32 console attached to them.) Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: implement 'run' commandLibravatar Jeff Hostetler1-1/+227
Implement `run` command to try to begin listening for file system events. This version defines the thread structure with a single fsmonitor_fs_listen thread to watch for file system events and a simple IPC thread pool to watch for connection from Git clients over a well-known named pipe or Unix domain socket. This commit does not actually do anything yet because the platform backends are still just stubs. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: implement 'stop' and 'status' commandsLibravatar Jeff Hostetler1-0/+51
Implement `stop` and `status` client commands to control and query the status of a `fsmonitor--daemon` server process (and implicitly start a server process if necessary). Later commits will implement the actual server and monitor the file system. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-25fsmonitor--daemon: add a built-in fsmonitor daemonLibravatar Jeff Hostetler1-0/+46
Create a built-in file system monitoring daemon that can be used by the existing `fsmonitor` feature (protocol API and index extension) to improve the performance of various Git commands, such as `status`. The `fsmonitor--daemon` feature builds upon the `Simple IPC` API and provides an alternative to hook access to existing fsmonitors such as `watchman`. This commit merely adds the new command without any functionality. Co-authored-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>