fsmonitor--daemon.h

   1 #ifndef FSMONITOR_DAEMON_H
   2 #define FSMONITOR_DAEMON_H
   3
   4 #ifdef HAVE_FSMONITOR_DAEMON_BACKEND
   5
   6 #include "cache.h"
   7 #include "dir.h"
   8 #include "run-command.h"
   9 #include "simple-ipc.h"
  10 #include "thread-utils.h"
  11
  12 struct fsmonitor_batch;
  13 struct fsmonitor_token_data;
  14
  15 /*
  16  * Create a new batch of path(s).  The returned batch is considered
  17  * private and not linked into the fsmonitor daemon state.  The caller
  18  * should fill this batch with one or more paths and then publish it.
  19  */
  20 struct fsmonitor_batch *fsmonitor_batch__new(void);
  21
  22 /*
  23  * Free the list of batches starting with this one.
  24  */
  25 void fsmonitor_batch__free_list(struct fsmonitor_batch *batch);
  26
  27 /*
  28  * Add this path to this batch of modified files.
  29  *
  30  * The batch should be private and NOT (yet) linked into the fsmonitor
  31  * daemon state and therefore not yet visible to worker threads and so
  32  * no locking is required.
  33  */
  34 void fsmonitor_batch__add_path(struct fsmonitor_batch *batch, const char *path);
  35
  36 struct fsmonitor_daemon_backend_data; /* opaque platform-specific data */
  37
  38 struct fsmonitor_daemon_state {
  39         pthread_t listener_thread;
  40         pthread_mutex_t main_lock;
  41
  42         struct strbuf path_worktree_watch;
  43         struct strbuf path_gitdir_watch;
  44         int nr_paths_watching;
  45
  46         struct fsmonitor_token_data *current_token_data;
  47
  48         struct strbuf path_cookie_prefix;
  49         pthread_cond_t cookies_cond;
  50         int cookie_seq;
  51         struct hashmap cookies;
  52
  53         int error_code;
  54         struct fsmonitor_daemon_backend_data *backend_data;
  55
  56         struct ipc_server_data *ipc_server_data;
  57 };
  58
  59 /*
  60  * Pathname classifications.
  61  *
  62  * The daemon classifies the pathnames that it receives from file
  63  * system notification events into the following categories and uses
  64  * that to decide whether clients are told about them.  (And to watch
  65  * for file system synchronization events.)
  66  *
  67  * The daemon only collects and reports on the set of modified paths
  68  * within the working directory (proper).
  69  *
  70  * The client should only care about paths within the working
  71  * directory proper (inside the working directory and not ".git" nor
  72  * inside of ".git/").  That is, the client has read the index and is
  73  * asking for a list of any paths in the working directory that have
  74  * been modified since the last token.  The client does not care about
  75  * file system changes within the ".git/" directory (such as new loose
  76  * objects or packfiles).  So the client will only receive paths that
  77  * are classified as IS_WORKDIR_PATH.
  78  *
  79  * Note that ".git" is usually a directory and is therefore inside
  80  * the cone of the FS watch that we have on the working directory root,
  81  * so we will also get FS events for disk activity on and within ".git/"
  82  * that we need to respond to or filter from the client.
  83  *
  84  * But Git also allows ".git" to be a *file* that points to a GITDIR
  85  * outside of the working directory.  When this happens, we need to
  86  * create FS watches on both the working directory root *and* on the
  87  * (external) GITDIR root.  (The latter is required because we put
  88  * cookie files inside it and use them to sync with the FS event
  89  * stream.)
  90  *
  91  * Note that in the context of this discussion, I'm using "GITDIR"
  92  * to only mean an external GITDIR referenced by a ".git" file.
  93  *
  94  * The platform FS event backends will receive watch-specific
  95  * relative paths (except for those OS's that always emit absolute
  96  * paths).  We use the following enum and routines to classify each
  97  * path so that we know how to handle it.  There is a slight asymmetry
  98  * here because ".git/" is inside the working directory and the
  99  * (external) GITDIR is not, and therefore how we handle events may
 100  * vary slightly, so I have different enums for "IS...DOT_GIT..." and
 101  * "IS...GITDIR...".
 102  *
 103  * The daemon uses the IS_DOT_GIT and IS_GITDIR internally to mean the
 104  * exact ".git" file/directory or GITDIR directory.  If the daemon
 105  * receives a delete event for either of these paths, it will
 106  * automatically shutdown, for example.
 107  *
 108  * Note that the daemon DOES NOT explicitly watch nor special case the
 109  * index.  The daemon does not read the index nor have any internal
 110  * index-relative state, so there are no "IS...INDEX..." enum values.
 111  */
 112 enum fsmonitor_path_type {
 113         IS_WORKDIR_PATH = 0,
 114
 115         IS_DOT_GIT,
 116         IS_INSIDE_DOT_GIT,
 117         IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX,
 118
 119         IS_GITDIR,
 120         IS_INSIDE_GITDIR,
 121         IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX,
 122
 123         IS_OUTSIDE_CONE,
 124 };
 125
 126 /*
 127  * Classify a pathname relative to the root of the working directory.
 128  */
 129 enum fsmonitor_path_type fsmonitor_classify_path_workdir_relative(
 130         const char *relative_path);
 131
 132 /*
 133  * Classify a pathname relative to a <gitdir> that is external to the
 134  * worktree directory.
 135  */
 136 enum fsmonitor_path_type fsmonitor_classify_path_gitdir_relative(
 137         const char *relative_path);
 138
 139 /*
 140  * Classify an absolute pathname received from a filesystem event.
 141  */
 142 enum fsmonitor_path_type fsmonitor_classify_path_absolute(
 143         struct fsmonitor_daemon_state *state,
 144         const char *path);
 145
 146 /*
 147  * Prepend the this batch of path(s) onto the list of batches associated
 148  * with the current token.  This makes the batch visible to worker threads.
 149  *
 150  * The caller no longer owns the batch and must not free it.
 151  *
 152  * Wake up the client threads waiting on these cookies.
 153  */
 154 void fsmonitor_publish(struct fsmonitor_daemon_state *state,
 155                        struct fsmonitor_batch *batch,
 156                        const struct string_list *cookie_names);
 157
 158 /*
 159  * If the platform-specific layer loses sync with the filesystem,
 160  * it should call this to invalidate cached data and abort waiting
 161  * threads.
 162  */
 163 void fsmonitor_force_resync(struct fsmonitor_daemon_state *state);
 164
 165 #endif /* HAVE_FSMONITOR_DAEMON_BACKEND */
 166 #endif /* FSMONITOR_DAEMON_H */