fsmonitor--daemon.h

   1 #ifndef FSMONITOR_DAEMON_H
   2 #define FSMONITOR_DAEMON_H
   3
   4 #ifdef HAVE_FSMONITOR_DAEMON_BACKEND
   5
   6 #include "hashmap.h"
   7 #include "thread-utils.h"
   8 #include "fsmonitor-path-utils.h"
   9
  10 struct fsmonitor_batch;
  11 struct fsmonitor_token_data;
  12
  13 /*
  14  * Create a new batch of path(s).  The returned batch is considered
  15  * private and not linked into the fsmonitor daemon state.  The caller
  16  * should fill this batch with one or more paths and then publish it.
  17  */
  18 struct fsmonitor_batch *fsmonitor_batch__new(void);
  19
  20 /*
  21  * Free the list of batches starting with this one.
  22  */
  23 void fsmonitor_batch__free_list(struct fsmonitor_batch *batch);
  24
  25 /*
  26  * Add this path to this batch of modified files.
  27  *
  28  * The batch should be private and NOT (yet) linked into the fsmonitor
  29  * daemon state and therefore not yet visible to worker threads and so
  30  * no locking is required.
  31  */
  32 void fsmonitor_batch__add_path(struct fsmonitor_batch *batch, const char *path);
  33
  34 struct fsm_listen_data; /* opaque platform-specific data for listener thread */
  35 struct fsm_health_data; /* opaque platform-specific data for health thread */
  36
  37 struct fsmonitor_daemon_state {
  38         pthread_t listener_thread;
  39         pthread_t health_thread;
  40         pthread_mutex_t main_lock;
  41
  42         struct strbuf path_worktree_watch;
  43         struct strbuf path_gitdir_watch;
  44         struct alias_info alias;
  45         int nr_paths_watching;
  46
  47         struct fsmonitor_token_data *current_token_data;
  48
  49         struct strbuf path_cookie_prefix;
  50         pthread_cond_t cookies_cond;
  51         int cookie_seq;
  52         struct hashmap cookies;
  53
  54         int listen_error_code;
  55         int health_error_code;
  56         struct fsm_listen_data *listen_data;
  57         struct fsm_health_data *health_data;
  58
  59         struct ipc_server_data *ipc_server_data;
  60         struct strbuf path_ipc;
  61
  62 };
  63
  64 /*
  65  * Pathname classifications.
  66  *
  67  * The daemon classifies the pathnames that it receives from file
  68  * system notification events into the following categories and uses
  69  * that to decide whether clients are told about them.  (And to watch
  70  * for file system synchronization events.)
  71  *
  72  * The daemon only collects and reports on the set of modified paths
  73  * within the working directory (proper).
  74  *
  75  * The client should only care about paths within the working
  76  * directory proper (inside the working directory and not ".git" nor
  77  * inside of ".git/").  That is, the client has read the index and is
  78  * asking for a list of any paths in the working directory that have
  79  * been modified since the last token.  The client does not care about
  80  * file system changes within the ".git/" directory (such as new loose
  81  * objects or packfiles).  So the client will only receive paths that
  82  * are classified as IS_WORKDIR_PATH.
  83  *
  84  * Note that ".git" is usually a directory and is therefore inside
  85  * the cone of the FS watch that we have on the working directory root,
  86  * so we will also get FS events for disk activity on and within ".git/"
  87  * that we need to respond to or filter from the client.
  88  *
  89  * But Git also allows ".git" to be a *file* that points to a GITDIR
  90  * outside of the working directory.  When this happens, we need to
  91  * create FS watches on both the working directory root *and* on the
  92  * (external) GITDIR root.  (The latter is required because we put
  93  * cookie files inside it and use them to sync with the FS event
  94  * stream.)
  95  *
  96  * Note that in the context of this discussion, I'm using "GITDIR"
  97  * to only mean an external GITDIR referenced by a ".git" file.
  98  *
  99  * The platform FS event backends will receive watch-specific
 100  * relative paths (except for those OSes that always emit absolute
 101  * paths).  We use the following enum and routines to classify each
 102  * path so that we know how to handle it.  There is a slight asymmetry
 103  * here because ".git/" is inside the working directory and the
 104  * (external) GITDIR is not, and therefore how we handle events may
 105  * vary slightly, so I have different enums for "IS...DOT_GIT..." and
 106  * "IS...GITDIR...".
 107  *
 108  * The daemon uses the IS_DOT_GIT and IS_GITDIR internally to mean the
 109  * exact ".git" file/directory or GITDIR directory.  If the daemon
 110  * receives a delete event for either of these paths, it will
 111  * automatically shutdown, for example.
 112  *
 113  * Note that the daemon DOES NOT explicitly watch nor special case the
 114  * index.  The daemon does not read the index nor have any internal
 115  * index-relative state, so there are no "IS...INDEX..." enum values.
 116  */
 117 enum fsmonitor_path_type {
 118         IS_WORKDIR_PATH = 0,
 119
 120         IS_DOT_GIT,
 121         IS_INSIDE_DOT_GIT,
 122         IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX,
 123
 124         IS_GITDIR,
 125         IS_INSIDE_GITDIR,
 126         IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX,
 127
 128         IS_OUTSIDE_CONE,
 129 };
 130
 131 /*
 132  * Classify a pathname relative to the root of the working directory.
 133  */
 134 enum fsmonitor_path_type fsmonitor_classify_path_workdir_relative(
 135         const char *relative_path);
 136
 137 /*
 138  * Classify a pathname relative to a <gitdir> that is external to the
 139  * worktree directory.
 140  */
 141 enum fsmonitor_path_type fsmonitor_classify_path_gitdir_relative(
 142         const char *relative_path);
 143
 144 /*
 145  * Classify an absolute pathname received from a filesystem event.
 146  */
 147 enum fsmonitor_path_type fsmonitor_classify_path_absolute(
 148         struct fsmonitor_daemon_state *state,
 149         const char *path);
 150
 151 /*
 152  * Prepend the this batch of path(s) onto the list of batches associated
 153  * with the current token.  This makes the batch visible to worker threads.
 154  *
 155  * The caller no longer owns the batch and must not free it.
 156  *
 157  * Wake up the client threads waiting on these cookies.
 158  */
 159 void fsmonitor_publish(struct fsmonitor_daemon_state *state,
 160                        struct fsmonitor_batch *batch,
 161                        const struct string_list *cookie_names);
 162
 163 /*
 164  * If the platform-specific layer loses sync with the filesystem,
 165  * it should call this to invalidate cached data and abort waiting
 166  * threads.
 167  */
 168 void fsmonitor_force_resync(struct fsmonitor_daemon_state *state);
 169
 170 #endif /* HAVE_FSMONITOR_DAEMON_BACKEND */
 171 #endif /* FSMONITOR_DAEMON_H */