Package ch.bailu.gtk.glib

Class MainContext

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.type.Record
ch.bailu.gtk.glib.MainContext
All Implemented Interfaces:
PointerInterface
public class MainContext extends Record
The `GMainContext` struct is an opaque data
type representing a set of sources to be handled in a main loop.

https://docs.gtk.org/glib/struct.MainContext.html

  • Constructor Details

    • MainContext

      public MainContext(PointerContainer pointer)

    • MainContext

      public MainContext()
      Creates a new #GMainContext structure.

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • newWithFlagsMainContext

      public static MainContext newWithFlagsMainContext(int flags)
      Creates a new #GMainContext structure.
      Parameters:
      flags - a bitwise-OR combination of #GMainContextFlags flags that can only be set at creation time.
      Returns:
      the new #GMainContext

    • acquire

      public boolean acquire()
      Tries to become the owner of the specified context.
      If some other thread is the owner of the context,
      returns %FALSE immediately. Ownership is properly
      recursive: the owner can require ownership again
      and will release ownership when g_main_context_release()
      is called as many times as g_main_context_acquire().

      You must be the owner of a context before you
      can call g_main_context_prepare(), g_main_context_query(),
      g_main_context_check(), g_main_context_dispatch().
      Returns:
      %TRUE if the operation succeeded, and this thread is now the owner of @context.

    • addPoll

      public void addPoll(@Nonnull PollFD fd, int priority)
      Adds a file descriptor to the set of file descriptors polled for
      this context. This will very seldom be used directly. Instead
      a typical event source will use g_source_add_unix_fd() instead.
      Parameters:
      fd - a #GPollFD structure holding information about a file descriptor to watch.
      priority - the priority for this file descriptor which should be the same as the priority used for g_source_attach() to ensure that the file descriptor is polled whenever the results may be needed.

    • dispatch

      public void dispatch()
      Dispatches all pending sources.

      You must have successfully acquired the context with
      g_main_context_acquire() before you may call this function.

    • findSourceByFuncsUserData

      public Source findSourceByFuncsUserData(@Nonnull SourceFuncs funcs, @Nullable Pointer user_data)
      Finds a source with the given source functions and user data. If
      multiple sources exist with the same source function and user data,
      the first one found will be returned.
      Parameters:
      funcs - the @source_funcs passed to g_source_new().
      user_data - the user data from the callback.
      Returns:
      the source, if one was found, otherwise %NULL

    • findSourceById

      public Source findSourceById(int source_id)
      Finds a #GSource given a pair of context and ID.

      It is a programmer error to attempt to look up a non-existent source.

      More specifically: source IDs can be reissued after a source has been
      destroyed and therefore it is never valid to use this function with a
      source ID which may have already been removed. An example is when
      scheduling an idle to run in another thread with g_idle_add(): the
      idle may already have run and been removed by the time this function
      is called on its (now invalid) source ID. This source ID may have
      been reissued, leading to the operation being performed against the
      wrong source.
      Parameters:
      source_id - the source ID, as returned by g_source_get_id().
      Returns:
      the #GSource

    • findSourceByUserData

      public Source findSourceByUserData(@Nullable Pointer user_data)
      Finds a source with the given user data for the callback. If
      multiple sources exist with the same user data, the first
      one found will be returned.
      Parameters:
      user_data - the user_data for the callback.
      Returns:
      the source, if one was found, otherwise %NULL

    • invoke

      public void invoke(MainContext.OnSourceFunc function, @Nullable Pointer data)
      Invokes a function in such a way that @context is owned during the
      invocation of @function.

      If @context is %NULL then the global default main context — as
      returned by g_main_context_default() — is used.

      If @context is owned by the current thread, @function is called
      directly. Otherwise, if @context is the thread-default main context
      of the current thread and g_main_context_acquire() succeeds, then
      @function is called and g_main_context_release() is called
      afterwards.

      In any other case, an idle source is created to call @function and
      that source is attached to @context (presumably to be run in another
      thread). The idle source is attached with %G_PRIORITY_DEFAULT
      priority. If you want a different priority, use
      g_main_context_invoke_full().

      Note that, as with normal idle functions, @function should probably
      return %FALSE. If it returns %TRUE, it will be continuously run in a
      loop (and may prevent this call from returning).
      Parameters:
      function - function to call
      data - data to pass to @function

    • invokeFull

      public void invokeFull(int priority, MainContext.OnSourceFunc function, @Nullable Pointer data, MainContext.OnDestroyNotify notify)
      Invokes a function in such a way that @context is owned during the
      invocation of @function.

      This function is the same as g_main_context_invoke() except that it
      lets you specify the priority in case @function ends up being
      scheduled as an idle and also lets you give a #GDestroyNotify for @data.

      @notify should not assume that it is called from any particular
      thread or with any particular context acquired.
      Parameters:
      priority - the priority at which to run @function
      function - function to call
      data - data to pass to @function
      notify - a function to call when @data is no longer in use, or %NULL.

    • isOwner

      public boolean isOwner()
      Determines whether this thread holds the (recursive)
      ownership of this #GMainContext. This is useful to
      know before waiting on another thread that may be
      blocking to get ownership of @context.
      Returns:
      %TRUE if current thread is owner of @context.

    • iteration

      public boolean iteration(boolean may_block)
      Runs a single iteration for the given main loop. This involves
      checking to see if any event sources are ready to be processed,
      then if no events sources are ready and @may_block is %TRUE, waiting
      for a source to become ready, then dispatching the highest priority
      events sources that are ready. Otherwise, if @may_block is %FALSE
      sources are not waited to become ready, only those highest priority
      events sources will be dispatched (if any), that are ready at this
      given moment without further waiting.

      Note that even when @may_block is %TRUE, it is still possible for
      g_main_context_iteration() to return %FALSE, since the wait may
      be interrupted for other reasons than an event source becoming ready.
      Parameters:
      may_block - whether the call may block.
      Returns:
      %TRUE if events were dispatched.

    • pending

      public boolean pending()
      Checks if any sources have pending events for the given context.
      Returns:
      %TRUE if events are pending.

    • popThreadDefault

      public void popThreadDefault()
      Pops @context off the thread-default context stack (verifying that
      it was on the top of the stack).

    • prepare

      public boolean prepare(@Nullable Int priority)
      Prepares to poll sources within a main loop. The resulting information
      for polling is determined by calling g_main_context_query ().

      You must have successfully acquired the context with
      g_main_context_acquire() before you may call this function.
      Parameters:
      priority - location to store priority of highest priority source already ready.
      Returns:
      %TRUE if some source is ready to be dispatched prior to polling.

    • pushThreadDefault

      public void pushThreadDefault()
      Acquires @context and sets it as the thread-default context for the
      current thread. This will cause certain asynchronous operations
      (such as most [gio][gio]-based I/O) which are
      started in this thread to run under @context and deliver their
      results to its main loop, rather than running under the global
      default context in the main thread. Note that calling this function
      changes the context returned by g_main_context_get_thread_default(),
      not the one returned by g_main_context_default(), so it does not affect
      the context used by functions like g_idle_add().

      Normally you would call this function shortly after creating a new
      thread, passing it a #GMainContext which will be run by a
      #GMainLoop in that thread, to set a new default context for all
      async operations in that thread. In this case you may not need to
      ever call g_main_context_pop_thread_default(), assuming you want the
      new #GMainContext to be the default for the whole lifecycle of the
      thread.

      If you don't have control over how the new thread was created (e.g.
      in the new thread isn't newly created, or if the thread life
      cycle is managed by a #GThreadPool), it is always suggested to wrap
      the logic that needs to use the new #GMainContext inside a
      g_main_context_push_thread_default() / g_main_context_pop_thread_default()
      pair, otherwise threads that are re-used will end up never explicitly
      releasing the #GMainContext reference they hold.

      In some cases you may want to schedule a single operation in a
      non-default context, or temporarily use a non-default context in
      the main thread. In that case, you can wrap the call to the
      asynchronous operation inside a
      g_main_context_push_thread_default() /
      g_main_context_pop_thread_default() pair, but it is up to you to
      ensure that no other asynchronous operations accidentally get
      started while the non-default context is active.

      Beware that libraries that predate this function may not correctly
      handle being used from a thread with a thread-default context. Eg,
      see g_file_supports_thread_contexts().

    • ref

      public MainContext ref()
      Increases the reference count on a #GMainContext object by one.
      Returns:
      the @context that was passed in (since 2.6)

    • release

      public void release()
      Releases ownership of a context previously acquired by this thread
      with g_main_context_acquire(). If the context was acquired multiple
      times, the ownership will be released only when g_main_context_release()
      is called as many times as it was acquired.

    • removePoll

      public void removePoll(@Nonnull PollFD fd)
      Removes file descriptor from the set of file descriptors to be
      polled for a particular context.
      Parameters:
      fd - a #GPollFD descriptor previously added with g_main_context_add_poll()

    • setPollFunc

      public void setPollFunc(MainContext.OnPollFunc func)
      Sets the function to use to handle polling of file descriptors. It
      will be used instead of the poll() system call
      (or GLib's replacement function, which is used where
      poll() isn't available).

      This function could possibly be used to integrate the GLib event
      loop with an external event loop.
      Parameters:
      func - the function to call to poll all file descriptors

    • unref

      public void unref()
      Decreases the reference count on a #GMainContext object by one. If
      the result is zero, free the context and free all associated memory.

    • wakeup

      public void wakeup()
      If @context is currently blocking in g_main_context_iteration()
      waiting for a source to become ready, cause it to stop blocking
      and return. Otherwise, cause the next invocation of
      g_main_context_iteration() to return without blocking.

      This API is useful for low-level control over #GMainContext; for
      example, integrating it with main loop implementations such as
      #GMainLoop.

      Another related use for this function is when implementing a main
      loop with a termination condition, computed from multiple threads: 
      <!-- language="C" -->
   #define NUM_TASKS 10
   static gint tasks_remaining = NUM_TASKS;  // (atomic)
   ...
  
   while (g_atomic_int_get (&tasks_remaining) != 0)
     g_main_context_iteration (NULL, TRUE);


      Then in a thread: 
      <!-- language="C" -->
   perform_work();
 
   if (g_atomic_int_dec_and_test (&tasks_remaining))
     g_main_context_wakeup (NULL);

    • _default

      public static MainContext _default()
      Returns the global default main context. This is the main context
      used for main loop functions when a main loop is not explicitly
      specified, and corresponds to the "main" main loop. See also
      g_main_context_get_thread_default().
      Returns:
      the global default main context.

    • getThreadDefault

      public static MainContext getThreadDefault()
      Gets the thread-default #GMainContext for this thread. Asynchronous
      operations that want to be able to be run in contexts other than
      the default one should call this method or
      g_main_context_ref_thread_default() to get a #GMainContext to add
      their #GSources to. (Note that even in single-threaded
      programs applications may sometimes want to temporarily push a
      non-default context, so it is not safe to assume that this will
      always return %NULL if you are running in the default thread.)

      If you need to hold a reference on the context, use
      g_main_context_ref_thread_default() instead.
      Returns:
      the thread-default #GMainContext, or %NULL if the thread-default context is the global default context.

    • refThreadDefault

      public static MainContext refThreadDefault()
      Gets the thread-default #GMainContext for this thread, as with
      g_main_context_get_thread_default(), but also adds a reference to
      it with g_main_context_ref(). In addition, unlike
      g_main_context_get_thread_default(), if the thread-default context
      is the global default context, this will return that #GMainContext
      (with a ref added to it) rather than returning %NULL.
      Returns:
      the thread-default #GMainContext. Unref with g_main_context_unref() when you are done with it.

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()