Class Source

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.glib.Source
All Implemented Interfaces:
Proxy
@Generated("org.javagi.JavaGI") public class Source extends ProxyInstance
The GSource struct is an opaque data type representing an event source.

  • Constructor Details

    • Source

      public Source(MemorySegment address)
      Create a Source proxy instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • Source

      public Source(SourceFuncs sourceFuncs, int structSize)

      Creates a new GLib.Source structure.

      The size is specified to allow creating structures derived from GLib.Source that contain additional data. The size passed in must be at least sizeof (GSource).

      The source will not initially be associated with any GLib.MainContext and must be added to one with attach(MainContext) before it will be executed.

      Parameters:
      sourceFuncs - structure containing functions that implement the source‘s behavior
      structSize - size of the GLib.Source structure to create, in bytes

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the Source class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • readCallbackData

      public MemorySegment readCallbackData()
      Read the value of the field callback_data.
      Returns:
      The value of the field callback_data

    • writeCallbackData

      public void writeCallbackData(MemorySegment callbackData)
      Write a value in the field callback_data.
      Parameters:
      callbackData - The new value for the field callback_data

    • readCallbackFuncs

      public SourceCallbackFuncs readCallbackFuncs()
      Read the value of the field callback_funcs.
      Returns:
      The value of the field callback_funcs

    • writeCallbackFuncs

      public void writeCallbackFuncs(SourceCallbackFuncs callbackFuncs)
      Write a value in the field callback_funcs.
      Parameters:
      callbackFuncs - The new value for the field callback_funcs

    • readSourceFuncs

      public SourceFuncs readSourceFuncs()
      Read the value of the field source_funcs.
      Returns:
      The value of the field source_funcs

    • writeSourceFuncs

      public void writeSourceFuncs(SourceFuncs sourceFuncs)
      Write a value in the field source_funcs.
      Parameters:
      sourceFuncs - The new value for the field source_funcs

    • readRefCount

      public int readRefCount()
      Read the value of the field ref_count.
      Returns:
      The value of the field ref_count

    • writeRefCount

      public void writeRefCount(int refCount)
      Write a value in the field ref_count.
      Parameters:
      refCount - The new value for the field ref_count

    • readContext

      public MainContext readContext()
      Read the value of the field context.
      Returns:
      The value of the field context

    • writeContext

      public void writeContext(MainContext context)
      Write a value in the field context.
      Parameters:
      context - The new value for the field context

    • readPriority

      public int readPriority()
      Read the value of the field priority.
      Returns:
      The value of the field priority

    • writePriority

      public void writePriority(int priority)
      Write a value in the field priority.
      Parameters:
      priority - The new value for the field priority

    • readFlags

      public int readFlags()
      Read the value of the field flags.
      Returns:
      The value of the field flags

    • writeFlags

      public void writeFlags(int flags)
      Write a value in the field flags.
      Parameters:
      flags - The new value for the field flags

    • readSourceId

      public int readSourceId()
      Read the value of the field source_id.
      Returns:
      The value of the field source_id

    • writeSourceId

      public void writeSourceId(int sourceId)
      Write a value in the field source_id.
      Parameters:
      sourceId - The new value for the field source_id

    • readPollFds

      public SList<MemorySegment> readPollFds()
      Read the value of the field poll_fds.
      Returns:
      The value of the field poll_fds

    • writePollFds

      public void writePollFds(SList<MemorySegment> pollFds)
      Write a value in the field poll_fds.
      Parameters:
      pollFds - The new value for the field poll_fds

    • readPrev

      public Source readPrev()
      Read the value of the field prev.
      Returns:
      The value of the field prev

    • writePrev

      public void writePrev(Source prev)
      Write a value in the field prev.
      Parameters:
      prev - The new value for the field prev

    • readNext

      public Source readNext()
      Read the value of the field next.
      Returns:
      The value of the field next

    • writeNext

      public void writeNext(Source next)
      Write a value in the field next.
      Parameters:
      next - The new value for the field next

    • readName

      public String readName()
      Read the value of the field name.
      Returns:
      The value of the field name

    • writeName

      public void writeName(String name, Arena _arena)
      Write a value in the field name.
      Parameters:
      name - The new value for the field name
      _arena - to control the memory allocation scope

    • remove

      public static boolean remove(int tag)

      Removes the source with the given ID from the default main context.

      You must use destroy() for sources added to a non-default main context.

      The ID of a GLib.Source is given by getId(), or will be returned by the functions attach(MainContext), GLib.idleAdd(int, SourceFunc), GLib.idleAddFull, GLib.timeoutAdd(int, int, SourceFunc), GLib.timeoutAddFull, GLib.childWatchAdd(int, Pid, ChildWatchFunc), GLib.childWatchAddFull, GLib.ioAddWatch(IOChannel, int, Set, IOFunc), and GLib.ioAddWatchFull.

      It is a programmer error to attempt to remove 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 GLib.idleAdd(int, SourceFunc): 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:
      tag - the ID of the source to remove.
      Returns:
      true if the source was found and removed, false otherwise

    • removeByFuncsUserData

      public static boolean removeByFuncsUserData(SourceFuncs funcs, @Nullable MemorySegment userData)

      Removes a source from the default main loop context given the source functions and user data.

      If multiple sources exist with the same source functions and user data, only one will be destroyed.

      Parameters:
      funcs - the sourceFuncs passed to Source(SourceFuncs, int)
      userData - the user data for the callback
      Returns:
      true if a source was found and removed, false otherwise

    • removeByUserData

      public static boolean removeByUserData(@Nullable MemorySegment userData)

      Removes a source from the default main loop context given the user data for the callback.

      If multiple sources exist with the same user data, only one will be destroyed.

      Parameters:
      userData - the user_data for the callback
      Returns:
      true if a source was found and removed, false otherwise

    • setNameById

      public static void setNameById(int tag, String name)

      Sets the name of a source using its ID.

      This is a convenience utility to set source names from the return value of GLib.idleAdd(int, SourceFunc), GLib.timeoutAdd(int, int, SourceFunc), etc.

      It is a programmer error to attempt to set the name of 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 GLib.idleAdd(int, SourceFunc): 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:
      tag - a source ID
      name - debug name for the source
      Since:
      2.26

    • addChildSource

      public void addChildSource(Source childSource)

      Adds childSource to this Source as a ‘polled’ source.

      When this Source is added to a GLib.MainContext, childSource will be automatically added with the same priority. When childSource is triggered, it will cause this Source to dispatch (in addition to calling its own callback), and when this Source is destroyed, it will destroy childSource as well.

      The this Source will also still be dispatched if its own prepare/check functions indicate that it is ready.

      If you don’t need childSource to do anything on its own when it triggers, you can call g_source_set_dummy_callback() on it to set a callback that does nothing (except return true if appropriate).

      The this Source will hold a reference on childSource while childSource is attached to it.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      Parameters:
      childSource - a second source that this Source should ‘poll’
      Since:
      2.28

    • addPoll

      public void addPoll(PollFD fd)

      Adds a file descriptor to the set of file descriptors polled for this source.

      This is usually combined with Source(SourceFuncs, int) to add an event source. The event source’s check function will typically test the revents field in the GLib.PollFD struct and return true if events need to be processed.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      Using this API forces the linear scanning of event sources on each main loop iteration. Newly-written event sources should try to use g_source_add_unix_fd() instead of this API.

      Parameters:
      fd - a GLib.PollFD structure holding information about a file descriptor to watch

    • addUnixFd

      public MemorySegment addUnixFd(int fd, Set<IOCondition> events)

      Monitors fd for the IO events in events.

      The tag returned by this function can be used to remove or modify the monitoring of the fd using removeUnixFd(MemorySegment) or modifyUnixFd(MemorySegment, Set).

      It is not necessary to remove the file descriptor before destroying the source; it will be cleaned up automatically.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      fd - the file descriptor to monitor
      events - an event mask
      Returns:
      an opaque tag
      Since:
      2.36

    • addUnixFd

      public MemorySegment addUnixFd(int fd, IOCondition... events)

      Monitors fd for the IO events in events.

      The tag returned by this function can be used to remove or modify the monitoring of the fd using removeUnixFd(MemorySegment) or modifyUnixFd(MemorySegment, Set).

      It is not necessary to remove the file descriptor before destroying the source; it will be cleaned up automatically.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      fd - the file descriptor to monitor
      events - an event mask
      Returns:
      an opaque tag
      Since:
      2.36

    • attach

      public int attach(@Nullable MainContext context)

      Adds a GLib.Source to a context so that it will be executed within that context.

      Remove it by calling destroy().

      This function is safe to call from any thread, regardless of which thread the context is running in.

      Parameters:
      context - a main context (if NULL, the global-default main context will be used)
      Returns:
      the ID (greater than 0) for the source within the GLib.MainContext

    • destroy

      public void destroy()

      Removes a source from its GLib.MainContext, if any, and marks it as destroyed.

      The source cannot be subsequently added to another context. It is safe to call this on sources which have already been removed from their context.

      This does not unref the GLib.Source: if you still hold a reference, use unref() to drop it.

      This function is safe to call from any thread, regardless of which thread the GLib.MainContext is running in.

      If the source is currently attached to a GLib.MainContext, destroying it will effectively unset the callback similar to calling setCallback(SourceFunc). This can mean, that the data’s GLib.DestroyNotify gets called right away.

    • dupContext

      public @Nullable MainContext dupContext()

      Gets a reference to the GLib.MainContext with which the source is associated.

      You can call this on a source that has been destroyed. You can always call this function on the source returned from GLib.mainCurrentSource().

      Returns:
      the GLib.MainContext with which the source is associated, or NULL if the context has not yet been added to a source
      Since:
      2.86

    • getCanRecurse

      public boolean getCanRecurse()

      Checks whether a source is allowed to be called recursively.

      See setCanRecurse(boolean).

      Returns:
      whether recursion is allowed

    • getContext

      public @Nullable MainContext getContext()

      Gets the GLib.MainContext with which the source is associated.

      You can call this on a source that has been destroyed, provided that the GLib.MainContext it was attached to still exists (in which case it will return that GLib.MainContext). In particular, you can always call this function on the source returned from GLib.mainCurrentSource(). But calling this function on a source whose GLib.MainContext has been destroyed is an error.

      If the associated GLib.MainContext could be destroy concurrently from a different thread, then this function is not safe to call and dupContext() should be used instead.

      Returns:
      the main context with which the source is associated, or NULL if the context has not yet been added to a source

    • getCurrentTime

      @Deprecated public void getCurrentTime(TimeVal timeval)
      Deprecated.
      use getTime() instead
      This function ignores this Source and is otherwise the same as GLib.getCurrentTime(TimeVal).
      Parameters:
      timeval - GLib.TimeVal structure in which to store current time

    • getId

      public int getId()

      Returns the numeric ID for a particular source.

      The ID of a source is a positive integer which is unique within a particular main loop context. The reverse mapping from ID to source is done by MainContext.findSourceById(int).

      You can only call this function while the source is associated to a GLib.MainContext instance; calling this function before attach(MainContext) or after destroy() yields undefined behavior. The ID returned is unique within the GLib.MainContext instance passed to attach(MainContext).

      Returns:
      the ID (greater than 0) for the source

    • getName

      public @Nullable String getName()

      Gets a name for the source, used in debugging and profiling.

      The name may be NULL if it has never been set with setName(String).

      Returns:
      the name of the source
      Since:
      2.26

    • getPriority

      public int getPriority()
      Gets the priority of a source.
      Returns:
      the priority of the source

    • getReadyTime

      public long getReadyTime()

      Gets the ‘ready time’ of source, as set by setReadyTime(long).

      Any time before or equal to the current monotonic time (including zero) is an indication that the source will fire immediately.

      Returns:
      the monotonic ready time, -1 for ‘never’

    • getTime

      public long getTime()

      Gets the time to be used when checking this source.

      The advantage of calling this function over calling GLib.getMonotonicTime() directly is that when checking multiple sources, GLib can cache a single value instead of having to repeatedly get the system monotonic time.

      The time here is the system monotonic time, if available, or some other reasonable alternative otherwise. See GLib.getMonotonicTime().

      Returns:
      the monotonic time in microseconds
      Since:
      2.28

    • isDestroyed

      public boolean isDestroyed()

      Returns whether this Source has been destroyed.

      This is important when you operate upon your objects from within idle handlers, but may have freed the object before the dispatch of your idle handler.

      static gboolean
idle_callback (gpointer data)
{
  SomeWidget *self = data;
   
  g_mutex_lock (&self->idle_id_mutex);
  // do stuff with self
  self->idle_id = 0;
  g_mutex_unlock (&self->idle_id_mutex);
   
  return G_SOURCE_REMOVE;
}
 
static void
some_widget_do_stuff_later (SomeWidget *self)
{
  g_mutex_lock (&self->idle_id_mutex);
  self->idle_id = g_idle_add (idle_callback, self);
  g_mutex_unlock (&self->idle_id_mutex);
}
 
static void
some_widget_init (SomeWidget *self)
{
  g_mutex_init (&self->idle_id_mutex);

  // ...
}

static void
some_widget_finalize (GObject *object)
{
  SomeWidget *self = SOME_WIDGET (object);
   
  if (self->idle_id)
    g_source_remove (self->idle_id);
   
  g_mutex_clear (&self->idle_id_mutex);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

      This will fail in a multi-threaded application if the widget is destroyed before the idle handler fires due to the use after free in the callback. A solution, to this particular problem, is to check to if the source has already been destroy within the callback.

      static gboolean
idle_callback (gpointer data)
{
  SomeWidget *self = data;
  
  g_mutex_lock (&self->idle_id_mutex);
  if (!g_source_is_destroyed (g_main_current_source ()))
    {
      // do stuff with self
    }
  g_mutex_unlock (&self->idle_id_mutex);
  
  return FALSE;
}

      Calls to this function from a thread other than the one acquired by the GLib.MainContext the GLib.Source is attached to are typically redundant, as the source could be destroyed immediately after this function returns. However, once a source is destroyed it cannot be un-destroyed, so this function can be used for opportunistic checks from any thread.

      Returns:
      true if the source has been destroyed, false otherwise
      Since:
      2.12

    • modifyUnixFd

      public void modifyUnixFd(MemorySegment tag, Set<IOCondition> newEvents)

      Updates the event mask to watch for the file descriptor identified by tag.

      The tag is the tag returned from addUnixFd(int, Set).

      If you want to remove a file descriptor, don’t set its event mask to zero. Instead, call removeUnixFd(MemorySegment).

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      tag - the tag from addUnixFd(int, Set)
      newEvents - the new event mask to watch
      Since:
      2.36

    • modifyUnixFd

      public void modifyUnixFd(MemorySegment tag, IOCondition... newEvents)

      Updates the event mask to watch for the file descriptor identified by tag.

      The tag is the tag returned from addUnixFd(int, Set).

      If you want to remove a file descriptor, don’t set its event mask to zero. Instead, call removeUnixFd(MemorySegment).

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      tag - the tag from addUnixFd(int, Set)
      newEvents - the new event mask to watch
      Since:
      2.36

    • queryUnixFd

      public Set<IOCondition> queryUnixFd(MemorySegment tag)

      Queries the events reported for the file descriptor corresponding to tag on this Source during the last poll.

      The return value of this function is only defined when the function is called from the check or dispatch functions for source.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      tag - the tag from addUnixFd(int, Set)
      Returns:
      the conditions reported on the file descriptor
      Since:
      2.36

    • ref

      public Source ref()
      Increases the reference count on a source by one.
      Returns:
      this Source

    • removeChildSource

      public void removeChildSource(Source childSource)

      Detaches childSource from this Source and destroys it.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      Parameters:
      childSource - a source previously passed to addChildSource(Source)
      Since:
      2.28

    • removePoll

      public void removePoll(PollFD fd)

      Removes a file descriptor from the set of file descriptors polled for this source.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      Parameters:
      fd - a GLib.PollFD structure previously passed to addPoll(PollFD)

    • removeUnixFd

      public void removeUnixFd(MemorySegment tag)

      Reverses the effect of a previous call to addUnixFd(int, Set).

      You only need to call this if you want to remove a file descriptor from being watched while keeping the same source around. In the normal case you will just want to destroy the source.

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      As the name suggests, this function is not available on Windows.

      Parameters:
      tag - the tag from addUnixFd(int, Set)
      Since:
      2.36

    • setCallback

      public void setCallback(@Nullable SourceFunc func)

      Sets the callback function for a source. The callback for a source is called from the source’s dispatch function.

      The exact type of func depends on the type of source; ie. you should not count on func being called with data as its first parameter. Cast func with GLib.SOURCEFUNC to avoid warnings about incompatible function types.

      See main loop memory management for details on how to handle memory management of data.

      Typically, you won’t use this function. Instead use functions specific to the type of source you are using, such as GLib.idleAdd(int, SourceFunc) or GLib.timeoutAdd(int, int, SourceFunc).

      It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns.

      Note that destroy() for a currently attached source has the effect of also unsetting the callback.

      Parameters:
      func - a callback function

    • setCallbackIndirect

      public void setCallbackIndirect(@Nullable MemorySegment callbackData, SourceCallbackFuncs callbackFuncs)

      Sets the callback function storing the data as a reference counted callback ‘object’.

      This is used internally. Note that calling setCallbackIndirect(MemorySegment, SourceCallbackFuncs) assumes an initial reference count on callbackData, and thus callback_funcs->unref will eventually be called once more than callback_funcs->ref.

      It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns.

      Parameters:
      callbackData - pointer to callback data ‘object’
      callbackFuncs - functions for reference counting callbackData and getting the callback and data

    • setCanRecurse

      public void setCanRecurse(boolean canRecurse)

      Sets whether a source can be called recursively.

      If canRecurse is true, then while the source is being dispatched then this source will be processed normally. Otherwise, all processing of this source is blocked until the dispatch function returns.

      Parameters:
      canRecurse - whether recursion is allowed for this source

    • setDisposeFunction

      public void setDisposeFunction(@Nullable SourceDisposeFunc dispose)

      Set dispose as dispose function on source.

      The dispose function will be called once the reference count of this Source reaches zero but before any of the state of the source is freed, especially before the finalize function (set as part of the GLib.SourceFuncs) is called.

      This means that at this point this Source is still a valid GLib.Source and it is allow for the reference count to increase again until dispose returns.

      The dispose function can be used to clear any ‘weak’ references to the this Source in other data structures in a thread-safe way where it is possible for another thread to increase the reference count of this Source again while it is being freed.

      The finalize function can not be used for this purpose as at that point this Source is already partially freed and not valid any more.

      This should only ever be called from GLib.Source implementations.

      Parameters:
      dispose - dispose function to set on the source
      Since:
      2.64

    • setFuncs

      public void setFuncs(SourceFuncs funcs)

      Sets the source functions of an unattached source.

      These can be used to override the default implementations for the type of source.

      Parameters:
      funcs - the new source functions
      Since:
      2.12

    • setName

      public void setName(String name)

      Sets a name for the source, used in debugging and profiling.

      The name defaults to NULL.

      The source name should describe in a human-readable way what the source does. For example, ‘X11 event queue’ or ‘GTK repaint idle handler’.

      It is permitted to call this function multiple times, but is not recommended due to the potential performance impact. For example, one could change the name in the check function of a GLib.SourceFuncs to include details like the event type in the source name.

      Use caution if changing the name while another thread may be accessing it with getName(); that function does not copy the value, and changing the value will free it while the other thread may be attempting to use it.

      Also see setStaticName(String).

      Parameters:
      name - debug name for the source
      Since:
      2.26

    • setPriority

      public void setPriority(int priority)

      Sets the priority of a source.

      While the main loop is being run, a source will be dispatched if it is ready to be dispatched and no sources at a higher (numerically smaller) priority are ready to be dispatched.

      A child source always has the same priority as its parent. It is not permitted to change the priority of a source once it has been added as a child of another source.

      Parameters:
      priority - the new priority

    • setReadyTime

      public void setReadyTime(long readyTime)

      Sets a source to be dispatched when the given monotonic time is reached (or passed).

      If the monotonic time is in the past (as it always will be if readyTime is 0) then the source will be dispatched immediately.

      If readyTime is -1 then the source is never woken up on the basis of the passage of time.

      Dispatching the source does not reset the ready time. You should do so yourself, from the source dispatch function.

      Note that if you have a pair of sources where the ready time of one suggests that it will be delivered first but the priority for the other suggests that it would be delivered first, and the ready time for both sources is reached during the same main context iteration, then the order of dispatch is undefined.

      It is a no-op to call this function on a GLib.Source which has already been destroyed with destroy().

      This API is only intended to be used by implementations of GLib.Source. Do not call this API on a GLib.Source that you did not create.

      Parameters:
      readyTime - the monotonic time at which the source will be ready; 0 for ‘immediately’, -1 for ‘never’
      Since:
      2.36

    • setStaticName

      public void setStaticName(String name)
      A variant of setName(String) that does not duplicate the name, and can only be used with string literals.
      Parameters:
      name - debug name for the source
      Since:
      2.70

    • unref

      public void unref()

      Decreases the reference count of a source by one.

      If the resulting reference count is zero the source and associated memory will be destroyed.