FmJob: Libfm Reference Manual

## FmJob FmJob — Base class of all kinds of asynchronous jobs. |

## Functions

gpointer | (*FmJobCallMainThreadFunc) ()
gint | fm_job_ask ()
gint | fm_job_ask_valist ()
gint | fm_job_askv ()
gpointer | fm_job_call_main_thread ()
void | fm_job_cancel ()
FmJobErrorAction | fm_job_emit_error ()
void | fm_job_finish ()
GCancellable * | fm_job_get_cancellable ()
void | fm_job_init_cancellable ()
gboolean | fm_job_is_cancelled ()
gboolean | fm_job_is_running ()
gboolean | fm_job_pause ()
void | fm_job_resume ()
gboolean | fm_job_run_async ()
gboolean | fm_job_run_sync ()
gboolean | fm_job_run_sync_with_mainloop ()
void | fm_job_set_cancellable ()

## Signals

gint | ask | Run Last
void | cancelled | Run First
guint | error | Run Last
void | finished | Run First

## Types and Values

struct | FmJob
struct | FmJobClass
enum | FmJobErrorAction
enum | FmJobErrorSeverity

## Object Hierarchy

        GObject
        ╰── FmJob
            ├── FmDeepCountJob
            ├── FmDirListJob
            ├── FmFileInfoJob
            ╰── FmFileOpsJob

## Description

`include` : libfm/fm.h

The FmJob can be used to create asynchronous jobs performing some time-consuming tasks in another worker thread. To run a FmJob in another thread you simply call `fm_job_run_async()`, and then the task will be done in another worker thread. Later, when the job is finished, “finished” signal is emitted. When the job is still running, it's possible to cancel it from main thread by calling `fm_job_cancel()`. Then, “cancelled” signal will be emitted before emitting “finished” signal. You can also run the job in blocking fashion instead of running it asynchronously by calling `fm_job_run_sync()`.

## Functions

### FmJobCallMainThreadFunc ()

    gpointer
    (*FmJobCallMainThreadFunc) (FmJob *job,
                                gpointer user_data);

### fm_job_ask ()

    gint
    fm_job_ask (FmJob *job,
                const char *question,
                ...);

Asks the user for some interactions. The user will have a list of available options and should make a choice.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | the job that calls main thread |
question | the text to ask the user |
... | list of choices to give the user |

#### Returns

user's choice.

Since: 0.1.0

### fm_job_ask_valist ()

    gint
    fm_job_ask_valist (FmJob *job,
                       const char *question,
                       va_list options);

Asks the user for some interactions. The user will have a list of available options and should make a choice.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | the job that calls main thread |
question | the text to ask the user |
options | list of choices to give the user |

#### Returns

user's choice.

Since: 0.1.0

### fm_job_askv ()

    gint
    fm_job_askv (FmJob *job,
                 const char *question,
                 gchar * const *options);

Asks the user for some interactions. The user will have a list of available options and should make a choice.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | the job that calls main thread |
question | the text to ask the user |
options | list of choices to give the user |

#### Returns

user's choice.

Since: 0.1.0

### fm_job_call_main_thread ()

    gpointer
    fm_job_call_main_thread (FmJob *job,
                             FmJobCallMainThreadFunc func,
                             gpointer user_data);

Stops calling thread, waits main thread for idle, passes `user_data` to callback `func` in main thread, gathers result of callback, and returns it to caller.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | the job that calls main thread |
func | callback to run from main thread |
user_data | user data for the callback |

#### Returns

return value from running `func` .

Since: 0.1.0

### fm_job_cancel ()

    void
    fm_job_cancel (FmJob *job);

Cancels the `job` .

#### Parameters

job | a job to cancel |

Since: 0.1.0

### fm_job_emit_error ()

    FmJobErrorAction
    fm_job_emit_error (FmJob *job,
                       GError *err,
                       FmJobErrorSeverity severity);

Emits an “error” signal in the main thread to notify it when an error occurs. The return value of this function is the return value returned by the connected signal handlers. If `severity` is FM_JOB_ERROR_CRITICAL, the returned value is ignored and `fm_job_cancel()` is called to abort the job. Otherwise, the signal handler of this error can return FM_JOB_RETRY to ask for retrying the failed operation, return FM_JOB_CONTINUE to ignore the error and continue the remaining job, or return FM_JOB_ABORT to abort the job. If FM_JOB_ABORT is returned by the signal handler, `fm_job_cancel()` will be called in `fm_job_emit_error()`.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | a job that emitted the signal |
err | an error descriptor |
severity | severity of the error |

#### Returns

action that should be performed on that error.

Since: 0.1.0

### fm_job_finish ()

    void
    fm_job_finish (FmJob *job);

Schedules the finishing of job. Once this function is called the `job` becomes invalid for the caller and should be not used anymore.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

This function should be called from working thread only.

#### Parameters

job | the job that was finished |

Since: 0.1.0

### fm_job_get_cancellable ()

    GCancellable *
    fm_job_get_cancellable (FmJob *job);

Get an existing GCancellable object from `job` for use with gio in another job by calling `fm_job_set_cancellable()`. This can be used when you wish to share a cancellable object among different jobs.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

#### Parameters

job | the job to inspect |

#### Returns

a GCancellable object if it was initialized for `job` .

Since: 0.1.9

### fm_job_init_cancellable ()

    void
    fm_job_init_cancellable (FmJob *job);

Used by derived classes to implement `FmJobClass:`run()`` using gio inside. This API tries to initialize a GCancellable object for use with gio and should only be called once in the constructor of derived classes which require the use of GCancellable.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

#### Parameters

job | the job to init |

Since: 0.1.0

### fm_job_is_cancelled ()

    gboolean
    fm_job_is_cancelled (FmJob *job);

Checks if the job is already cancelled.

#### Parameters

job | the job to inspect |

#### Returns

`TRUE` if the job is already cancelled.

Since: 0.1.9

### fm_job_is_running ()

    gboolean
    fm_job_is_running (FmJob *job);

Checks if the job is still running.

#### Parameters

job | the job to inspect |

#### Returns

`TRUE` if the job is still running.

Since: 0.1.9

### fm_job_pause ()

    gboolean
    fm_job_pause (FmJob *job);

Locks execution of job until next call to `fm_job_resume()`. This call may be used from thread different from the thread where the job runs in. This call may be done again (but have no extra effect) from the same thread. Any other usage may lead to deadlock.

#### Parameters

job | a job to apply |

#### Returns

`FALSE` if job cannot be locked.

Since: 1.2.0

### fm_job_resume ()

    void
    fm_job_resume (FmJob *job);

Unlocks execution of `job` that was made by previous call to `fm_job_pause()`. This call may be used only from the same thread where previous `fm_job_pause()` was made. Any other usage may lead to deadlock.

#### Parameters

job | a job to apply |

Since: 1.2.0

### fm_job_run_async ()

    gboolean
    fm_job_run_async (FmJob *job);

Starts the `job` asyncronously creating new thread. If job starts successfully then the “finished” signal will be emitted when `job` is either succeeded or was cancelled. If `job` could not be started then “cancelled” signal is emitted before return from this function.

#### Parameters

job | a job to run |

#### Returns

`TRUE` if job started successfully.

Since: 0.1.0

### fm_job_run_sync ()

    gboolean
    fm_job_run_sync (FmJob *job);

Runs the `job` in current thread in a blocking fashion. The job will emit either “cancelled” signal if job was cancelled or “finished” signal if it finished successfully.

#### Parameters

job | a job to run |

#### Returns

`TRUE` if `job` ran successfully.

Since: 0.1.0

### fm_job_run_sync_with_mainloop ()

    gboolean
    fm_job_run_sync_with_mainloop (FmJob *job);

Runs the `job` in current thread in a blocking fashion and an additional mainloop being created to prevent blocking of user interface. If `job` started successfully then “finished” signal is emitted when `job` is either succeeded or was cancelled. Note: using this API from within GTK main loop will lead to deadlock therefore if it is a GTK application then caller should unlock GDK threads before calling this API and lock them back after return from it. This statement is valid for any GTK application that uses locks.

#### Parameters

job | a job to run |

#### Returns

`TRUE` if job started successfully.

Since: 0.1.1

### fm_job_set_cancellable ()

    void
    fm_job_set_cancellable (FmJob *job,
                            GCancellable *cancellable);

Lets the job to use an existing `cancellable` object. This can be used when you wish to share a cancellable object among different jobs. This should only be called before the `job` is launched.

This APIs is private to FmJob and should only be used in the implementation of classes derived from FmJob.

#### Parameters

job | the job to set |
cancellable | a shared cancellable object. | [allow-none]

Since: 0.1.0

## Types and Values

### struct FmJob

    struct FmJob;

### struct FmJobClass

    struct FmJobClass {
        GObjectClass parent_class;

        /* the class closures for signals */
        void (*finished)(FmJob* job);
        guint (*error)(FmJob* job, GError* err, guint severity);
                    /* guint above are: FmJobErrorAction and FmJobErrorSeverity */
        void (*cancelled)(FmJob* job);
        gint (*ask)(FmJob* job, const gchar* question, gchar* const *options);

        /* routines used by methods */
        gboolean (*run_async)(FmJob* job); /* for fm_job_run_async() */
        gboolean (*run)(FmJob* job); /* for any fm_job_run_*() */
        void (*cancel)(FmJob* job); /* for fm_job_cancel() */
    };

#### Members

`finished` () | the class closure for the “finished” signal. |
`error` () | the class closure for the “error” signal. |
`cancelled` () | the class closure for the “cancelled” signal. |
`ask` () | the class closure for the “ask” signal. |
`run_async` () | the `run_async` function called to create a thread for the job execution. Returns `TRUE` if thread was created successfully. The most probably should be not overridden by any derived class. |
`run` () | the `run` function is called to perform actual job actions. Returns value that will be returned from call `fm_job_run_sync()`. Should be set by any class derived from FmJob. |
`cancel` () | the `cancel` function is called when the job is cancelled. It can perform some class-specific operations then. |

### enum FmJobErrorAction

The action that should be performed after error happened. Usually chosen by user.

#### Members

FM_JOB_CONTINUE | ignore the error and continue remaining work |
FM_JOB_RETRY | retry the previously failed operation. (not every kind of job support this) |
FM_JOB_ABORT | abort the whole job |

### enum FmJobErrorSeverity

#### Members

FM_JOB_ERROR_WARNING | not an error, just a warning |
FM_JOB_ERROR_MILD | no big deal, can be ignored most of the time |
FM_JOB_ERROR_MODERATE | moderate errors |
FM_JOB_ERROR_SEVERE | severe errors, whether to abort operation depends on error handlers |
FM_JOB_ERROR_CRITICAL | critical errors, the operation is aborted |

## Signal Details

### The `“ask”` signal

    gint
    user_function (FmJob   *job,
                   gpointer question,
                   gpointer options,
                   gpointer user_data)

The “ask” signal is emitted when the job asks for some user interactions. The user then will have a list of available `options` . If there is more than one handler connected to the signal then only one of them will receive it.

#### Parameters

job | a job that emitted the signal |
question | (const gchar *) a question to ask user |
options | (gchar* const *) list of choices to ask user |
user_data | user data set when the signal handler was connected. |

#### Returns

user's choice.

Flags: Run Last

Since: 0.1.0

### The `“cancelled”` signal

    void
    user_function (FmJob   *job,
                   gpointer user_data)

The “cancelled” signal is emitted when the job is cancelled or aborted due to critical errors.

#### Parameters

job | a job that emitted the signal |
user_data | user data set when the signal handler was connected. |

Flags: Run First

Since: 0.1.0

### The `“error”` signal

    guint
    user_function (FmJob   *job,
                   GError  *error,
                   guint    severity,
                   gpointer user_data)

The “error” signal is emitted when errors happen. A case if more than one handler is connected to this signal is ambiguous.

#### Parameters

job | a job that emitted the signal |
error | an error descriptor |
severity | FmJobErrorSeverity of the error |
user_data | user data set when the signal handler was connected. |

#### Returns

FmJobErrorAction that should be performed on that error.

Flags: Run Last

Since: 0.1.0

### The `“finished”` signal

    void
    user_function (FmJob   *job,
                   gpointer user_data)

The “finished” signal is emitted after the job is finished. The signal is never emitted if the fm_job_run_XXX function returned `FALSE`, in that case the “cancelled” signal will be emitted instead.

#### Parameters

job | a job that emitted the signal |
user_data | user data set when the signal handler was connected. |

Flags: Run First

Since: 0.1.0