Tracker Miner Library Reference Manual: TrackerMinerFS

## TrackerMinerFS TrackerMinerFS — Abstract base class for filesystem miners |

## Synopsis

    #include <libtracker-miner/tracker-miner.h>

    struct              TrackerMinerFS;
                        TrackerMinerFSClass;
    void                tracker_miner_fs_add_directory_without_parent
                                                            (TrackerMinerFS *fs,
                                                             GFile *file);
    void                tracker_miner_fs_check_directory    (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean check_parents);
    void                tracker_miner_fs_check_directory_with_priority
                                                            (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gint priority,
                                                             gboolean check_parents);
    void                tracker_miner_fs_check_file         (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean check_parents);
    void                tracker_miner_fs_check_file_with_priority
                                                            (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gint priority,
                                                             gboolean check_parents);
    void                tracker_miner_fs_directory_add      (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean recurse);
    gboolean            tracker_miner_fs_directory_remove   (TrackerMinerFS *fs,
                                                             GFile *file);
    gboolean            tracker_miner_fs_directory_remove_full
                                                            (TrackerMinerFS *fs,
                                                             GFile *file);
    void                tracker_miner_fs_file_notify        (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             const GError *error);
    void                tracker_miner_fs_force_mtime_checking
                                                            (TrackerMinerFS *fs,
                                                             GFile *directory);
    void                tracker_miner_fs_force_recheck      (TrackerMinerFS *fs);
    TrackerIndexingTree * tracker_miner_fs_get_indexing_tree
                                                            (TrackerMinerFS *fs);
    gboolean            tracker_miner_fs_get_initial_crawling
                                                            (TrackerMinerFS *fs);
    gboolean            tracker_miner_fs_get_mtime_checking (TrackerMinerFS *fs);
    const gchar *       tracker_miner_fs_get_parent_urn     (TrackerMinerFS *fs,
                                                             GFile *file);
    gdouble             tracker_miner_fs_get_throttle       (TrackerMinerFS *fs);
    const gchar *       tracker_miner_fs_get_urn            (TrackerMinerFS *fs,
                                                             GFile *file);
    gboolean            tracker_miner_fs_has_items_to_process
                                                            (TrackerMinerFS *fs);
    gchar *             tracker_miner_fs_query_urn          (TrackerMinerFS *fs,
                                                             GFile *file);
    void                tracker_miner_fs_set_initial_crawling
                                                            (TrackerMinerFS *fs,
                                                             gboolean do_initial_crawling);
    void                tracker_miner_fs_set_mtime_checking (TrackerMinerFS *fs,
                                                             gboolean mtime_checking);
    void                tracker_miner_fs_set_throttle       (TrackerMinerFS *fs,
                                                             gdouble throttle);
    void                tracker_miner_fs_writeback_file     (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             GStrv rdf_types,
                                                             GPtrArray *results);
    void                tracker_miner_fs_writeback_notify   (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             const GError *error);

## Object Hierarchy

      GObject
       +----TrackerMiner
             +----TrackerMinerFS

## Implemented Interfaces

TrackerMinerFS implements GInitable.

## Properties

      "initial-crawling"         gboolean              : Read / Write
      "mtime-checking"           gboolean              : Read / Write / Construct
      "processing-pool-ready-limit" guint                 : Read / Write / Construct
      "processing-pool-wait-limit" guint                 : Read / Write / Construct
      "throttle"                 gdouble               : Read / Write

## Signals

      "finished"                                       : Run Last
      "ignore-next-update-file"                        : Run Last
      "process-file"                                   : Run Last
      "process-file-attributes"                        : Run Last
      "writeback-file"                                 : Run Last

## Description

TrackerMinerFS is an abstract base class for miners that collect data from the filesystem, all the filesystem crawling and monitoring is abstracted away, leaving to implementations the decisions of what directories/files should it process, and the actual data extraction.

## Details

### struct TrackerMinerFS

    struct TrackerMinerFS;

Abstract miner implementation to get data from the filesystem.

### TrackerMinerFSClass

    typedef struct {
    	TrackerMinerClass parent;

    	gboolean (* process_file)             (TrackerMinerFS       *fs,
    	                                       GFile                *file,
    	                                       TrackerSparqlBuilder *builder,
    	                                       GCancellable         *cancellable);
    	gboolean (* ignore_next_update_file)  (TrackerMinerFS       *fs,
    	                                       GFile                *file,
    	                                       TrackerSparqlBuilder *builder,
    	                                       GCancellable         *cancellable);
    	void     (* finished)                 (TrackerMinerFS       *fs);
    	gboolean (* process_file_attributes)  (TrackerMinerFS       *fs,
    	                                       GFile                *file,
    	                                       TrackerSparqlBuilder *builder,
    	                                       GCancellable         *cancellable);
    	gboolean (* writeback_file)           (TrackerMinerFS       *fs,
    	                                       GFile                *file,
    	                                       GStrv                 rdf_types,
    	                                       GPtrArray            *results);
    } TrackerMinerFSClass;

Prototype for the abstract class, `process_file` must be implemented in the deriving class in order to actually extract data.

TrackerMinerClass `parent`; | parent object class
`process_file` () | Called when the metadata associated to a file is requested.
`ignore_next_update_file` () | Called after a writeback event happens on a file (deprecated since 0.12).
`finished` () | Called when all processing has been performed.
`process_file_attributes` () | Called when the metadata associated with a file's attributes changes, for example, the mtime.
`writeback_file` () | Called when a file must be written back

### tracker_miner_fs_add_directory_without_parent ()

    void                tracker_miner_fs_add_directory_without_parent
                                                            (TrackerMinerFS *fs,
                                                             GFile *file);

Tells the miner-fs that the given GFile corresponds to a directory which was created in the store without a specific parent object. In this case, when regenerating internal caches, an extra query will be done so that these elements are taken into account.

`fs` : | a TrackerMinerFS
`file` : | a GFile

Since 0.10

### tracker_miner_fs_check_directory ()

    void                tracker_miner_fs_check_directory    (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean check_parents);

Tells the filesystem miner to check and index a directory, this file must be part of the usual crawling directories of TrackerMinerFS. See `tracker_miner_fs_directory_add()`.

`fs` : | a TrackerMinerFS
`file` : | GFile for the directory to check
`check_parents` : | whether to check parents and eligibility or not

Since 0.10

### tracker_miner_fs_check_directory_with_priority ()

    void                tracker_miner_fs_check_directory_with_priority
                                                            (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gint priority,
                                                             gboolean check_parents);

Tells the filesystem miner to check and index a directory at a given priority, this file must be part of the usual crawling directories of TrackerMinerFS. See `tracker_miner_fs_directory_add()`.

`fs` : | a TrackerMinerFS
`file` : | GFile for the directory to check
`priority` : | the priority of the check task
`check_parents` : | whether to check parents and eligibility or not

Since 0.10

### tracker_miner_fs_check_file ()

    void                tracker_miner_fs_check_file         (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean check_parents);

Tells the filesystem miner to check and index a file, this file must be part of the usual crawling directories of TrackerMinerFS. See `tracker_miner_fs_directory_add()`.

`fs` : | a TrackerMinerFS
`file` : | GFile for the file to check
`check_parents` : | whether to check parents and eligibility or not

Since 0.10

### tracker_miner_fs_check_file_with_priority ()

    void                tracker_miner_fs_check_file_with_priority
                                                            (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gint priority,
                                                             gboolean check_parents);

Tells the filesystem miner to check and index a file at a given priority, this file must be part of the usual crawling directories of TrackerMinerFS. See `tracker_miner_fs_directory_add()`.

`fs` : | a TrackerMinerFS
`file` : | GFile for the file to check
`priority` : | the priority of the check task
`check_parents` : | whether to check parents and eligibility or not

Since 0.10

### tracker_miner_fs_directory_add ()

    void                tracker_miner_fs_directory_add      (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             gboolean recurse);

Tells the filesystem miner to inspect a directory.

`fs` : | a TrackerMinerFS
`file` : | GFile for the directory to inspect
`recurse` : | whether the directory should be inspected recursively

Since 0.8

### tracker_miner_fs_directory_remove ()

    gboolean            tracker_miner_fs_directory_remove   (TrackerMinerFS *fs,
                                                             GFile *file);

Removes a directory from being inspected by `fs`. Note that only directory watches are removed.

`fs` : | a TrackerMinerFS
`file` : | GFile for the directory to be removed
Returns : | `TRUE` if the directory was successfully removed.

Since 0.8

### tracker_miner_fs_directory_remove_full ()

    gboolean            tracker_miner_fs_directory_remove_full
                                                            (TrackerMinerFS *fs,
                                                             GFile *file);

Removes a directory from being inspected by `fs`, and removes all associated metadata of the directory (and its contents) from the store.

`fs` : | a TrackerMinerFS
`file` : | GFile for the directory to be removed
Returns : | `TRUE` if the directory was successfully removed.

Since 0.10

### tracker_miner_fs_file_notify ()

    void                tracker_miner_fs_file_notify        (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             const GError *error);

Notifies `fs` that all processing on `file` has been finished, if any error happened during file data processing, it should be passed in `error`, else that parameter will contain `NULL` to reflect success.

`fs` : | a TrackerMinerFS
`file` : | a GFile
`error` : | a GError with the error that happened during processing, or `NULL`.

Since 0.8

### tracker_miner_fs_force_mtime_checking ()

    void                tracker_miner_fs_force_mtime_checking
                                                            (TrackerMinerFS *fs,
                                                             GFile *directory);

Tells `fs` to force mtime checking (regardless of the global mtime check configuration) on the given `directory`.

`fs` : | a TrackerMinerFS
`directory` : | a GFile representing the directory

Since 0.12

### tracker_miner_fs_force_recheck ()

    void                tracker_miner_fs_force_recheck      (TrackerMinerFS *fs);

### tracker_miner_fs_get_indexing_tree ()

    TrackerIndexingTree * tracker_miner_fs_get_indexing_tree
                                                            (TrackerMinerFS *fs);

Returns the TrackerIndexingTree which determines what files/directories are indexed by `fs`

`fs` : | a TrackerMinerFS
Returns : | The TrackerIndexingTree holding the indexing configuration. [transfer none]

### tracker_miner_fs_get_initial_crawling ()

    gboolean            tracker_miner_fs_get_initial_crawling
                                                            (TrackerMinerFS *fs);

### tracker_miner_fs_get_mtime_checking ()

    gboolean            tracker_miner_fs_get_mtime_checking (TrackerMinerFS *fs);

`fs` : | a TrackerMinerFS
Returns : | TRUE if mtime checks for directories against the database are done when `fs` crawls the file system, otherwise FALSE.

Since 0.10

### tracker_miner_fs_get_parent_urn ()

    const gchar *       tracker_miner_fs_get_parent_urn     (TrackerMinerFS *fs,
                                                             GFile *file);

If `file` is currently being processed by `fs`, this function will return the parent folder URN if any. This function is useful to set the nie:belongsToContainer relationship. The processing order of TrackerMinerFS guarantees that a folder has been already fully processed for indexing before any children is processed, so most usually this function should return non-`NULL`.

`fs` : | a TrackerMinerFS
`file` : | a GFile obtained in "process-file"
Returns : | The parent folder URN, or `NULL`. [transfer none]

Since 0.8

### tracker_miner_fs_get_throttle ()

    gdouble             tracker_miner_fs_get_throttle       (TrackerMinerFS *fs);

Gets the current throttle value. see `tracker_miner_fs_set_throttle()`.

`fs` : | a TrackerMinerFS
Returns : | current throttle value.

Since 0.8

### tracker_miner_fs_get_urn ()

    const gchar *       tracker_miner_fs_get_urn            (TrackerMinerFS *fs,
                                                             GFile *file);

If the item exists in the store, this function retrieves the URN for a GFile being currently processed.

If `file` is not being currently processed by `fs`, or doesn't exist in the store yet, `NULL` will be returned.

`fs` : | a TrackerMinerFS
`file` : | a GFile obtained in "process-file"
Returns : | The URN containing the data associated to `file`, or `NULL`. [transfer none]

Since 0.8

### tracker_miner_fs_has_items_to_process ()

    gboolean            tracker_miner_fs_has_items_to_process
                                                            (TrackerMinerFS *fs);

`fs` : | a TrackerMinerFS
Returns : | TRUE if there are items to process in the internal queues, otherwise FALSE.

Since 0.10

### tracker_miner_fs_query_urn ()

    gchar *             tracker_miner_fs_query_urn          (TrackerMinerFS *fs,
                                                             GFile *file);

If the item exists in the store, this function retrieves the URN of the given GFile

If `file` doesn't exist in the store yet, `NULL` will be returned.

`fs` : | a TrackerMinerFS
`file` : | a GFile
Returns : | A newly allocated string with the URN containing the data associated to `file`, or `NULL`. [transfer full]

Since 0.10

### tracker_miner_fs_set_initial_crawling ()

    void                tracker_miner_fs_set_initial_crawling
                                                            (TrackerMinerFS *fs,
                                                             gboolean do_initial_crawling);

### tracker_miner_fs_set_mtime_checking ()

    void                tracker_miner_fs_set_mtime_checking (TrackerMinerFS *fs,
                                                             gboolean mtime_checking);

Tells the miner-fs that during the crawling phase, directory mtime checks should or shouldn't be performed against the database to make sure we have the most up to date version of the file being checked at the time. Setting this to FALSE can dramatically improve the start up the crawling of the `fs`.

The down side is that using this consistently means that some files on the disk may be out of date with files in the database.

The main purpose of this function is for systems where a `fs` is running the entire time and where it is very unlikely that a file could be changed outside between startup and shutdown of the process using this API.

The default if not set directly is that `mtime_checking` is TRUE.

`fs` : | a TrackerMinerFS
`mtime_checking` : | a gboolean

Since 0.10

### tracker_miner_fs_set_throttle ()

    void                tracker_miner_fs_set_throttle       (TrackerMinerFS *fs,
                                                             gdouble throttle);

Tells the filesystem miner to throttle its operations. a value of 0 means no throttling at all, so the miner will perform operations at full speed, 1 is the slowest value.

`fs` : | a TrackerMinerFS
`throttle` : | throttle value, between 0 and 1

Since 0.8

### tracker_miner_fs_writeback_file ()

    void                tracker_miner_fs_writeback_file     (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             GStrv rdf_types,
                                                             GPtrArray *results);

Tells the filesystem miner to writeback a file.

`fs` : | a TrackerMinerFS
`file` : | GFile for the file to check
`rdf_types` : | A GStrv with rdf types
`results` : | A array of results from the preparation query. [element-type GStrv]

Since 0.10.20

### tracker_miner_fs_writeback_notify ()

    void                tracker_miner_fs_writeback_notify   (TrackerMinerFS *fs,
                                                             GFile *file,
                                                             const GError *error);

Notifies `fs` that all writing back on `file` has been finished, if any error happened during file data processing, it should be passed in `error`, else that parameter will contain `NULL` to reflect success.

`fs` : | a TrackerMinerFS
`file` : | a GFile
`error` : | a GError with the error that happened during processing, or `NULL`.

Since 0.10.20

## Property Details

### The `"initial-crawling"` property

      "initial-crawling"         gboolean              : Read / Write

Whether to perform initial crawling or not.

Default value: TRUE

### The `"mtime-checking"` property

      "mtime-checking"           gboolean              : Read / Write / Construct

Whether to perform mtime checks during initial crawling or not.

Default value: TRUE

### The `"processing-pool-ready-limit"` property

      "processing-pool-ready-limit" guint                 : Read / Write / Construct

Maximum number of SPARQL updates that can be merged in a single connection to the store.

Allowed values: >= 1

Default value: 1

### The `"processing-pool-wait-limit"` property

      "processing-pool-wait-limit" guint                 : Read / Write / Construct

Maximum number of files that can be concurrently processed by the upper layer.

Allowed values: >= 1

Default value: 1

### The `"throttle"` property

      "throttle"                 gdouble               : Read / Write

Modifier for the indexing speed, 0 is max speed.

Allowed values: [0,1]

Default value: 0

## Signal Details

### The `"finished"` signal

    void                user_function                      (TrackerMinerFS *miner_fs,
                                                            gdouble         elapsed,
                                                            guint           directories_found,
                                                            guint           directories_ignored,
                                                            guint           files_found,
                                                            guint           files_ignored,
                                                            gpointer        user_data)                : Run Last

The ::finished signal is emitted when `miner_fs` has finished all pending processing.

`miner_fs` : | the TrackerMinerFS
`elapsed` : | elapsed time since mining was started
`directories_found` : | number of directories found
`directories_ignored` : | number of ignored directories
`files_found` : | number of files found
`files_ignored` : | number of ignored files
`user_data` : | user data set when the signal handler was connected.

Since 0.8

### The `"ignore-next-update-file"` signal

    gboolean            user_function                      (TrackerMinerFS       *miner_fs,
                                                            GFile                *file,
                                                            TrackerSparqlBuilder *builder,
                                                            GCancellable         *cancellable,
                                                            gpointer              user_data)        : Run Last

### Warning

`TrackerMinerFS::ignore-next-update-file` is deprecated and should not be used in newly-written code. 0.12

The ::ignore-next-update-file signal is emitted whenever a file should be marked as to ignore on next update, and it's metadata prepared for that.

`builder` is the TrackerSparqlBuilder where all sparql updates to be performed for `file` will be appended.

`miner_fs` : | the TrackerMinerFS
`file` : | a GFile
`builder` : | a TrackerSparqlBuilder
`cancellable` : | a GCancellable
`user_data` : | user data set when the signal handler was connected.
Returns : | `TRUE` on success `FALSE` on failure

Since 0.8

### The `"process-file"` signal

    gboolean            user_function                      (TrackerMinerFS       *miner_fs,
                                                            GFile                *file,
                                                            TrackerSparqlBuilder *builder,
                                                            GCancellable         *cancellable,
                                                            gpointer              user_data)        : Run Last

The ::process-file signal is emitted whenever a file should be processed, and it's metadata extracted.

`builder` is the TrackerSparqlBuilder where all sparql updates to be performed for `file` will be appended.

This signal allows both synchronous and asynchronous extraction, in the synchronous case `cancellable` can be safely ignored. In either case, on successful metadata extraction, implementations must call `tracker_miner_fs_file_notify()` to indicate that processing has finished on `file`, so the miner can execute the SPARQL updates and continue processing other files.

`miner_fs` : | the TrackerMinerFS
`file` : | a GFile
`builder` : | a TrackerSparqlBuilder
`cancellable` : | a GCancellable
`user_data` : | user data set when the signal handler was connected.
Returns : | `TRUE` if the file is accepted for processing, `FALSE` if the file should be ignored.

Since 0.8

### The `"process-file-attributes"` signal

    gboolean            user_function                      (TrackerMinerFS       *miner_fs,
                                                            GFile                *file,
                                                            TrackerSparqlBuilder *builder,
                                                            GCancellable         *cancellable,
                                                            gpointer              user_data)        : Run Last

The ::process-file-attributes signal is emitted whenever a file should be processed, but only the attribute-related metadata extracted.

`builder` is the TrackerSparqlBuilder where all sparql updates to be performed for `file` will be appended. For the properties being updated, the DELETE statements should be included as well.

This signal allows both synchronous and asynchronous extraction, in the synchronous case `cancellable` can be safely ignored. In either case, on successful metadata extraction, implementations must call `tracker_miner_fs_file_notify()` to indicate that processing has finished on `file`, so the miner can execute the SPARQL updates and continue processing other files.

`miner_fs` : | the TrackerMinerFS
`file` : | a GFile
`builder` : | a TrackerSparqlBuilder
`cancellable` : | a GCancellable
`user_data` : | user data set when the signal handler was connected.
Returns : | `TRUE` if the file is accepted for processing, `FALSE` if the file should be ignored.

Since 0.10

### The `"writeback-file"` signal

    gboolean            user_function                      (TrackerMinerFS *miner_fs,
                                                            GFile          *file,
                                                            GStrv           rdf_types,
                                                            GPtrArray      *results,
                                                            GCancellable   *cancellable,
                                                            gpointer        user_data)        : Run Last

The ::writeback-file signal is emitted whenever a file must be written back

`miner_fs` : | the TrackerMinerFS
`file` : | a GFile
`rdf_types` : | the set of RDF types
`results` : | a set of results prepared by the preparation query. [element-type GStrv]
`cancellable` : | a GCancellable
`user_data` : | user data set when the signal handler was connected.
Returns : | `TRUE` on success, `FALSE` otherwise

Since 0.10.20