hello-world/include/db.h File Reference

#include <glib.h>
#include <libermetadb/ermetadb.h>

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Data Structures
struct	thumbType
Defines
#define	IN
#define	OUT
#define	INOUT
Functions
erMetadb	open_database (const char *IN dir)
	Opens metadata database in directory.
void	close_database (erMetadb IN db)
	Closes an open metadata database in directory.
gboolean	load_file_metadata (erMetadb IN db, const gchar *IN filepath, const gchar *IN filename, GString *OUT title, GString *OUT author, thumbType *OUT small, thumbType *OUT medium)
	Loads the file metadata from database.
gboolean	save_file_metadata (erMetadb IN db, const gchar *IN filepath, const gchar *IN filename, GString *IN title, GString *IN author, thumbType *IN small, thumbType *IN medium)
	Saves the file metadata to database.
void	pixbuf_draw_rectangle (GdkPixbuf *pixbuf, gint xx, gint yy, gint ww, gint hh, gint color)
	Draw a rectangle border in a pixbuf.
gboolean	pixbuf_to_blob (GdkPixbuf *IN pixbuf, gchar **OUT buffer, gsize *OUT buf_size)
	Converts a GdkPixbuf* to a BLOB buffer.

---

Define Documentation

#define IN

File Name : db.h

Description: Metadb interface functions Copyright (C) 2009 iRex Technologies B.V. All rights reserved.

Definition at line 54 of file hello-world/include/db.h.

#define INOUT

Definition at line 56 of file hello-world/include/db.h.

#define OUT

Definition at line 55 of file hello-world/include/db.h.

---

Function Documentation

void close_database

(

erMetadb IN

db

)

Closes an open metadata database in directory.

---------------------------------------------------------------------------

Name : close_database

Parameters:

db

pointer to a valid erMetadb object

Returns:

--

--------------------------------------------------------------------------

Definition at line 102 of file hello-world/src/db.c.

References ermetadb_close(), and sync().

{
    g_assert ( NULL != db );
    
    ermetadb_close(db);
    // explicit sync since ermetadb_close_database does not flush to disk
    sync();
}

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gboolean load_file_metadata	(	erMetadb IN	db,
		const gchar *IN	filepath,
		const gchar *IN	filename,
		GString *OUT	title,
		GString *OUT	author,
		thumbType *OUT	small,
		thumbType *OUT	medium
	)

Loads the file metadata from database.

---------------------------------------------------------------------------

Name : load_file_metadata

Parameters:

	db	pointer to a valid erMetadb object
	filepath	filename for which to load metadata
	filename	filename for which to load metadata
	title	pointer to GString to store the title NULL -> title should not be retreived
	author	pointer to GString to store the author NULL -> author should not be retreived

Returns:

FALSE on failure, TRUE on success

--------------------------------------------------------------------------

Definition at line 112 of file hello-world/src/db.c.

References ER_OK, ermetadb_global_get_file(), ERRORPRINTF, FILE_AUTHOR, FILE_TITLE, METADATA_BLOB, METADATA_NULL, metadata_table_add_column(), metadata_table_find_column(), metadata_table_free, metadata_table_get_cell(), metadata_table_new(), METADATA_TEXT, THUMBNAIL_COLUMNS, THUMBNAIL_MEDIUM, THUMBNAIL_SMALL, metadata_cell::type, metadata_cell::v_blob, metadata_cell::v_text, and metadata_cell::value.

Referenced by do_example_db_actions().

{
    g_assert(db != NULL);
    g_assert(filename != NULL);

    metadata_table* name_table = metadata_table_new();
    g_return_val_if_fail( NULL != name_table, FALSE);

    // add columns, caller is owner of OUT parameters
    if (title   ) { metadata_table_add_column(name_table, FILE_TITLE       ); }
    if (author  ) { metadata_table_add_column(name_table, FILE_AUTHOR      ); }
    if (small   ) { metadata_table_add_column(name_table, THUMBNAIL_COLUMNS[THUMBNAIL_SMALL]);  }
    if (medium  ) { metadata_table_add_column(name_table, THUMBNAIL_COLUMNS[THUMBNAIL_MEDIUM]); }

    // query
    metadata_table* results_table = NULL; // must be NULL, created by function below
    int rc = ermetadb_global_get_file(db, filepath, filename, name_table, &results_table);

    if (rc != ER_OK)
    {
        ERRORPRINTF("ermetadb_get_file_metadata() returns [%d]", rc);
        metadata_table_free(name_table);
        metadata_table_free(results_table);
        return FALSE;
    }

    if (title) 
    {
        // Get title.
        const char *column = FILE_TITLE;
        int index = metadata_table_find_column(results_table, column);
        if (index >= 0)
        {
            const metadata_cell *cell = metadata_table_get_cell(results_table, index);

            if (cell && cell->type == METADATA_TEXT)
            {
                g_string_assign(title, cell->value.v_text->str );
            }
        }
        else
        {
            ERRORPRINTF("Cannot find column %s", column);
        }
    }

    if (author)
    {
        // get author
        const char* column = FILE_AUTHOR;
        int index = metadata_table_find_column(results_table, column);
        if (index >= 0)
        {
            const metadata_cell *cell = metadata_table_get_cell(results_table, index);

            if (cell && cell->type == METADATA_TEXT)
            {
                g_string_assign(author, cell->value.v_text->str );
            }
        }
        else
        {
            ERRORPRINTF("Cannot find column %s", column);
        }
    }

    if (small)
    {
        // get file thumbnail (medium)
        const char* column = THUMBNAIL_COLUMNS[THUMBNAIL_SMALL];
        int index = metadata_table_find_column(results_table, column);
        if (index >= 0)
        {
            const metadata_cell *cell = metadata_table_get_cell(results_table, index);

            if (cell && cell->type != METADATA_BLOB)
            {
                if (cell->type != METADATA_NULL) {
                    ERRORPRINTF("illegal cell type [%d] for thumbnail", cell->type);
                }
                small->data = NULL ;
                small->size = 0;
            }
            else {
                small->size = cell->value.v_blob.len;
                memcpy((guchar*) small->data, (guchar*) cell->value.v_blob.data, small->size);
            }
        }
        else
        {
            ERRORPRINTF("Cannot find column %s", column);
        }
    }

    if (medium)
    {
        // get file thumbnail (medium)
        const char* column = THUMBNAIL_COLUMNS[THUMBNAIL_MEDIUM];
        int index = metadata_table_find_column(results_table, column);
        if (index >= 0)
        {
            const metadata_cell *cell = metadata_table_get_cell(results_table, index);

            if (cell && cell->type != METADATA_BLOB)
            {
                if (cell->type != METADATA_NULL) {
                    ERRORPRINTF("illegal cell type [%d] for thumbnail", cell->type);
                }
                medium->data = NULL ;
                medium->size = 0;
            }
            else {
                medium->size = cell->value.v_blob.len;
                memcpy((guchar*) medium->data, (guchar*) cell->value.v_blob.data, medium->size);
            }
        }
        else
        {
            ERRORPRINTF("Cannot find column %s", column);
        }
    }

    // clean up
    metadata_table_free(name_table);
    metadata_table_free(results_table);

    return TRUE;
}

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erMetadb open_database

(

const char *IN

dir

)

Opens metadata database in directory.

---------------------------------------------------------------------------

Name : open_database

Parameters:

dir

directory where the database resides. This is the same place as where the files are stored.

Returns:

pointer to a valid erMedadb object on success, NULL on failure

--------------------------------------------------------------------------

Definition at line 90 of file hello-world/src/db.c.

References ermetadb_global_open(), and ERRORPRINTF.

Referenced by do_example_db_actions().

{
    g_assert(dir != NULL);

    erMetadb db = ermetadb_global_open(dir, FALSE);
    if ( NULL == db) {
        ERRORPRINTF("Could not open database %s", dir );
    } 
    return db;
}

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void pixbuf_draw_rectangle	(	GdkPixbuf *	pixbuf,
		gint	xx,
		gint	yy,
		gint	ww,
		gint	hh,
		gint	color
	)

Draw a rectangle border in a pixbuf.

---------------------------------------------------------------------------

Name : pixbuf_draw_rectangle

Parameters:

	pixbuf	pointer to GdkPixbuf to be converted to BLOB
	xx	x position offset
	yy	y position offset
	ww	width in pixels
	hh	height pixels
	color	RGB color

Returns:

--

--------------------------------------------------------------------------

Definition at line 399 of file hello-world/src/db.c.

References set_pixel_value().

Referenced by do_example_db_actions().

{
    if (pixbuf == NULL)
    {
        return;
    }

    gint w = gdk_pixbuf_get_width (pixbuf);
    gint h = gdk_pixbuf_get_height (pixbuf);

    gint i, j, x, y;
    
    // draw top, buttom line
    for (i = 0; i < 2; ++i)
    {
        if (i == 0)
        {
            y = yy;
        }
        else
        {
            y = yy + hh - 1;
        }

        x = xx;
        for (j = 0; j < ww; ++j)
        {
            if ((x + j) < w && y < h)
                set_pixel_value(pixbuf, x + j, y, color);
        }
    }

    // draw left, right line
    for (i = 0; i < 2; ++i)
    {
        if (i == 0)
        {
            x = xx;
        }
        else
        {
            x = xx + ww -1;
        }

        y = yy;
        for (j = 0; j < hh; ++j)
        {
            if (x < w && (y + j) < h)
            {
                set_pixel_value(pixbuf, x, y + j, color);
            }
        }
    }
}

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gboolean pixbuf_to_blob	(	GdkPixbuf *IN	pixbuf,
		gchar **OUT	buffer,
		gsize *OUT	buf_size
	)

Converts a GdkPixbuf* to a BLOB buffer.

---------------------------------------------------------------------------

Name : pixbuf_to_blob

Parameters:

	pixbuf	pointer to GdkPixbuf to be converted to BLOB
	buffer	buffer in where the data of the BLOB is stored
	buf_size	size of the buffer after conversion

Returns:

FALSE on failure, TRUE on success

--------------------------------------------------------------------------

Referenced by do_example_db_actions().

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gboolean save_file_metadata	(	erMetadb IN	db,
		const gchar *IN	filepath,
		const gchar *IN	filename,
		GString *IN	title,
		GString *IN	author,
		thumbType *IN	small,
		thumbType *IN	medium
	)

Saves the file metadata to database.

---------------------------------------------------------------------------

Name : save_file_metadata

Parameters:

	db	pointer to a valid erMetadb object
	filepath	filepath for which to save metadata
	filename	filename for which to save metadata
	title	pointer to GString to store the title NULL -> title should not be stored
	author	pointer to GString to store the author NULL -> author should not be stored

Returns:

FALSE on failure, TRUE on success

--------------------------------------------------------------------------

Definition at line 248 of file hello-world/src/db.c.

References ER_FAIL, ER_OK, ermetadb_global_change_file(), ERRORPRINTF, FILE_AUTHOR, FILE_TITLE, metadata_table_add_column(), metadata_table_free, metadata_table_new(), metadata_table_set_blob(), metadata_table_set_text(), THUMBNAIL_COLUMNS, THUMBNAIL_MEDIUM, and THUMBNAIL_SMALL.

Referenced by do_example_db_actions().

{
    g_assert(db != NULL);
    g_assert(filename != NULL);

    // create table
    metadata_table *value_table = metadata_table_new();
    g_return_val_if_fail( NULL != value_table, FALSE);

    int value_index = -1;

    int rc = ER_FAIL;
    gboolean save_needed = FALSE;

    // NOTE: This could be optimized; right now all information that is present is
    //       always written to the metadata library, even if nothing has changed
    if (title)
    {
        // set title
        gchar* tmp_title =   g_strdup(title->str);
        // get rid of some special characters
        g_strdelimit(tmp_title, "\t\n\r", ' ');
        // trim the heading and tailing spaces
        g_strstrip(tmp_title);

        metadata_table_add_column(value_table, FILE_TITLE);
        value_index++;
        rc = metadata_table_set_text(value_table, value_index, tmp_title);
        if (rc == ER_OK)
        {
            save_needed = TRUE;
        }
        else
        {
            ERRORPRINTF("Cannot write value %s to table.", tmp_title);
        }
        g_free(tmp_title);
    }

    // set author
    if (author)
    {
        gchar * tmp =   g_strdup(author->str);
        // get rid of some special characters
        g_strdelimit(tmp, "\t\n\r", ' ');
        // trim the heading and tailing spaces
        g_strstrip(tmp);

        metadata_table_add_column(value_table, FILE_AUTHOR);
        value_index++;
        rc = metadata_table_set_text(value_table, value_index, tmp);
        if (rc == ER_OK)
        {
            save_needed = TRUE;
        }
        else
        {
            ERRORPRINTF("Cannot write value %s to table.", tmp);
        }

        g_free(tmp);
    }

    if ( small )
    {
        gchar* blob = (gchar*) small->data;
        gsize  blob_size = small->size;

        // add column according to the size
        metadata_table_add_column(value_table, THUMBNAIL_COLUMNS[THUMBNAIL_SMALL]);
        value_index++;
        rc = metadata_table_set_blob(value_table, value_index, blob, blob_size);
        if (rc== ER_OK)
        {
            save_needed = TRUE;
        }
        else
        {
            ERRORPRINTF("Cannot write thumbnail %s to table.", "small");
        }
    }

    if ( medium )
    {
        gchar* blob = (gchar*) medium->data;
        gsize  blob_size = medium->size;

        // add column according to the size
        metadata_table_add_column(value_table, THUMBNAIL_COLUMNS[THUMBNAIL_MEDIUM]);
        value_index++;
        rc = metadata_table_set_blob(value_table, value_index, blob, blob_size);
        if (rc== ER_OK)
        {
            save_needed = TRUE;
        }
        else
        {
            ERRORPRINTF("Cannot write thumbnail %s to table.", "medium");
        }
    }

    // write values to database
    if (save_needed)
    {
        rc = ermetadb_global_change_file(db, filepath, filename, value_table);
    }
    else
    {
        ERRORPRINTF("No metadata saved, options empty?");
    }

    // clean up
    metadata_table_free(value_table);

    if (rc != ER_OK)  { return FALSE; }
    
    return TRUE;
}

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