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/*

 * Copyright 2011 John-Mark Bell 

 *

 * This file is part of NetSurf, http://www.netsurf-browser.org/

 *

 * NetSurf is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 of the License.

 *

 * NetSurf is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see .

 */

/** \file

 * The image content handler intermediate image cache.

 *

 * This cache allows netsurf to use a generic intermediate bitmap

 * format without keeping the

 * intermediate representation in memory.

 *

 * The bitmap structure is opaque to the rest of netsurf and is

 * controlled by the platform-specific code (see image/bitmap.h for

 * detials). All image content handlers convert into this format and

 * pass it to the plot functions for display,

 *

 * This cache maintains a link between the underlying original content

 * and the intermediate representation. It is intended to be flexable

 * and either manage the bitmap plotting completely or give the image

 * content handler complete control.

 */

#ifndef NETSURF_IMAGE_IMAGE_CACHE_H_

#define NETSURF_IMAGE_IMAGE_CACHE_H_

#include "utils/errors.h"

#include "desktop/plotters.h"

#include "image/bitmap.h"

typedef struct bitmap * (image_cache_convert_fn) (struct content *content);

struct image_cache_parameters {

	/** How frequently the background cache clean process is run (ms) */

	unsigned int bg_clean_time;

	/** The target upper bound for the image cache size */

	size_t limit;

	/** The hysteresis allowed round the target size */

	size_t hysteresis;

	/** The speculative conversion "small" size */

	size_t speculative_small;

};

/** Initialise the image cache

 *

 * @param image_cache_parameters The control parameters for the image cache

 */

nserror image_cache_init(const struct image_cache_parameters *image_cache_parameters);

nserror image_cache_fini(void);

/** adds an image content to be cached.

 *

 * @param content The content handle used as a key

 * @param bitmap A bitmap representing the already converted content or NULL.

 * @param convert A function pointer to convert the content into a bitmap or NULL.

 * @return A netsurf error code.

 */

nserror image_cache_add(struct content *content,

			struct bitmap *bitmap,

			image_cache_convert_fn *convert);

nserror image_cache_remove(struct content *content);

/** Obtain a bitmap from a content converting from source if neccessary. */

struct bitmap *image_cache_get_bitmap(const struct content *c);

/** Obtain a bitmap from a content with no conversion */

struct bitmap *image_cache_find_bitmap(struct content *c);

/** Decide if a content should be speculatively converted.

 *

 * This allows for image content handlers to ask the cache if a bitmap

 * should be generated before it is added to the cache. This is the

 * same decision logic used to decide to perform an immediate

 * conversion when a content is initially added to the cache.

 *

 * @param c The content to be considered.

 * @return true if a speculative conversion is desired false otehrwise.

 */

bool image_cache_speculate(struct content *c);

/**

 * Fill a buffer with information about a cache entry using a format.

 *

 * The format string is copied into the output buffer with the

 * following replaced:

 * %e - The entry number

 * %k - The content key

 * %r - The number of redraws of this bitmap

 * %c - The number of times this bitmap has been converted

 * %s - The size of the current bitmap allocation

 *

 * \param string  The buffer in which to place the results.

 * \param size    The size of the string buffer.

 * \param entryn  The opaque entry number.

 * \param fmt     The format string.

 * \return The number of bytes written to \a string or -1 on error

 */

int image_cache_snentryf(char *string, size_t size, unsigned int entryn,

			 const char *fmt);

/**

 * Fill a buffer with information about the image cache using a format.

 *

 * The format string is copied into the output buffer with the

 * following replaced:

 *

 * a Configured cache limit size

 * b Configured cache hysteresis size

 * c Current caches total consumed size

 * d Number of images currently in the cache

 * e The age of the cache

 * f The largest amount of space the cache has occupied since initialisation

 * g The number of objetcs when the cache was at its largest

 * h The largest number of images in the cache since initialisation

 * i The size of the cache when the largest number of objects occoured

 * j The total number of read operations performed on the cache

 * k The total number of read operations satisfied from the cache without

 *     conversion.

 * l The total number of read operations satisfied from the cache which

 *     required a conversion.

 * m The total number of read operations which could not be sucessfully

 *     returned. ie. not available in cache and conversion failed.

 * n The total size  of read operations performed on the cache

 * o The total size of read operations satisfied from the cache without

 *     conversion.

 * q The total size of read operations satisfied from the cache which

 *     required a conversion.

 * r The total size of read operations which could not be sucessfully

 *     returned. ie. not available in cache and conversion failed.

 * s The number of images which were placed in the cache but never read.

 * t The number of images that were converted on insertion into teh cache which were subsequently never used.

 * u The number of times an image was converted after the first

 * v The number of images that had extra conversions performed.

 * w Size of the image that was converted (read missed cache) highest number

 *     of times.

 * x The number of times the image that was converted (read missed cache)

 *     highest number of times.

 *

 * format modifiers:

 * A p before the value modifies the replacement to be a percentage.

 *

 *

 * \param string  The buffer in which to place the results.

 * \param size    The size of the string buffer.

 * \param fmt     The format string.

 * \return The number of bytes written to \a string or -1 on error

 */

int image_cache_snsummaryf(char *string, size_t size, const char *fmt);

/********* Image content handler generic cache callbacks ************/

/** Generic content redraw callback

 *

 * May be used by image content handlers as their redraw

 * callback. Performs all neccissary cache lookups and conversions and

 * calls the bitmap plot function in the redraw context.

 */

bool image_cache_redraw(struct content *c,

			struct content_redraw_data *data,

			const struct rect *clip,

			const struct redraw_context *ctx);

void image_cache_destroy(struct content *c);

void *image_cache_get_internal(const struct content *c, void *context);

content_type image_cache_content_type(void);

#endif