images::PagesCache Class Reference

The pages cache can be used to cache ImagePages. More...

#include <images_pages_cache.h>

Public Member Functions
	PagesCache (void)
	~PagesCache (void)
bool	set_memory_limit (const int bytes)
	Reset the size of pages cache.
bool	make_enough_memory (const gint64 length)
bool	add_page (ImagePage *p)
	Add a new page.
ImagePage *	get_page (const size_t idx)
	Get a page.
void	lock (void)
	Lock the whole PagesCache. Notes, Don't call these two functions around APIs of PagesCache. For inside of these APIs, already use lock() and unlock () to guarantee they are thread-safe.
void	unlock (void)
	Unlock the whole PagesCache. Notes, See lock().

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Detailed Description

The pages cache can be used to cache ImagePages.

Definition at line 48 of file images_pages_cache.h.

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Constructor & Destructor Documentation

images::PagesCache::PagesCache

(

void

)

Definition at line 33 of file images_pages_cache.cpp.

: total_length(DEFAULT_MEMORY_LIMIT)
, used_length(0)
, pages()
, cache_mutex(0)
{
    cache_mutex = g_mutex_new();
}

images::PagesCache::~PagesCache

(

void

)

Definition at line 42 of file images_pages_cache.cpp.

{
    g_mutex_lock(cache_mutex);
    clear();
    g_mutex_unlock(cache_mutex);
    g_mutex_free(cache_mutex);
}

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Member Function Documentation

bool images::PagesCache::add_page

(

ImagePage *

p

)

Add a new page.

Definition at line 95 of file images_pages_cache.cpp.

References images::ImagePage::length(), and make_enough_memory().

Referenced by images::ImagesRenderer::add_page().

{
    if (!p) { return false; }

    const int length = p->length();

    // make room in cache, if needed
    make_enough_memory( static_cast<gint64>(length) );

    // insert the new page into cache
    g_mutex_lock(cache_mutex);
    pages[(*p)()] = p;
    used_length += length;
    g_mutex_unlock(cache_mutex);

    return true;
}

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ImagePage * images::PagesCache::get_page

(

const size_t

idx

)

Get a page.

Definition at line 113 of file images_pages_cache.cpp.

Referenced by images::ImagesRenderer::get_page().

{
    g_mutex_lock(cache_mutex);
    
    ImagePage * p = 0;
    PagesIter iter = pages.find(idx);
    if (iter != pages.end())
    {
        p = iter->second;
    }

    g_mutex_unlock(cache_mutex);
    return p;
}

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void images::PagesCache::lock

(

void

)

Lock the whole PagesCache. Notes, Don't call these two functions around APIs of PagesCache. For inside of these APIs, already use lock() and unlock () to guarantee they are thread-safe.

Definition at line 128 of file images_pages_cache.cpp.

Referenced by images::ImagesRenderer::notify_page_ready().

{
    g_mutex_lock(cache_mutex);
}

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bool images::PagesCache::make_enough_memory

(

const gint64

length

)

Remove the old pages to make sure the memory is enough NOTE: length might be less than 0

Definition at line 73 of file images_pages_cache.cpp.

References LOGPRINTF.

Referenced by add_page(), and images::ImagesRenderer::can_render().

{
    bool ok = true;

    g_mutex_lock(cache_mutex);
    LOGPRINTF("used [%d] total [%d] request [%lld]", used_length, total_length, length);
    
    while ( ok && length > static_cast<gint64>(total_length - used_length) )
    {
        if (!remove_page())
        {
            // Remove fails, because:
            // 1. There is no any cached images any more.
            // 2. The image is in use and can't be removed.
            ok = false;
        }
    }

    g_mutex_unlock(cache_mutex);
    return ok;
}

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bool images::PagesCache::set_memory_limit

(

const int

bytes

)

Reset the size of pages cache.

Definition at line 50 of file images_pages_cache.cpp.

Referenced by images::ImagesRenderer::set_memory_limit().

{
    g_mutex_lock(cache_mutex);

    if (total_length > static_cast<unsigned int>(bytes))
    {
        //remove the redundant pages
        while (used_length > static_cast<unsigned int>(bytes))
        {
            if (!remove_page())
            {
                g_mutex_unlock(cache_mutex);
                return false;
            }
        }
    }

    total_length = static_cast<unsigned int>(bytes);
    
    g_mutex_unlock(cache_mutex);
    return true;
}

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void images::PagesCache::unlock

(

void

)

Unlock the whole PagesCache. Notes, See lock().

Definition at line 133 of file images_pages_cache.cpp.

Referenced by images::ImagesRenderer::notify_page_ready().

{
    g_mutex_unlock(cache_mutex);
}

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The documentation for this class was generated from the following files:

• images_pages_cache.h
• images_pages_cache.cpp