(C) An X-Ryl669 project 2007
This document describes Unlimited Zooming Interface source code. UZI stands for Unlimited Zooming Interface, and source code license is
#include <CacheEngine.hpp>
Every time a document is loaded, it is a good idea to declare it on the cache. The holder indexes the document address, and store an internal reference on the document content. Next time a document is requested, the cache will find the content in O(log N) time, avoiding downloading it again.
Typical usage is to attach a RequiredFetcherImplementation to the holder, so the holder can decide when to download a document.
Usually, the cache holder groups items in ItemGroup, from a same "root" URL. It's possible to query the group fetching advancement, in order to update a progress bar, or something like this.
The holder is monitoring the memory it uses, and as soon as the cached memory overcome a given limit, the holder will remove the oldest element from the cache until the limit is reached again (plus a given 10% margin and VAT).
Public Types | |
| typedef Container::PlainOldData< volatile Item * >::Array | ItemGroup |
| An item group declaration. | |
| typedef Container::NotConstructible< ItemGroup >::ChainedList | ItemGroupList |
| The list of item groups declaration. | |
Public Member Functions | |
| ItemGroup * | addGroupFromRoot (const Strings::FastString &URL, void *opaque) |
| Add a group to the cache with the given "root" URL. | |
| bool | addItemToGroup (const Strings::FastString &URL, ItemGroup *group) |
| Add an item to a group from the given URL. | |
| bool | emptyCache (const uint32 size) |
| Empty the cache to ensure the given amount of free bytes. | |
| const bool | entireGroupReady (const ItemGroup *group) |
| Check if a group is ready for presentation. | |
| ItemGroup * | findGroupFromItem (volatile Item *item) |
| Find a group containing the given item. | |
| volatile Item * | findItemFromURL (const Strings::FastString &URL) |
| Find an item from its URL. | |
| ItemGroup * | findRoot (const Strings::FastString &URL) |
| Find a root from a given URL. | |
| const uint32 | getFetchingAdvancement (const ItemGroup *group, bool booleanResult=false) |
| Check the advancement of a group fetching. | |
| const bool | groupFetchingError (const ItemGroup *group) |
| Check if there was a fatal error while fetching a group. | |
| Holder (RequiredFetcherImplementation &_fetcher, const uint32 maxSize=33554432) | |
| The only constructor. | |
| virtual | ~Holder () |
| The destructor. | |
| typedef Container::PlainOldData<volatile Item *>::Array Cache::Holder::ItemGroup |
An item group declaration.
| typedef Container::NotConstructible<ItemGroup>::ChainedList Cache::Holder::ItemGroupList |
The list of item groups declaration.
| Cache::Holder::Holder | ( | RequiredFetcherImplementation & | _fetcher, | |
| const uint32 | maxSize = 33554432 | |||
| ) | [inline] |
The only constructor.
This constructor sets the fetcher, and the maximum allowed size before pruning the oldest element from cache
| _fetcher | A reference on a fecther implementation | |
| maxSize | The maximum allowed size in bytes (default is 32MB) |
| virtual Cache::Holder::~Holder | ( | ) | [inline, virtual] |
The destructor.
| ItemGroup* Cache::Holder::addGroupFromRoot | ( | const Strings::FastString & | URL, | |
| void * | opaque | |||
| ) | [inline] |
Add a group to the cache with the given "root" URL.
The "root" URL is fetched.
| URL | The URL to fetch. URL is UTF8 encoded | |
| opaque | An opaque object that could be used to pass any structure from the cache to the fetcher |
| bool Cache::Holder::addItemToGroup | ( | const Strings::FastString & | URL, | |
| ItemGroup * | group | |||
| ) | [inline] |
Add an item to a group from the given URL.
The item URL is fetched.
| URL | The URL to fetch. URL is UTF8 encoded | |
| group | The group to add this item to. |
| bool Cache::Holder::emptyCache | ( | const uint32 | size | ) | [inline] |
Empty the cache to ensure the given amount of free bytes.
| size | The free size to get when exiting |
| const bool Cache::Holder::entireGroupReady | ( | const ItemGroup * | group | ) | [inline] |
Check if a group is ready for presentation.
This method is very similar to getFetchingAdvancement, expect the return is boolean. This call is non blocking, as long as the fetcher's isItemFetched is not
| group | The ItemGroup pointer to inspect |
Find a group containing the given item.
| item | The item pointer to look for |
| volatile Item* Cache::Holder::findItemFromURL | ( | const Strings::FastString & | URL | ) | [inline] |
Find an item from its URL.
| URL | The URL to look for. URL is UTF8 encoded |
| ItemGroup* Cache::Holder::findRoot | ( | const Strings::FastString & | URL | ) | [inline] |
Find a root from a given URL.
| URL | The URL to fetch. URL is UTF8 encoded |
| const uint32 Cache::Holder::getFetchingAdvancement | ( | const ItemGroup * | group, | |
| bool | booleanResult = false | |||
| ) | [inline] |
Check the advancement of a group fetching.
This call is non blocking, as long as the fetcher's isItemFetched is not
| group | The ItemGroup pointer to inspect | |
| booleanResult | Does the result be 0 or 100 only, or can it spread over the whole range (whole range by default). |
| const bool Cache::Holder::groupFetchingError | ( | const ItemGroup * | group | ) | [inline] |
Check if there was a fatal error while fetching a group.
This can happen if root-level items have failed to fetch
| group | The ItemGroup pointer to inspect |