haiku-beta6/src/kits/tracker/IconCache.h

/*
Open Tracker License

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the Software without restriction, including without limitation the rights to
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*/

//	Icon cache is used for drawing node icons; it caches icons
//	and reuses them for successive draws

#ifndef __NU_ICON_CACHE__
#define __NU_ICON_CACHE__

#include <Bitmap.h>
#include <Mime.h>
#include <String.h>

#include "AutoLock.h"
#include "ObjectList.h"
#include "OpenHashTable.h"
#include "Utilities.h"

// Icon cache splits icons into two caches - the shared cache, likely to get the
// most hits and the node cache. Every icon that is found in a mime based
// structure goes into the shared cache, only files that have their own private
// icon use the node cache;
// Entries are only deleted from the shared cache if an icon for a mime type changes,
// this makes async icon drawing easier. Node cache deletes it's entries whenever a
// file gets deleted.

// if a view ever uses the cache to draw in async mode, it needs to call
// it when it is being destroyed

namespace BPrivate {

class Model;
class ModelNodeLazyOpener;
class LazyBitmapAllocator;
class SharedIconCache;
class SharedCacheEntry;

enum IconDrawMode {
	// Different states of icon drawing
	kSelected 					= 0x01,
	kNotFocused					= 0x02,		// Tracker window
	kOpen						= 0x04,		// open folder, trash
	kNotEmpty					= 0x08,		// full trash
	kDisabled					= 0x10,		// inactive nav menu entry
	kActive						= 0x20,		// active home dir, boot volume
	kLink						= 0x40,		// symbolic link
	kTrackerSpecialized			= 0x80,

	// some common combinations
	kNormalIcon						= 0,
	kSelectedIcon					= kSelected,
	kSelectedInBackgroundIcon		= kSelected | kNotFocused,
	kOpenIcon						= kOpen,
	kOpenSelectedIcon				= kSelected | kOpen,
	kOpenSelectedInBackgroundIcon	= kSelected | kNotFocused | kOpen,
	kFullIcon						= kNotEmpty,
	kFullSelectedIcon				= kNotEmpty | kOpen,
	kDimmedIcon
};

#define NORMAL_ICON_ONLY kNormalIcon
	// replace use of these defines with mode once the respective getters
	// can get non-plain icons


// Where did an icon come from
enum IconSource {
	kUnknownSource,
	kUnknownNotFromNode,	// icon origin not known but determined not to be from
							// the node itself
	kTrackerDefault,		// file has no type, Tracker provides generic, folder,
							// symlink or app
	kTrackerSupplied,		// home directory, boot volume, trash, etc.
	kMetaMime,				// from BMimeType
	kPreferredAppForType,	// have a preferred application for a type, has an icon
	kPreferredAppForNode,	// have a preferred application for this node,
							// has an icon
	kVolume,
	kNode
};

class IconCacheEntry {
	// aliased entries don't own their icons, just point
	// to some other entry that does
	
	// This is used for icons that are defined by a preferred app for
	// a metamime, types that do not have an icon get to point to
	// generic, etc.
	
public:
	IconCacheEntry();
	~IconCacheEntry();
	
	void SetAliasFor(const SharedIconCache *, const SharedCacheEntry *);
	static IconCacheEntry *ResolveIfAlias(const SharedIconCache *, IconCacheEntry *);
	IconCacheEntry *ResolveIfAlias(const SharedIconCache *);
	
	void SetIcon(BBitmap *bitmap, IconDrawMode mode, icon_size size,
		bool create = false);
	
	bool HaveIconBitmap(IconDrawMode mode, icon_size size) const;
	bool CanConstructBitmap(IconDrawMode mode, icon_size size) const;
	static bool AlternateModeForIconConstructing(IconDrawMode requestedMode,
		IconDrawMode &alternate, icon_size size);
	BBitmap *ConstructBitmap(BBitmap *constructFrom, IconDrawMode requestedMode,
		IconDrawMode constructFromMode, icon_size size,
		LazyBitmapAllocator *);
	BBitmap *ConstructBitmap(IconDrawMode requestedMode, icon_size size,
		LazyBitmapAllocator *);
		// same as above, always uses normal icon as source	

	bool IconHitTest(BPoint, IconDrawMode, icon_size) const;
		// given a point, returns true if a non-transparent pixel was hit

	void RetireIcons(BObjectList<BBitmap> *retiredBitmapList);
		// can't just delete icons, they may be still drawing
		// async; instead, put them on the retired list and
		// only delete the list if it grows too much, way after
		// the icon finishes drawing
		// 
		// This could fail if we retire a lot of icons (10 * 1024)
		// while we are drawing them, shouldn't be a practical problem

protected:

	BBitmap *IconForMode(IconDrawMode mode, icon_size size) const;
	void SetIconForMode(BBitmap *bitmap, IconDrawMode mode, icon_size size);

	// list of most common icons
	BBitmap *fLargeIcon;
	BBitmap *fMiniIcon;
	BBitmap *fHilitedLargeIcon;
	BBitmap *fHilitedMiniIcon;
	int32 fAliasForIndex;
	
	// list of other icon kinds would be added here
	
	friend class SharedIconCache;
	friend class NodeIconCache;
};

class SimpleIconCache {
public:
	SimpleIconCache(const char *);
	virtual ~SimpleIconCache() {}

	virtual void Draw(IconCacheEntry *, BView *, BPoint, IconDrawMode mode,
		icon_size size, bool async = false) = 0;
	virtual void Draw(IconCacheEntry *, BView *, BPoint , IconDrawMode ,
		icon_size , void (*)(BView *, BPoint, BBitmap *, void *), void * = NULL) = 0;

	bool Lock();
	void Unlock();
	bool IsLocked() const;
	
private:
	Benaphore fLock;
};

class SharedCacheEntry : public IconCacheEntry {
public:
	SharedCacheEntry();
	SharedCacheEntry(const char *fileType, const char *appSignature = 0);

	void Draw(BView *, BPoint, IconDrawMode mode, icon_size size,
		bool async = false);

	void Draw(BView *, BPoint , IconDrawMode , icon_size ,
		void (*)(BView *, BPoint, BBitmap *, void *), void * = NULL);

	const char *FileType() const;
	const char *AppSignature() const;
	
	// hash table support
	uint32 Hash() const;
	static uint32 Hash(const char *fileType, const char *appSignature = 0);
	bool operator==(const SharedCacheEntry &) const;
	void SetTo(const char *fileType, const char *appSignature = 0);

	int32 fNext;
private:
	BString fFileType;
	BString fAppSignature;

	friend class SharedIconCache;
};

class SharedCacheEntryArray : public OpenHashElementArray<SharedCacheEntry> {
	// SharedIconCache stores all it's elements in this array
public:
	SharedCacheEntryArray(int32 initialSize);
	SharedCacheEntry *Add();
};

class SharedIconCache : public SimpleIconCache {
	// SharedIconCache is used for icons that come from the mime database
public:
	SharedIconCache();

	virtual void Draw(IconCacheEntry *, BView *, BPoint, IconDrawMode mode,
		icon_size size, bool async = false);
	virtual void Draw(IconCacheEntry *, BView *, BPoint , IconDrawMode ,
		icon_size , void (*)(BView *, BPoint, BBitmap *, void *), void * = NULL);

	SharedCacheEntry *FindItem(const char *fileType, const char *appSignature = 0)
		const;
	SharedCacheEntry *AddItem(const char *fileType, const char *appSignature = 0);
	SharedCacheEntry *AddItem(SharedCacheEntry **outstandingEntry, const char *fileType,
		const char *appSignature = 0);
		// same as previous AddItem, updates the pointer to outstandingEntry, because
		// adding to the hash table makes any pending pointer invalid
	void IconChanged(SharedCacheEntry *);

	void SetAliasFor(IconCacheEntry *alias, const SharedCacheEntry *original) const;
	IconCacheEntry *ResolveIfAlias(IconCacheEntry *entry) const;
	int32 EntryIndex(const SharedCacheEntry *entry) const;

	void RemoveAliasesTo(int32 index);

private:
	OpenHashTable<SharedCacheEntry, SharedCacheEntryArray> fHashTable;
	SharedCacheEntryArray fElementArray;
	BObjectList<BBitmap> fRetiredBitmaps;
		// icons are drawn asynchronously, can't just delete them
		// right away, instead have to place them onto the retired bitmap list
		// and wait for the next sync to delete them
};

class NodeCacheEntry : public IconCacheEntry {
public:
	NodeCacheEntry(bool permanent = false);
	NodeCacheEntry(const node_ref *, bool permanent = false);
	void Draw(BView *, BPoint, IconDrawMode mode, icon_size size,
		bool async = false);
	
	void Draw(BView *, BPoint , IconDrawMode , icon_size ,
		void (*)(BView *, BPoint, BBitmap *, void *), void * = NULL);

	const node_ref *Node() const;
	
	uint32 Hash() const;
	static uint32 Hash(const node_ref *);
	bool operator==(const NodeCacheEntry &) const;
	void SetTo(const node_ref *);
	void MakePermanent();
	bool Permanent() const;
	
	int32 fNext;
private:
	node_ref fRef;
	bool fPermanent;
		// special cache entry that has to be deleted explicitly

	friend class NodeIconCache;
};

class NodeCacheEntryArray : public OpenHashElementArray<NodeCacheEntry> {
	// NodeIconCache stores all it's elements in this array
public:
	NodeCacheEntryArray(int32 initialSize);
	NodeCacheEntry *Add();
};

class NodeIconCache : public SimpleIconCache {
	// NodeIconCache is used for nodes that define their own icons
public:
	NodeIconCache();

	virtual void Draw(IconCacheEntry *, BView *, BPoint, IconDrawMode ,
		icon_size , bool async = false);

	virtual void Draw(IconCacheEntry *, BView *, BPoint , IconDrawMode ,
		icon_size , void (*)(BView *, BPoint, BBitmap *, void *), void * = 0);

	NodeCacheEntry *FindItem(const node_ref *) const;
	NodeCacheEntry *AddItem(const node_ref *, bool permanent = false);
	NodeCacheEntry *AddItem(NodeCacheEntry **outstandingEntry, const node_ref *);
		// same as previous AddItem, updates the pointer to outstandingEntry, because
		// adding to the hash table makes any pending pointer invalid
	void Deleting(const node_ref *);
		// model for this node is getting deleted (not necessarily the node itself)
	void Removing(const node_ref *);
		// used by permanent NodeIconCache entries, when an entry gets deleted
	void Deleting(const BView *);
	void IconChanged(const Model *);


	void RemoveAliasesTo(int32 index);

private:
	OpenHashTable<NodeCacheEntry, NodeCacheEntryArray> fHashTable;
	NodeCacheEntryArray fElementArray;
};

const int32 kColorTransformTableSize = 256;

class IconCache {
public:
	IconCache();
	
	void Draw(Model *, BView *, BPoint where, IconDrawMode mode,
		icon_size size, bool async = false);
		// draw an icon for a model, load the icon from the appropriate
		// location if not cached already

	void SyncDraw(Model *, BView *, BPoint , IconDrawMode ,
		icon_size , void (*)(BView *, BPoint, BBitmap *, void *), 
		void *passThruState = 0);
		// draw an icon for a model, load the icon from the appropriate
		// location if not cached already; only works for sync draws,
		// once the call returns, the bitmap may be deleted

	// preload calls used to ensure successive cache hit for the respective
	// icon, used for common tracker types, etc; Not calling these should only
	// cause a slowdown
	void Preload(Model *, IconDrawMode mode, icon_size size, bool permanent = false);
	status_t Preload(const char *mimeType, IconDrawMode mode, icon_size size);

	void Deleting(const Model *);
		// hook to manage unloading icons for nodes that are going away 
	void Removing(const Model *model);
		// used by permanent NodeIconCache entries, when an entry gets
		// deleted
	void Deleting(const BView *);
		// hook to manage deleting draw view caches for views that are
		// going away
	
	// icon changed calls, used when a node or a file type has an icon changed
	// the icons for the node/file type will be flushed and re-cached during
	// the next draw
	void IconChanged(Model *);
	void IconChanged(const char *mimeType, const char *appSignature);
	
	bool IsIconFrom(const Model *, const char *mimeType,
		const char *appSignature) const;
		// called when metamime database changed to figure out which models
		// to redraw

	bool IconHitTest(BPoint, const Model *, IconDrawMode , icon_size );

	// utility calls for building specialized icons
	BBitmap *MakeSelectedIcon(const BBitmap *normal, icon_size,
		LazyBitmapAllocator *);
	
	
	static bool NeedsDeletionNotification(IconSource);

	static IconCache *sIconCache;

private:
	
	// shared calls
	IconCacheEntry *Preload(AutoLock<SimpleIconCache> *nodeCache,
		AutoLock<SimpleIconCache> *sharedCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconDrawMode mode, icon_size size, bool permanent);
		// preload uses lazy locking, returning the cache we decided
		// to use to get the icon
		// <resultingLockedCache> may be null if we don't care

	// shared mime-based icon retrieval calls
	IconCacheEntry *GetIconForPreferredApp(const char *mimeTypeSignature,
		const char *preferredApp, IconDrawMode mode, icon_size size,
		 LazyBitmapAllocator *, IconCacheEntry *);
	IconCacheEntry *GetIconFromFileTypes(ModelNodeLazyOpener *, IconSource &source,
		IconDrawMode mode, icon_size size, LazyBitmapAllocator *,
		IconCacheEntry *);
	IconCacheEntry *GetIconFromMetaMime(const char *fileType, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *,
		IconCacheEntry *);
	IconCacheEntry *GetVolumeIcon(AutoLock<SimpleIconCache> *nodeCache,
		AutoLock<SimpleIconCache> *sharedCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconSource &, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *);
	IconCacheEntry *GetRootIcon(AutoLock<SimpleIconCache> *nodeCache,
		AutoLock<SimpleIconCache> *sharedCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconSource &, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *);
	IconCacheEntry *GetWellKnownIcon(AutoLock<SimpleIconCache> *nodeCache,
		AutoLock<SimpleIconCache> *sharedCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconSource &, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *);
	IconCacheEntry *GetNodeIcon(ModelNodeLazyOpener *,
		AutoLock<SimpleIconCache> *nodeCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconSource &, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *, IconCacheEntry *, bool permanent);
	IconCacheEntry *GetGenericIcon(AutoLock<SimpleIconCache> *sharedCache,
		AutoLock<SimpleIconCache> **resultingLockedCache,
		Model *, IconSource &, IconDrawMode mode,
		icon_size size, LazyBitmapAllocator *, IconCacheEntry *);
	IconCacheEntry *GetFallbackIcon(AutoLock<SimpleIconCache> *sharedCacheLocker,
		AutoLock<SimpleIconCache> **resultingOpenCache,
		Model *model, IconDrawMode mode, icon_size size,
		LazyBitmapAllocator *lazyBitmap, IconCacheEntry *entry);

	BBitmap *MakeTransformedIcon(const BBitmap *, icon_size,
		int32 colorTransformTable [], LazyBitmapAllocator *);

	NodeIconCache fNodeCache;
	SharedIconCache fSharedCache;

	void InitHiliteTable();

	int32 fHiliteTable[kColorTransformTableSize];
	bool fInitHiliteTable;
		// on if we still need to initialize the hilite table
};


class LazyBitmapAllocator {
// Utility class used when we aren't sure that we will keep a bitmap,
// need a bitmap or be able to construct it properly
public:
	LazyBitmapAllocator(icon_size size,
						color_space colorSpace = kDefaultIconDepth,
		bool preallocate = false);
	~LazyBitmapAllocator();

	BBitmap *Get();
	BBitmap *Adopt();

private:
	BBitmap *fBitmap;
	icon_size fSize;
	color_space fColorSpace;
};

// nothing but inlines after here

inline const char *
SharedCacheEntry::FileType() const
{
	return fFileType.String();
}

inline const char *
SharedCacheEntry::AppSignature() const
{
	return fAppSignature.String();
}

inline bool 
IconCache::NeedsDeletionNotification(IconSource from)
{
	return from == kNode;
}

inline IconCacheEntry *
SharedIconCache::ResolveIfAlias(IconCacheEntry *entry) const
{
	if (entry->fAliasForIndex < 0)
		return entry;
	
	return fHashTable.ElementAt(entry->fAliasForIndex);
}

inline int32 
SharedIconCache::EntryIndex(const SharedCacheEntry *entry) const
{
	return fHashTable.ElementIndex(entry);
}

} // namespace BPrivate

using namespace BPrivate;

#endif