1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkEvent_DEFINED
9#define SkEvent_DEFINED
10
11#include "SkDOM.h"
12#include "SkMetaData.h"
13#include "SkString.h"
14
15/** Unique 32bit id used to identify an instance of SkEventSink. When events are
16    posted, they are posted to a specific sinkID. When it is time to dispatch the
17    event, the sinkID is used to find the specific SkEventSink object. If it is found,
18    its doEvent() method is called with the event.
19*/
20typedef uint32_t SkEventSinkID;
21
22/**
23 *  \class SkEvent
24 *
25 *  When an event is dispatched from the event queue, it is either sent to
26 *  the eventsink matching the target ID (if not 0), or the target proc is
27 *  called (if not NULL).
28 */
29class SkEvent {
30public:
31    /**
32     *  Function pointer that takes an event, returns true if it "handled" it.
33     */
34    typedef bool (*Proc)(const SkEvent& evt);
35
36    SkEvent();
37    explicit SkEvent(const SkString& type, SkEventSinkID = 0);
38    explicit SkEvent(const char type[], SkEventSinkID = 0);
39    SkEvent(const SkEvent& src);
40    ~SkEvent();
41
42    /** Copy the event's type into the specified SkString parameter */
43    void getType(SkString* str) const;
44
45    /** Returns true if the event's type matches exactly the specified type (case sensitive) */
46    bool isType(const SkString& str) const;
47
48    /** Returns true if the event's type matches exactly the specified type (case sensitive) */
49    bool isType(const char type[], size_t len = 0) const;
50
51    /**
52     *  Set the event's type to the specified string.
53     */
54    void setType(const SkString&);
55
56    /**
57     *  Set the event's type to the specified string.
58     */
59    void setType(const char type[], size_t len = 0);
60
61    /**
62     *  Return the target ID, or 0 if there is none.
63     *
64     *  When an event is dispatched from the event queue, it is either sent to
65     *  the eventsink matching the targetID (if not 0), or the target proc is
66     *  called (if not NULL).
67     */
68    SkEventSinkID getTargetID() const { return fTargetID; }
69
70    /**
71     *  Set the target ID for this event. 0 means none. Calling this will
72     *  automatically clear the targetProc to null.
73     *
74     *  When an event is dispatched from the event queue, it is either sent to
75     *  the eventsink matching the targetID (if not 0), or the target proc is
76     *  called (if not NULL).
77     */
78    SkEvent* setTargetID(SkEventSinkID targetID) {
79        fTargetProc = NULL;
80        fTargetID = targetID;
81        return this;
82    }
83
84    /**
85     *  Return the target proc, or NULL if it has none.
86     *
87     *  When an event is dispatched from the event queue, it is either sent to
88     *  the eventsink matching the targetID (if not 0), or the target proc is
89     *  called (if not NULL).
90     */
91    Proc getTargetProc() const { return fTargetProc; }
92
93    /**
94     *  Set the target ID for this event. NULL means none. Calling this will
95     *  automatically clear the targetID to 0.
96     *
97     *  When an event is dispatched from the event queue, it is either sent to
98     *  the eventsink matching the targetID (if not 0), or the target proc is
99     *  called (if not NULL).
100     */
101    SkEvent* setTargetProc(Proc proc) {
102        fTargetID = 0;
103        fTargetProc = proc;
104        return this;
105    }
106
107    /**
108     *  Return the event's unnamed 32bit field. Default value is 0
109     */
110    uint32_t getFast32() const { return f32; }
111
112    /**
113     *  Set the event's unnamed 32bit field.
114     */
115    void setFast32(uint32_t x) { f32 = x; }
116
117    /** Return true if the event contains the named 32bit field, and return the field
118        in value (if value is non-null). If there is no matching named field, return false
119        and ignore the value parameter.
120    */
121    bool findS32(const char name[], int32_t* value = NULL) const { return fMeta.findS32(name, value); }
122    /** Return true if the event contains the named SkScalar field, and return the field
123        in value (if value is non-null). If there is no matching named field, return false
124        and ignore the value parameter.
125    */
126    bool findScalar(const char name[], SkScalar* value = NULL) const { return fMeta.findScalar(name, value); }
127    /** Return true if the event contains the named SkScalar field, and return the fields
128        in value[] (if value is non-null), and return the number of SkScalars in count (if count is non-null).
129        If there is no matching named field, return false and ignore the value and count parameters.
130    */
131    const SkScalar* findScalars(const char name[], int* count, SkScalar values[] = NULL) const { return fMeta.findScalars(name, count, values); }
132    /** Return the value of the named string field, or if no matching named field exists, return null.
133    */
134    const char* findString(const char name[]) const { return fMeta.findString(name); }
135    /** Return true if the event contains the named pointer field, and return the field
136        in value (if value is non-null). If there is no matching named field, return false
137        and ignore the value parameter.
138    */
139    bool findPtr(const char name[], void** value) const { return fMeta.findPtr(name, value); }
140    bool findBool(const char name[], bool* value) const { return fMeta.findBool(name, value); }
141    const void* findData(const char name[], size_t* byteCount = NULL) const {
142        return fMeta.findData(name, byteCount);
143    }
144
145    /** Returns true if ethe event contains the named 32bit field, and if it equals the specified value */
146    bool hasS32(const char name[], int32_t value) const { return fMeta.hasS32(name, value); }
147    /** Returns true if ethe event contains the named SkScalar field, and if it equals the specified value */
148    bool hasScalar(const char name[], SkScalar value) const { return fMeta.hasScalar(name, value); }
149    /** Returns true if ethe event contains the named string field, and if it equals (using strcmp) the specified value */
150    bool hasString(const char name[], const char value[]) const { return fMeta.hasString(name, value); }
151    /** Returns true if ethe event contains the named pointer field, and if it equals the specified value */
152    bool hasPtr(const char name[], void* value) const { return fMeta.hasPtr(name, value); }
153    bool hasBool(const char name[], bool value) const { return fMeta.hasBool(name, value); }
154    bool hasData(const char name[], const void* data, size_t byteCount) const {
155        return fMeta.hasData(name, data, byteCount);
156    }
157
158    /** Add/replace the named 32bit field to the event. In XML use the subelement <data name=... s32=... /> */
159    void setS32(const char name[], int32_t value) { fMeta.setS32(name, value); }
160    /** Add/replace the named SkScalar field to the event. In XML use the subelement <data name=... scalar=... /> */
161    void setScalar(const char name[], SkScalar value) { fMeta.setScalar(name, value); }
162    /** Add/replace the named SkScalar[] field to the event. */
163    SkScalar* setScalars(const char name[], int count, const SkScalar values[] = NULL) { return fMeta.setScalars(name, count, values); }
164    /** Add/replace the named string field to the event. In XML use the subelement <data name=... string=... */
165    void setString(const char name[], const SkString& value) { fMeta.setString(name, value.c_str()); }
166    /** Add/replace the named string field to the event. In XML use the subelement <data name=... string=... */
167    void setString(const char name[], const char value[]) { fMeta.setString(name, value); }
168    /** Add/replace the named pointer field to the event. There is no XML equivalent for this call */
169    void setPtr(const char name[], void* value) { fMeta.setPtr(name, value); }
170    void setBool(const char name[], bool value) { fMeta.setBool(name, value); }
171    void setData(const char name[], const void* data, size_t byteCount) {
172        fMeta.setData(name, data, byteCount);
173    }
174
175    /** Return the underlying metadata object */
176    SkMetaData& getMetaData() { return fMeta; }
177    /** Return the underlying metadata object */
178    const SkMetaData& getMetaData() const { return fMeta; }
179
180    /** Call this to initialize the event from the specified XML node */
181    void inflate(const SkDOM&, const SkDOM::Node*);
182
183    SkDEBUGCODE(void dump(const char title[] = NULL);)
184
185    ///////////////////////////////////////////////////////////////////////////
186
187    /**
188     *  Post to the event queue using the event's targetID or target-proc.
189     *
190     *  The event must be dynamically allocated, as ownership is transferred to
191     *  the event queue. It cannot be allocated on the stack or in a global.
192     */
193    void post() {
194        return this->postDelay(0);
195    }
196
197    /**
198     *  Post to the event queue using the event's targetID or target-proc and
199     *  the specifed millisecond delay.
200     *
201     *  The event must be dynamically allocated, as ownership is transferred to
202     *  the event queue. It cannot be allocated on the stack or in a global.
203     */
204    void postDelay(SkMSec delay);
205
206    /**
207     *  Post to the event queue using the event's targetID or target-proc.
208     *  The event will be delivered no sooner than the specified millisecond
209     *  time, as measured by SkTime::GetMSecs().
210     *
211     *  The event must be dynamically allocated, as ownership is transferred to
212     *  the event queue. It cannot be allocated on the stack or in a global.
213     */
214    void postTime(SkMSec time);
215
216    ///////////////////////////////////////////////
217    /** Porting layer must call these functions **/
218    ///////////////////////////////////////////////
219
220    /** Global initialization function for the SkEvent system. Should be called exactly
221        once before any other event method is called, and should be called after the
222        call to SkGraphics::Init().
223    */
224    static void Init();
225    /** Global cleanup function for the SkEvent system. Should be called exactly once after
226        all event methods have been called.
227    */
228    static void Term();
229
230    /** Call this to process one event from the queue. If it returns true, there are more events
231        to process.
232    */
233    static bool ProcessEvent();
234    /** Call this whenever the requested timer has expired (requested by a call to SetQueueTimer).
235        It will post any delayed events whose time as "expired" onto the event queue.
236        It may also call SignalQueueTimer() and SignalNonEmptyQueue().
237    */
238    static void ServiceQueueTimer();
239
240    /** Return the number of queued events. note that this value may be obsolete
241        upon return, since another thread may have called ProcessEvent() or
242        Post() after the count was made.
243     */
244    static int CountEventsOnQueue();
245
246    ////////////////////////////////////////////////////
247    /** Porting layer must implement these functions **/
248    ////////////////////////////////////////////////////
249
250    /** Called whenever an SkEvent is posted to an empty queue, so that the OS
251        can be told to later call Dequeue().
252    */
253    static void SignalNonEmptyQueue();
254    /** Called whenever the delay until the next delayed event changes. If zero is
255        passed, then there are no more queued delay events.
256    */
257    static void SignalQueueTimer(SkMSec delay);
258
259#if defined(SK_BUILD_FOR_WIN)
260    static bool WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
261#endif
262
263private:
264    SkMetaData      fMeta;
265    mutable char*   fType;  // may be characters with low bit set to know that it is not a pointer
266    uint32_t        f32;
267
268    // 'there can be only one' (non-zero) between target-id and target-proc
269    SkEventSinkID   fTargetID;
270    Proc            fTargetProc;
271
272    // these are for our implementation of the event queue
273    SkMSec          fTime;
274    SkEvent*        fNextEvent; // either in the delay or normal event queue
275
276    void initialize(const char* type, size_t typeLen, SkEventSinkID);
277
278    static bool Enqueue(SkEvent* evt);
279    static SkMSec EnqueueTime(SkEvent* evt, SkMSec time);
280    static SkEvent* Dequeue();
281    static bool     QHasEvents();
282};
283
284#endif
285