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1
21 package com.db4o;
22
23 import com.db4o.foundation.*;
24 import com.db4o.inside.slots.*;
25
26
31 public abstract class YapMeta {
32
33
37 public abstract byte getIdentifier();
38
39 public abstract int ownLength();
40
41 public abstract void readThis(Transaction trans, YapReader reader);
42
43 public abstract void writeThis(Transaction trans, YapReader writer);
44
45
46 protected int i_id;
48 protected int i_state = 2;
50 final boolean beginProcessing() {
51 if (bitIsTrue(YapConst.PROCESSING)) {
52 return false;
53 }
54 bitTrue(YapConst.PROCESSING);
55 return true;
56 }
57
58 final void bitFalse(int bitPos) {
59 i_state &= ~(1 << bitPos);
60 }
61
62 final boolean bitIsFalse(int bitPos) {
63 return (i_state | (1 << bitPos)) != i_state;
64 }
65
66 final boolean bitIsTrue(int bitPos) {
67 return (i_state | (1 << bitPos)) == i_state;
68 }
69
70 final void bitTrue(int bitPos) {
71 i_state |= (1 << bitPos);
72 }
73
74 void cacheDirty(Collection4 col) {
75 if (!bitIsTrue(YapConst.CACHED_DIRTY)) {
76 bitTrue(YapConst.CACHED_DIRTY);
77 col.add(this);
78 }
79 }
80
81 public void endProcessing() {
82 bitFalse(YapConst.PROCESSING);
83 }
84
85 public int getID() {
86 return i_id;
87 }
88
89 public final boolean isActive() {
90 return bitIsTrue(YapConst.ACTIVE);
91 }
92
93 public boolean isDirty() {
94 return bitIsTrue(YapConst.ACTIVE) && (!bitIsTrue(YapConst.CLEAN));
95 }
96
97 public final boolean isNew(){
98 return i_id == 0;
99 }
100
101 public int linkLength() {
102 return YapConst.ID_LENGTH;
103 }
104
105 final void notCachedDirty() {
106 bitFalse(YapConst.CACHED_DIRTY);
107 }
108
109 public void read(Transaction trans) {
110 try {
111 if (beginProcessing()) {
112 YapReader reader = trans.stream().readReaderByID(trans, getID());
113 if (reader != null) {
114 if (Deploy.debug) {
115 reader.readBegin(getIdentifier());
116 }
117 readThis(trans, reader);
118 setStateOnRead(reader);
119 }
120 endProcessing();
121 }
122 } catch (Throwable  t) {
123 if (Debug.atHome) {
124 t.printStackTrace();
125 }
126 }
127 }
128
129 public void setID(int a_id) {
130 if(DTrace.enabled){
131 DTrace.YAPMETA_SET_ID.log(a_id);
132 }
133 i_id = a_id;
134 }
135
136 public final void setStateClean() {
137 bitTrue(YapConst.ACTIVE);
138 bitTrue(YapConst.CLEAN);
139 }
140
141 public final void setStateDeactivated() {
142 bitFalse(YapConst.ACTIVE);
143 }
144
145 public void setStateDirty() {
146 bitTrue(YapConst.ACTIVE);
147 bitFalse(YapConst.CLEAN);
148 }
149
150 void setStateOnRead(YapReader reader) {
151 if (Deploy.debug) {
152 reader.readEnd();
153 }
154 if (bitIsTrue(YapConst.CACHED_DIRTY)) {
155 setStateDirty();
156 } else {
157 setStateClean();
158 }
159 }
160
161 public final void write(Transaction trans) {
162
163 if (! writeObjectBegin()) {
164 return;
165 }
166
167 if(DTrace.enabled){
168 DTrace.YAPMETA_WRITE.log(getID());
169 }
170
171 YapFile stream = (YapFile)trans.stream();
172
173 int address = 0;
174 int length = ownLength();
175
176 YapReader writer = new YapReader(length);
177
178 if(isNew()){
179 Pointer4 ptr = stream.newSlot(trans, length);
180 setID(ptr._id);
181 address = ptr._address;
182
183 }else{
185 address = stream.getSlot(length);
186 trans.slotFreeOnRollbackCommitSetPointer(i_id, address, length);
187 }
188
189 if (Deploy.debug) {
190 writer.writeBegin(getIdentifier());
191 }
192
193 writeThis(trans, writer);
194
195 if (Deploy.debug) {
196 writer.writeEnd();
197 }
198
199 writer.writeEncrypt(stream, address, 0);
200
201 if (isActive()) {
202 setStateClean();
203 }
204 endProcessing();
205
206 }
207
208 public boolean writeObjectBegin() {
209 if (isDirty()) {
210 return beginProcessing();
211 }
212 return false;
213 }
214
215 public void writeOwnID(Transaction trans, YapReader writer) {
216 write(trans);
217 writer.writeInt(getID());
218 }
219
220
221 }
222 |
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