001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one or more
003 *  contributor license agreements.  See the NOTICE file distributed with
004 *  this work for additional information regarding copyright ownership.
005 *  The ASF licenses this file to You under the Apache License, Version 2.0
006 *  (the "License"); you may not use this file except in compliance with
007 *  the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.commons.compress.harmony.unpack200.bytecode;
018
019import java.util.ArrayList;
020import java.util.Arrays;
021import java.util.Collections;
022import java.util.Comparator;
023import java.util.HashMap;
024import java.util.HashSet;
025import java.util.List;
026import java.util.Map;
027import java.util.TreeSet;
028
029import org.apache.commons.compress.harmony.unpack200.Segment;
030
031/**
032 * The Class constant pool
033 */
034public class ClassConstantPool {
035
036    protected HashSet<ClassFileEntry> entriesContainsSet = new HashSet<>();
037    protected HashSet<ClassFileEntry> othersContainsSet = new HashSet<>();
038
039    private final HashSet<ClassFileEntry> mustStartClassPool = new HashSet<>();
040
041    protected Map<ClassFileEntry, Integer> indexCache;
042
043    private final List<ClassFileEntry> others = new ArrayList<>(500);
044    private final List<ClassFileEntry> entries = new ArrayList<>(500);
045
046    private boolean resolved;
047
048    public ClassFileEntry add(final ClassFileEntry entry) {
049        if (entry instanceof ByteCode) {
050            return null;
051        }
052        if (entry instanceof ConstantPoolEntry) {
053            if (entriesContainsSet.add(entry)) {
054                entries.add(entry);
055            }
056        } else if (othersContainsSet.add(entry)) {
057            others.add(entry);
058        }
059
060        return entry;
061    }
062
063    public void addNestedEntries() {
064        boolean added = true;
065
066        // initial assignment
067        final List<ClassFileEntry> parents = new ArrayList<>(512);
068        final List<ClassFileEntry> children = new ArrayList<>(512);
069
070        // adding old entries
071        parents.addAll(entries);
072        parents.addAll(others);
073
074        // while there any parents to traverse and at least one change in target
075        // storage was made
076        while (added || parents.size() > 0) {
077
078            children.clear();
079
080            final int entriesOriginalSize = entries.size();
081            final int othersOriginalSize = others.size();
082
083            // get the parents' children and add them to buffer
084            // concurrently add parents to target storage
085            for (int indexParents = 0; indexParents < parents.size(); indexParents++) {
086                final ClassFileEntry entry = parents.get(indexParents);
087
088                // traverse children
089                final ClassFileEntry[] entryChildren = entry.getNestedClassFileEntries();
090                children.addAll(Arrays.asList(entryChildren));
091
092                final boolean isAtStart = entry instanceof ByteCode && ((ByteCode) entry).nestedMustStartClassPool();
093
094                if (isAtStart) {
095                    mustStartClassPool.addAll(Arrays.asList(entryChildren));
096                }
097
098                // add parent
099                add(entry);
100            }
101
102            added = !(entries.size() == entriesOriginalSize && others.size() == othersOriginalSize);
103
104            // parents are not needed anymore
105            // children now become parents
106            parents.clear();
107            parents.addAll(children);
108        }
109    }
110
111    public ClassFileEntry addWithNestedEntries(final ClassFileEntry entry) {
112        add(entry);
113        for (final ClassFileEntry nestedEntry : entry.getNestedClassFileEntries()) {
114            addWithNestedEntries(nestedEntry);
115        }
116        return entry;
117    }
118
119    public List<ClassFileEntry> entries() {
120        return Collections.unmodifiableList(entries);
121    }
122
123    public ClassFileEntry get(int i) {
124        if (!resolved) {
125            throw new IllegalStateException("Constant pool is not yet resolved; this does not make any sense");
126        }
127        return entries.get(--i);
128    }
129
130    public int indexOf(final ClassFileEntry entry) {
131        if (!resolved) {
132            throw new IllegalStateException("Constant pool is not yet resolved; this does not make any sense");
133        }
134        if (null == indexCache) {
135            throw new IllegalStateException("Index cache is not initialized!");
136        }
137        final Integer entryIndex = indexCache.get(entry);
138        // If the entry isn't found, answer -1, otherwise answer the entry.
139        if (entryIndex != null) {
140            return entryIndex.intValue() + 1;
141        }
142        return -1;
143    }
144
145    private void initialSort() {
146        final TreeSet<ClassFileEntry> inCpAll = new TreeSet<>(
147                Comparator.comparingInt(arg0 -> ((ConstantPoolEntry) arg0).getGlobalIndex()));
148        final TreeSet<ClassFileEntry> cpUtf8sNotInCpAll = new TreeSet<>(
149                Comparator.comparing(arg0 -> ((CPUTF8) arg0).underlyingString()));
150        final TreeSet<ClassFileEntry> cpClassesNotInCpAll = new TreeSet<>(
151                Comparator.comparing(arg0 -> ((CPClass) arg0).getName()));
152
153        for (final ClassFileEntry entry2 : entries) {
154            final ConstantPoolEntry entry = (ConstantPoolEntry) entry2;
155            if (entry.getGlobalIndex() == -1) {
156                if (entry instanceof CPUTF8) {
157                    cpUtf8sNotInCpAll.add(entry);
158                } else if (entry instanceof CPClass) {
159                    cpClassesNotInCpAll.add(entry);
160                } else {
161                    throw new Error("error");
162                }
163            } else {
164                inCpAll.add(entry);
165            }
166        }
167        entries.clear();
168        entries.addAll(inCpAll);
169        entries.addAll(cpUtf8sNotInCpAll);
170        entries.addAll(cpClassesNotInCpAll);
171    }
172
173    public void resolve(final Segment segment) {
174        initialSort();
175        sortClassPool();
176
177        resolved = true;
178
179        entries.forEach(entry -> entry.resolve(this));
180        others.forEach(entry -> entry.resolve(this));
181    }
182
183    public int size() {
184        return entries.size();
185    }
186
187    protected void sortClassPool() {
188        // Now that everything has been resolved, do one
189        // final sort of the class pool. This fixes up
190        // references to objects which need to be at the
191        // start of the class pool
192
193        final List<ClassFileEntry> startOfPool = new ArrayList<>(entries.size());
194        final List<ClassFileEntry> finalSort = new ArrayList<>(entries.size());
195
196        for (final ClassFileEntry entry : entries) {
197            if (mustStartClassPool.contains(entry)) {
198                startOfPool.add(entry);
199            } else {
200                finalSort.add(entry);
201            }
202        }
203
204        // copy over and rebuild the cache
205        //
206        indexCache = new HashMap<>(entries.size());
207        int index = 0;
208
209        entries.clear();
210
211        for (final ClassFileEntry entry : startOfPool) {
212            indexCache.put(entry, Integer.valueOf(index));
213
214            if (entry instanceof CPLong || entry instanceof CPDouble) {
215                entries.add(entry); // these get 2 slots because of their size
216                entries.add(entry);
217                index += 2;
218            } else {
219                entries.add(entry);
220                index += 1;
221            }
222        }
223
224        for (final ClassFileEntry entry : finalSort) {
225            indexCache.put(entry, Integer.valueOf(index));
226
227            if (entry instanceof CPLong || entry instanceof CPDouble) {
228                entries.add(entry); // these get 2 slots because of their size
229                entries.add(entry);
230                index += 2;
231            } else {
232                entries.add(entry);
233                index += 1;
234            }
235        }
236
237    }
238}