Android实现Glide/Coil样式图/视频加载框架，Kotlin
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
<uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@android:color/white"
android:padding="1px">
<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="180px"
android:scaleType="centerCrop" />
</LinearLayout>
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.BufferedWriter;
import java.io.Closeable;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A cache that uses a bounded amount of space on a filesystem. Each cache
* entry has a string key and a fixed number of values. Each key must match
* the regex <strong>[a-z0-9_-]{1,120}</strong>. Values are byte sequences,
* accessible as streams or files. Each value must be between {@code 0} and
* {@code Integer.MAX_VALUE} bytes in length.
*
* <p>The cache stores its data in a directory on the filesystem. This
* directory must be exclusive to the cache; the cache may delete or overwrite
* files from its directory. It is an error for multiple processes to use the
* same cache directory at the same time.
*
* <p>This cache limits the number of bytes that it will store on the
* filesystem. When the number of stored bytes exceeds the limit, the cache will
* remove entries in the background until the limit is satisfied. The limit is
* not strict: the cache may temporarily exceed it while waiting for files to be
* deleted. The limit does not include filesystem overhead or the cache
* journal so space-sensitive applications should set a conservative limit.
*
* <p>Clients call {@link #edit} to create or update the values of an entry. An
* entry may have only one editor at one time; if a value is not available to be
* edited then {@link #edit} will return null.
* <ul>
* <li>When an entry is being <strong>created</strong> it is necessary to
* supply a full set of values; the empty value should be used as a
* placeholder if necessary.
* <li>When an entry is being <strong>edited</strong>, it is not necessary
* to supply data for every value; values default to their previous
* value.
* </ul>
* Every {@link #edit} call must be matched by a call to {@link Editor#commit}
* or {@link Editor#abort}. Committing is atomic: a read observes the full set
* of values as they were before or after the commit, but never a mix of values.
*
* <p>Clients call {@link #get} to read a snapshot of an entry. The read will
* observe the value at the time that {@link #get} was called. Updates and
* removals after the call do not impact ongoing reads.
*
* <p>This class is tolerant of some I/O errors. If files are missing from the
* filesystem, the corresponding entries will be dropped from the cache. If
* an error occurs while writing a cache value, the edit will fail silently.
* Callers should handle other problems by catching {@code IOException} and
* responding appropriately.
*/
public final class DiskLruCache implements Closeable {
static final String JOURNAL_FILE = "journal";
static final String JOURNAL_FILE_TEMP = "journal.tmp";
static final String JOURNAL_FILE_BACKUP = "journal.bkp";
static final String MAGIC = "libcore.io.DiskLruCache";
static final String VERSION_1 = "1";
static final long ANY_SEQUENCE_NUMBER = -1;
static final String STRING_KEY_PATTERN = "[a-z0-9_-]{1,120}";
static final Pattern LEGAL_KEY_PATTERN = Pattern.compile(STRING_KEY_PATTERN);
private static final String CLEAN = "CLEAN";
private static final String DIRTY = "DIRTY";
private static final String REMOVE = "REMOVE";
private static final String READ = "READ";
/*
* This cache uses a journal file named "journal". A typical journal file
* looks like this:
* libcore.io.DiskLruCache
* 1
* 100
* 2
*
* CLEAN 3400330d1dfc7f3f7f4b8d4d803dfcf6 832 21054
* DIRTY 335c4c6028171cfddfbaae1a9c313c52
* CLEAN 335c4c6028171cfddfbaae1a9c313c52 3934 2342
* REMOVE 335c4c6028171cfddfbaae1a9c313c52
* DIRTY 1ab96a171faeeee38496d8b330771a7a
* CLEAN 1ab96a171faeeee38496d8b330771a7a 1600 234
* READ 335c4c6028171cfddfbaae1a9c313c52
* READ 3400330d1dfc7f3f7f4b8d4d803dfcf6
*
* The first five lines of the journal form its header. They are the
* constant string "libcore.io.DiskLruCache", the disk cache's version,
* the application's version, the value count, and a blank line.
*
* Each of the subsequent lines in the file is a record of the state of a
* cache entry. Each line contains space-separated values: a state, a key,
* and optional state-specific values.
* o DIRTY lines track that an entry is actively being created or updated.
* Every successful DIRTY action should be followed by a CLEAN or REMOVE
* action. DIRTY lines without a matching CLEAN or REMOVE indicate that
* temporary files may need to be deleted.
* o CLEAN lines track a cache entry that has been successfully published
* and may be read. A publish line is followed by the lengths of each of
* its values.
* o READ lines track accesses for LRU.
* o REMOVE lines track entries that have been deleted.
*
* The journal file is appended to as cache operations occur. The journal may
* occasionally be compacted by dropping redundant lines. A temporary file named
* "journal.tmp" will be used during compaction; that file should be deleted if
* it exists when the cache is opened.
*/
private final File directory;
private final File journalFile;
private final File journalFileTmp;
private final File journalFileBackup;
private final int appVersion;
private long maxSize;
private final int valueCount;
private long size = 0;
private Writer journalWriter;
private final LinkedHashMap<String, Entry> lruEntries =
new LinkedHashMap<String, Entry>(0, 0.75f, true);
private int redundantOpCount;
/**
* To differentiate between old and current snapshots, each entry is given
* a sequence number each time an edit is committed. A snapshot is stale if
* its sequence number is not equal to its entry's sequence number.
*/
private long nextSequenceNumber = 0;
/** This cache uses a single background thread to evict entries. */
final ThreadPoolExecutor executorService =
new ThreadPoolExecutor(0, 1, 60L, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
private final Callable<Void> cleanupCallable = new Callable<Void>() {
public Void call() throws Exception {
synchronized (DiskLruCache.this) {
if (journalWriter == null) {
return null; // Closed.
}
trimToSize();
if (journalRebuildRequired()) {
rebuildJournal();
redundantOpCount = 0;
}
}
return null;
}
};
private DiskLruCache(File directory, int appVersion, int valueCount, long maxSize) {
this.directory = directory;
this.appVersion = appVersion;
this.journalFile = new File(directory, JOURNAL_FILE);
this.journalFileTmp = new File(directory, JOURNAL_FILE_TEMP);
this.journalFileBackup = new File(directory, JOURNAL_FILE_BACKUP);
this.valueCount = valueCount;
this.maxSize = maxSize;
}
/**
* Opens the cache in {@code directory}, creating a cache if none exists
* there.
*
* @param directory a writable directory
* @param valueCount the number of values per cache entry. Must be positive.
* @param maxSize the maximum number of bytes this cache should use to store
* @throws IOException if reading or writing the cache directory fails
*/
public static DiskLruCache open(File directory, int appVersion, int valueCount, long maxSize)
throws IOException {
if (maxSize <= 0) {
throw new IllegalArgumentException("maxSize <= 0");
}
if (valueCount <= 0) {
throw new IllegalArgumentException("valueCount <= 0");
}
// If a bkp file exists, use it instead.
File backupFile = new File(directory, JOURNAL_FILE_BACKUP);
if (backupFile.exists()) {
File journalFile = new File(directory, JOURNAL_FILE);
// If journal file also exists just delete backup file.
if (journalFile.exists()) {
backupFile.delete();
} else {
renameTo(backupFile, journalFile, false);
}
}
// Prefer to pick up where we left off.
DiskLruCache cache = new DiskLruCache(directory, appVersion, valueCount, maxSize);
if (cache.journalFile.exists()) {
try {
cache.readJournal();
cache.processJournal();
return cache;
} catch (IOException journalIsCorrupt) {
System.out
.println("DiskLruCache "
+ directory
+ " is corrupt: "
+ journalIsCorrupt.getMessage()
+ ", removing");
cache.delete();
}
}
// Create a new empty cache.
directory.mkdirs();
cache = new DiskLruCache(directory, appVersion, valueCount, maxSize);
cache.rebuildJournal();
return cache;
}
private void readJournal() throws IOException {
StrictLineReader reader = new StrictLineReader(new FileInputStream(journalFile), Util.US_ASCII);
try {
String magic = reader.readLine();
String version = reader.readLine();
String appVersionString = reader.readLine();
String valueCountString = reader.readLine();
String blank = reader.readLine();
if (!MAGIC.equals(magic)
|| !VERSION_1.equals(version)
|| !Integer.toString(appVersion).equals(appVersionString)
|| !Integer.toString(valueCount).equals(valueCountString)
|| !"".equals(blank)) {
throw new IOException("unexpected journal header: [" + magic + ", " + version + ", "
+ valueCountString + ", " + blank + "]");
}
int lineCount = 0;
while (true) {
try {
readJournalLine(reader.readLine());
lineCount++;
} catch (EOFException endOfJournal) {
break;
}
}
redundantOpCount = lineCount - lruEntries.size();
// If we ended on a truncated line, rebuild the journal before appending to it.
if (reader.hasUnterminatedLine()) {
rebuildJournal();
} else {
journalWriter = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(journalFile, true), Util.US_ASCII));
}
} finally {
Util.closeQuietly(reader);
}
}
private void readJournalLine(String line) throws IOException {
int firstSpace = line.indexOf(' ');
if (firstSpace == -1) {
throw new IOException("unexpected journal line: " + line);
}
int keyBegin = firstSpace + 1;
int secondSpace = line.indexOf(' ', keyBegin);
final String key;
if (secondSpace == -1) {
key = line.substring(keyBegin);
if (firstSpace == REMOVE.length() && line.startsWith(REMOVE)) {
lruEntries.remove(key);
return;
}
} else {
key = line.substring(keyBegin, secondSpace);
}
Entry entry = lruEntries.get(key);
if (entry == null) {
entry = new Entry(key);
lruEntries.put(key, entry);
}
if (secondSpace != -1 && firstSpace == CLEAN.length() && line.startsWith(CLEAN)) {
String[] parts = line.substring(secondSpace + 1).split(" ");
entry.readable = true;
entry.currentEditor = null;
entry.setLengths(parts);
} else if (secondSpace == -1 && firstSpace == DIRTY.length() && line.startsWith(DIRTY)) {
entry.currentEditor = new Editor(entry);
} else if (secondSpace == -1 && firstSpace == READ.length() && line.startsWith(READ)) {
// This work was already done by calling lruEntries.get().
} else {
throw new IOException("unexpected journal line: " + line);
}
}
/**
* Computes the initial size and collects garbage as a part of opening the
* cache. Dirty entries are assumed to be inconsistent and will be deleted.
*/
private void processJournal() throws IOException {
deleteIfExists(journalFileTmp);
for (Iterator<Entry> i = lruEntries.values().iterator(); i.hasNext(); ) {
Entry entry = i.next();
if (entry.currentEditor == null) {
for (int t = 0; t < valueCount; t++) {
size += entry.lengths[t];
}
} else {
entry.currentEditor = null;
for (int t = 0; t < valueCount; t++) {
deleteIfExists(entry.getCleanFile(t));
deleteIfExists(entry.getDirtyFile(t));
}
i.remove();
}
}
}
/**
* Creates a new journal that omits redundant information. This replaces the
* current journal if it exists.
*/
private synchronized void rebuildJournal() throws IOException {
if (journalWriter != null) {
journalWriter.close();
}
Writer writer = new BufferedWriter(
new OutputStreamWriter(new FileOutputStream(journalFileTmp), Util.US_ASCII));
try {
writer.write(MAGIC);
writer.write("\n");
writer.write(VERSION_1);
writer.write("\n");
writer.write(Integer.toString(appVersion));
writer.write("\n");
writer.write(Integer.toString(valueCount));
writer.write("\n");
writer.write("\n");
for (Entry entry : lruEntries.values()) {
if (entry.currentEditor != null) {
writer.write(DIRTY + ' ' + entry.key + '\n');
} else {
writer.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n');
}
}
} finally {
writer.close();
}
if (journalFile.exists()) {
renameTo(journalFile, journalFileBackup, true);
}
renameTo(journalFileTmp, journalFile, false);
journalFileBackup.delete();
journalWriter = new BufferedWriter(
new OutputStreamWriter(new FileOutputStream(journalFile, true), Util.US_ASCII));
}
private static void deleteIfExists(File file) throws IOException {
if (file.exists() && !file.delete()) {
throw new IOException();
}
}
private static void renameTo(File from, File to, boolean deleteDestination) throws IOException {
if (deleteDestination) {
deleteIfExists(to);
}
if (!from.renameTo(to)) {
throw new IOException();
}
}
/**
* Returns a snapshot of the entry named {@code key}, or null if it doesn't
* exist is not currently readable. If a value is returned, it is moved to
* the head of the LRU queue.
*/
public synchronized Snapshot get(String key) throws IOException {
checkNotClosed();
validateKey(key);
Entry entry = lruEntries.get(key);
if (entry == null) {
return null;
}
if (!entry.readable) {
return null;
}
// Open all streams eagerly to guarantee that we see a single published
// snapshot. If we opened streams lazily then the streams could come
// from different edits.
InputStream[] ins = new InputStream[valueCount];
try {
for (int i = 0; i < valueCount; i++) {
ins[i] = new FileInputStream(entry.getCleanFile(i));
}
} catch (FileNotFoundException e) {
// A file must have been deleted manually!
for (int i = 0; i < valueCount; i++) {
if (ins[i] != null) {
Util.closeQuietly(ins[i]);
} else {
break;
}
}
return null;
}
redundantOpCount++;
journalWriter.append(READ + ' ' + key + '\n');
if (journalRebuildRequired()) {
executorService.submit(cleanupCallable);
}
return new Snapshot(key, entry.sequenceNumber, ins, entry.lengths);
}
/**
* Returns an editor for the entry named {@code key}, or null if another
* edit is in progress.
*/
public Editor edit(String key) throws IOException {
return edit(key, ANY_SEQUENCE_NUMBER);
}
private synchronized Editor edit(String key, long expectedSequenceNumber) throws IOException {
checkNotClosed();
validateKey(key);
Entry entry = lruEntries.get(key);
if (expectedSequenceNumber != ANY_SEQUENCE_NUMBER && (entry == null
|| entry.sequenceNumber != expectedSequenceNumber)) {
return null; // Snapshot is stale.
}
if (entry == null) {
entry = new Entry(key);
lruEntries.put(key, entry);
} else if (entry.currentEditor != null) {
return null; // Another edit is in progress.
}
Editor editor = new Editor(entry);
entry.currentEditor = editor;
// Flush the journal before creating files to prevent file leaks.
journalWriter.write(DIRTY + ' ' + key + '\n');
journalWriter.flush();
return editor;
}
/** Returns the directory where this cache stores its data. */
public File getDirectory() {
return directory;
}
/**
* Returns the maximum number of bytes that this cache should use to store
* its data.
*/
public synchronized long getMaxSize() {
return maxSize;
}
/**
* Changes the maximum number of bytes the cache can store and queues a job
* to trim the existing store, if necessary.
*/
public synchronized void setMaxSize(long maxSize) {
this.maxSize = maxSize;
executorService.submit(cleanupCallable);
}
/**
* Returns the number of bytes currently being used to store the values in
* this cache. This may be greater than the max size if a background
* deletion is pending.
*/
public synchronized long size() {
return size;
}
private synchronized void completeEdit(Editor editor, boolean success) throws IOException {
Entry entry = editor.entry;
if (entry.currentEditor != editor) {
throw new IllegalStateException();
}
// If this edit is creating the entry for the first time, every index must have a value.
if (success && !entry.readable) {
for (int i = 0; i < valueCount; i++) {
if (!editor.written[i]) {
editor.abort();
throw new IllegalStateException("Newly created entry didn't create value for index " + i);
}
if (!entry.getDirtyFile(i).exists()) {
editor.abort();
return;
}
}
}
for (int i = 0; i < valueCount; i++) {
File dirty = entry.getDirtyFile(i);
if (success) {
if (dirty.exists()) {
File clean = entry.getCleanFile(i);
dirty.renameTo(clean);
long oldLength = entry.lengths[i];
long newLength = clean.length();
entry.lengths[i] = newLength;
size = size - oldLength + newLength;
}
} else {
deleteIfExists(dirty);
}
}
redundantOpCount++;
entry.currentEditor = null;
if (entry.readable | success) {
entry.readable = true;
journalWriter.write(CLEAN + ' ' + entry.key + entry.getLengths() + '\n');
if (success) {
entry.sequenceNumber = nextSequenceNumber++;
}
} else {
lruEntries.remove(entry.key);
journalWriter.write(REMOVE + ' ' + entry.key + '\n');
}
journalWriter.flush();
if (size > maxSize || journalRebuildRequired()) {
executorService.submit(cleanupCallable);
}
}
/**
* We only rebuild the journal when it will halve the size of the journal
* and eliminate at least 2000 ops.
*/
private boolean journalRebuildRequired() {
final int redundantOpCompactThreshold = 2000;
return redundantOpCount >= redundantOpCompactThreshold //
&& redundantOpCount >= lruEntries.size();
}
/**
* Drops the entry for {@code key} if it exists and can be removed. Entries
* actively being edited cannot be removed.
*
* @return true if an entry was removed.
*/
public synchronized boolean remove(String key) throws IOException {
checkNotClosed();
validateKey(key);
Entry entry = lruEntries.get(key);
if (entry == null || entry.currentEditor != null) {
return false;
}
for (int i = 0; i < valueCount; i++) {
File file = entry.getCleanFile(i);
if (file.exists() && !file.delete()) {
throw new IOException("failed to delete " + file);
}
size -= entry.lengths[i];
entry.lengths[i] = 0;
}
redundantOpCount++;
journalWriter.append(REMOVE + ' ' + key + '\n');
lruEntries.remove(key);
if (journalRebuildRequired()) {
executorService.submit(cleanupCallable);
}
return true;
}
/** Returns true if this cache has been closed. */
public synchronized boolean isClosed() {
return journalWriter == null;
}
private void checkNotClosed() {
if (journalWriter == null) {
throw new IllegalStateException("cache is closed");
}
}
/** Force buffered operations to the filesystem. */
public synchronized void flush() throws IOException {
checkNotClosed();
trimToSize();
journalWriter.flush();
}
/** Closes this cache. Stored values will remain on the filesystem. */
public synchronized void close() throws IOException {
if (journalWriter == null) {
return; // Already closed.
}
for (Entry entry : new ArrayList<Entry>(lruEntries.values())) {
if (entry.currentEditor != null) {
entry.currentEditor.abort();
}
}
trimToSize();
journalWriter.close();
journalWriter = null;
}
private void trimToSize() throws IOException {
while (size > maxSize) {
Map.Entry<String, Entry> toEvict = lruEntries.entrySet().iterator().next();
remove(toEvict.getKey());
}
}
/**
* Closes the cache and deletes all of its stored values. This will delete
* all files in the cache directory including files that weren't created by
* the cache.
*/
public void delete() throws IOException {
close();
Util.deleteContents(directory);
}
private void validateKey(String key) {
Matcher matcher = LEGAL_KEY_PATTERN.matcher(key);
if (!matcher.matches()) {
throw new IllegalArgumentException("keys must match regex "
+ STRING_KEY_PATTERN + ": \"" + key + "\"");
}
}
private static String inputStreamToString(InputStream in) throws IOException {
return Util.readFully(new InputStreamReader(in, Util.UTF_8));
}
/** A snapshot of the values for an entry. */
public final class Snapshot implements Closeable {
private final String key;
private final long sequenceNumber;
private final InputStream[] ins;
private final long[] lengths;
private Snapshot(String key, long sequenceNumber, InputStream[] ins, long[] lengths) {
this.key = key;
this.sequenceNumber = sequenceNumber;
this.ins = ins;
this.lengths = lengths;
}
/**
* Returns an editor for this snapshot's entry, or null if either the
* entry has changed since this snapshot was created or if another edit
* is in progress.
*/
public Editor edit() throws IOException {
return DiskLruCache.this.edit(key, sequenceNumber);
}
/** Returns the unbuffered stream with the value for {@code index}. */
public InputStream getInputStream(int index) {
return ins[index];
}
/** Returns the string value for {@code index}. */
public String getString(int index) throws IOException {
return inputStreamToString(getInputStream(index));
}
/** Returns the byte length of the value for {@code index}. */
public long getLength(int index) {
return lengths[index];
}
public void close() {
for (InputStream in : ins) {
Util.closeQuietly(in);
}
}
}
private static final OutputStream NULL_OUTPUT_STREAM = new OutputStream() {
@Override
public void write(int b) throws IOException {
// Eat all writes silently. Nom nom.
}
};
/** Edits the values for an entry. */
public final class Editor {
private final Entry entry;
private final boolean[] written;
private boolean hasErrors;
private boolean committed;
private Editor(Entry entry) {
this.entry = entry;
this.written = (entry.readable) ? null : new boolean[valueCount];
}
/**
* Returns an unbuffered input stream to read the last committed value,
* or null if no value has been committed.
*/
public InputStream newInputStream(int index) throws IOException {
synchronized (DiskLruCache.this) {
if (entry.currentEditor != this) {
throw new IllegalStateException();
}
if (!entry.readable) {
return null;
}
try {
return new FileInputStream(entry.getCleanFile(index));
} catch (FileNotFoundException e) {
return null;
}
}
}
/**
* Returns the last committed value as a string, or null if no value
* has been committed.
*/
public String getString(int index) throws IOException {
InputStream in = newInputStream(index);
return in != null ? inputStreamToString(in) : null;
}
/**
* Returns a new unbuffered output stream to write the value at
* {@code index}. If the underlying output stream encounters errors
* when writing to the filesystem, this edit will be aborted when
* {@link #commit} is called. The returned output stream does not throw
* IOExceptions.
*/
public OutputStream newOutputStream(int index) throws IOException {
if (index < 0 || index >= valueCount) {
throw new IllegalArgumentException("Expected index " + index + " to "
+ "be greater than 0 and less than the maximum value count "
+ "of " + valueCount);
}
synchronized (DiskLruCache.this) {
if (entry.currentEditor != this) {
throw new IllegalStateException();
}
if (!entry.readable) {
written[index] = true;
}
File dirtyFile = entry.getDirtyFile(index);
FileOutputStream outputStream;
try {
outputStream = new FileOutputStream(dirtyFile);
} catch (FileNotFoundException e) {
// Attempt to recreate the cache directory.
directory.mkdirs();
try {
outputStream = new FileOutputStream(dirtyFile);
} catch (FileNotFoundException e2) {
// We are unable to recover. Silently eat the writes.
return NULL_OUTPUT_STREAM;
}
}
return new FaultHidingOutputStream(outputStream);
}
}
/** Sets the value at {@code index} to {@code value}. */
public void set(int index, String value) throws IOException {
Writer writer = null;
try {
writer = new OutputStreamWriter(newOutputStream(index), Util.UTF_8);
writer.write(value);
} finally {
Util.closeQuietly(writer);
}
}
/**
* Commits this edit so it is visible to readers. This releases the
* edit lock so another edit may be started on the same key.
*/
public void commit() throws IOException {
if (hasErrors) {
completeEdit(this, false);
remove(entry.key); // The previous entry is stale.
} else {
completeEdit(this, true);
}
committed = true;
}
/**
* Aborts this edit. This releases the edit lock so another edit may be
* started on the same key.
*/
public void abort() throws IOException {
completeEdit(this, false);
}
public void abortUnlessCommitted() {
if (!committed) {
try {
abort();
} catch (IOException ignored) {
}
}
}
private class FaultHidingOutputStream extends FilterOutputStream {
private FaultHidingOutputStream(OutputStream out) {
super(out);
}
@Override public void write(int oneByte) {
try {
out.write(oneByte);
} catch (IOException e) {
hasErrors = true;
}
}
@Override public void write(byte[] buffer, int offset, int length) {
try {
out.write(buffer, offset, length);
} catch (IOException e) {
hasErrors = true;
}
}
@Override public void close() {
try {
out.close();
} catch (IOException e) {
hasErrors = true;
}
}
@Override public void flush() {
try {
out.flush();
} catch (IOException e) {
hasErrors = true;
}
}
}
}
private final class Entry {
private final String key;
/** Lengths of this entry's files. */
private final long[] lengths;
/** True if this entry has ever been published. */
private boolean readable;
/** The ongoing edit or null if this entry is not being edited. */
private Editor currentEditor;
/** The sequence number of the most recently committed edit to this entry. */
private long sequenceNumber;
private Entry(String key) {
this.key = key;
this.lengths = new long[valueCount];
}
public String getLengths() throws IOException {
StringBuilder result = new StringBuilder();
for (long size : lengths) {
result.append(' ').append(size);
}
return result.toString();
}
/** Set lengths using decimal numbers like "10123". */
private void setLengths(String[] strings) throws IOException {
if (strings.length != valueCount) {
throw invalidLengths(strings);
}
try {
for (int i = 0; i < strings.length; i++) {
lengths[i] = Long.parseLong(strings[i]);
}
} catch (NumberFormatException e) {
throw invalidLengths(strings);
}
}
private IOException invalidLengths(String[] strings) throws IOException {
throw new IOException("unexpected journal line: " + java.util.Arrays.toString(strings));
}
public File getCleanFile(int i) {
return new File(directory, key + "." + i);
}
public File getDirtyFile(int i) {
return new File(directory, key + "." + i + ".tmp");
}
}
}
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
/**
* Buffers input from an {@link InputStream} for reading lines.
*
* <p>This class is used for buffered reading of lines. For purposes of this class, a line ends
* with "\n" or "\r\n". End of input is reported by throwing {@code EOFException}. Unterminated
* line at end of input is invalid and will be ignored, the caller may use {@code
* hasUnterminatedLine()} to detect it after catching the {@code EOFException}.
*
* <p>This class is intended for reading input that strictly consists of lines, such as line-based
* cache entries or cache journal. Unlike the {@link java.io.BufferedReader} which in conjunction
* with {@link java.io.InputStreamReader} provides similar functionality, this class uses different
* end-of-input reporting and a more restrictive definition of a line.
*
* <p>This class supports only charsets that encode '\r' and '\n' as a single byte with value 13
* and 10, respectively, and the representation of no other character contains these values.
* We currently check in constructor that the charset is one of US-ASCII, UTF-8 and ISO-8859-1.
* The default charset is US_ASCII.
*/
class StrictLineReader implements Closeable {
private static final byte CR = (byte) '\r';
private static final byte LF = (byte) '\n';
private final InputStream in;
private final Charset charset;
/*
* Buffered data is stored in {@code buf}. As long as no exception occurs, 0 <= pos <= end
* and the data in the range [pos, end) is buffered for reading. At end of input, if there is
* an unterminated line, we set end == -1, otherwise end == pos. If the underlying
* {@code InputStream} throws an {@code IOException}, end may remain as either pos or -1.
*/
private byte[] buf;
private int pos;
private int end;
/**
* Constructs a new {@code LineReader} with the specified charset and the default capacity.
*
* @param in the {@code InputStream} to read data from.
* @param charset the charset used to decode data. Only US-ASCII, UTF-8 and ISO-8859-1 are
* supported.
* @throws NullPointerException if {@code in} or {@code charset} is null.
* @throws IllegalArgumentException if the specified charset is not supported.
*/
public StrictLineReader(InputStream in, Charset charset) {
this(in, 8192, charset);
}
/**
* Constructs a new {@code LineReader} with the specified capacity and charset.
*
* @param in the {@code InputStream} to read data from.
* @param capacity the capacity of the buffer.
* @param charset the charset used to decode data. Only US-ASCII, UTF-8 and ISO-8859-1 are
* supported.
* @throws NullPointerException if {@code in} or {@code charset} is null.
* @throws IllegalArgumentException if {@code capacity} is negative or zero
* or the specified charset is not supported.
*/
public StrictLineReader(InputStream in, int capacity, Charset charset) {
if (in == null || charset == null) {
throw new NullPointerException();
}
if (capacity < 0) {
throw new IllegalArgumentException("capacity <= 0");
}
if (!(charset.equals(Util.US_ASCII))) {
throw new IllegalArgumentException("Unsupported encoding");
}
this.in = in;
this.charset = charset;
buf = new byte[capacity];
}
/**
* Closes the reader by closing the underlying {@code InputStream} and
* marking this reader as closed.
*
* @throws IOException for errors when closing the underlying {@code InputStream}.
*/
public void close() throws IOException {
synchronized (in) {
if (buf != null) {
buf = null;
in.close();
}
}
}
/**
* Reads the next line. A line ends with {@code "\n"} or {@code "\r\n"},
* this end of line marker is not included in the result.
*
* @return the next line from the input.
* @throws IOException for underlying {@code InputStream} errors.
* @throws EOFException for the end of source stream.
*/
public String readLine() throws IOException {
synchronized (in) {
if (buf == null) {
throw new IOException("LineReader is closed");
}
// Read more data if we are at the end of the buffered data.
// Though it's an error to read after an exception, we will let {@code fillBuf()}
// throw again if that happens; thus we need to handle end == -1 as well as end == pos.
if (pos >= end) {
fillBuf();
}
// Try to find LF in the buffered data and return the line if successful.
for (int i = pos; i != end; ++i) {
if (buf[i] == LF) {
int lineEnd = (i != pos && buf[i - 1] == CR) ? i - 1 : i;
String res = new String(buf, pos, lineEnd - pos, charset.name());
pos = i + 1;
return res;
}
}
// Let's anticipate up to 80 characters on top of those already read.
ByteArrayOutputStream out = new ByteArrayOutputStream(end - pos + 80) {
@Override
public String toString() {
int length = (count > 0 && buf[count - 1] == CR) ? count - 1 : count;
try {
return new String(buf, 0, length, charset.name());
} catch (UnsupportedEncodingException e) {
throw new AssertionError(e); // Since we control the charset this will never happen.
}
}
};
while (true) {
out.write(buf, pos, end - pos);
// Mark unterminated line in case fillBuf throws EOFException or IOException.
end = -1;
fillBuf();
// Try to find LF in the buffered data and return the line if successful.
for (int i = pos; i != end; ++i) {
if (buf[i] == LF) {
if (i != pos) {
out.write(buf, pos, i - pos);
}
pos = i + 1;
return out.toString();
}
}
}
}
}
public boolean hasUnterminatedLine() {
return end == -1;
}
/**
* Reads new input data into the buffer. Call only with pos == end or end == -1,
* depending on the desired outcome if the function throws.
*/
private void fillBuf() throws IOException {
int result = in.read(buf, 0, buf.length);
if (result == -1) {
throw new EOFException();
}
pos = 0;
end = result;
}
}
/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.nio.charset.Charset;
/** Junk drawer of utility methods. */
final class Util {
static final Charset US_ASCII = Charset.forName("US-ASCII");
static final Charset UTF_8 = Charset.forName("UTF-8");
private Util() {
}
static String readFully(Reader reader) throws IOException {
try {
StringWriter writer = new StringWriter();
char[] buffer = new char[1024];
int count;
while ((count = reader.read(buffer)) != -1) {
writer.write(buffer, 0, count);
}
return writer.toString();
} finally {
reader.close();
}
}
/**
* Deletes the contents of {@code dir}. Throws an IOException if any file
* could not be deleted, or if {@code dir} is not a readable directory.
*/
static void deleteContents(File dir) throws IOException {
File[] files = dir.listFiles();
if (files == null) {
throw new IOException("not a readable directory: " + dir);
}
for (File file : files) {
if (file.isDirectory()) {
deleteContents(file);
}
if (!file.delete()) {
throw new IOException("failed to delete file: " + file);
}
}
}
static void closeQuietly(/*Auto*/Closeable closeable) {
if (closeable != null) {
try {
closeable.close();
} catch (RuntimeException rethrown) {
throw rethrown;
} catch (Exception ignored) {
}
}
}
}
import android.content.Context
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.util.Log
import androidx.annotation.WorkerThread
import androidx.appcompat.app.AppCompatActivity
import androidx.collection.LruCache
import androidx.lifecycle.lifecycleScope
import com.mediaapp.disk.DiskLruCache
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import java.io.File
import java.security.MessageDigest
import java.security.NoSuchAlgorithmException
class BitmapCache {
companion object {
const val TAG = "fly/BitmapCache"
const val MAX_DISK_SIZE: Long = 1024 * 1024 * 1024
const val CACHE_FILE_PATH = "fly_disk_cache"
}
private var mCtx: Context? = null
private var mDiskCache: DiskLruCache? = null
private var mMemoryCache = LruCache<String, Bitmap>(1000)
constructor(ctx: Context) {
mCtx = ctx
val file = File(ctx.cacheDir.path, CACHE_FILE_PATH)
if (!file.exists()) {
file.mkdirs()
}
mDiskCache = DiskLruCache.open(file, 1, 1, MAX_DISK_SIZE)
}
fun getMemoryCache(key: String): Bitmap? {
return mMemoryCache.get(key)
}
@WorkerThread
fun putCache(key: String, bmp: Bitmap) {
putMemoryCache(key, bmp)
putDiskCache(key, bmp)
}
@WorkerThread
fun getCache(key: String): Bitmap? {
var bmp = getMemoryCache(key)
if (bmp != null) {
Log.d(TAG, "内存缓存存在 $key")
return bmp
} else {
bmp = getDiskCache(key)
if (bmp != null) {
Log.d(TAG, "Disk缓存存在 $key")
putMemoryCache(key, bmp!!) //刷新内存的缓存
return bmp
}
}
return null
}
fun putMemoryCache(key: String, bmp: Bitmap) {
mMemoryCache.put(key, bmp)
}
@WorkerThread
private fun getDiskCache(key: String): Bitmap? {
val snapshot = mDiskCache?.get(getMD5(key))
val bmp = BitmapFactory.decodeStream(snapshot?.getInputStream(0))
//mDiskCache?.close()
return bmp
}
@WorkerThread
private fun putDiskCache(key: String, bmp: Bitmap) {
(mCtx as AppCompatActivity).lifecycleScope.launch(Dispatchers.IO) {
val editor = mDiskCache?.edit(getMD5(key))
try {
bmp.compress(Bitmap.CompressFormat.PNG, 100, editor?.newOutputStream(0)!!)
editor.commit()
//mDiskCache?.flush()
//mDiskCache?.close()
Log.d(TAG, "写入成功 $key")
} catch (e: Exception) {
Log.e(TAG, "editor $e $key")
}
}
}
private fun getMD5(msg: String): String {
var md: MessageDigest? = null
try {
md = MessageDigest.getInstance("MD5")
} catch (e: NoSuchAlgorithmException) {
e.printStackTrace()
}
md?.reset()
md?.update(msg.toByteArray())
val bytes = md?.digest()
var result = ""
if (bytes != null) {
for (b in bytes) {
// byte转换成16进制
result += String.format("%02x", b)
}
}
return result
}
}
import android.graphics.Bitmap
import android.util.Log
import wseemann.media.FFmpegMediaMetadataRetriever
class BitmapDecoder : Loader.Decoder {
companion object {
const val TAG = "fly/BitmapDecoder"
}
override fun decode(data: Any?): Bitmap? {
val mData = data as MyData
Log.d(TAG, "开始解码 $mData")
val ffMMR = FFmpegMediaMetadataRetriever()
var bmp: Bitmap? = null
try {
ffMMR.setDataSource(mData.path)
bmp = ffMMR.frameAtTime
} catch (e: Exception) {
Log.e(TAG, "FFmpeg MMR: ${e.message}:$mData")
} finally {
try {
ffMMR.release()
} catch (exc: Exception) {
Log.e(TAG, "$exc")
}
}
return bmp
}
}
import android.content.Context
import android.graphics.Bitmap
class Loader {
companion object {
const val TAG = "fly/Loader"
}
private var mCtx: Context? = null
private var mListener: Listener? = null
private var mBitmapCache: BitmapCache? = null
private var mDecoder: Decoder? = null
private var mData: MyData? = null
constructor(ctx: Context) {
mCtx = ctx
}
fun cache(cache: BitmapCache): Loader {
mBitmapCache = cache
return this
}
fun load(data: MyData): Loader {
mData = data
return this
}
fun start(): Loader {
var bmp: Bitmap?
bmp = mBitmapCache?.getCache(mData.toString())
if (bmp != null) {
mListener?.onSuccess(bmp)
} else {
bmp = mDecoder?.decode(mData)
if (bmp != null) {
mListener?.onSuccess(bmp)
mBitmapCache?.putCache(mData.toString(), bmp)
}
}
mListener?.onError()
return this
}
fun decoder(decoder: Decoder): Loader {
mDecoder = decoder
return this
}
fun setListener(l: Listener): Loader {
mListener = l
return this
}
interface Listener {
fun onSuccess(bitmap: Bitmap) {
}
fun onError() {
}
}
interface Decoder {
fun decode(data: Any?): Bitmap? {
return null
}
}
}
import android.content.ContentUris
import android.content.Context
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
class MainActivity : AppCompatActivity() {
companion object {
const val TAG = "fly/MainActivity"
const val SPAN_COUNT = 6
const val VIDEO = 1
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val rv = findViewById<RecyclerView>(R.id.rv)
val layoutManager = GridLayoutManager(this, SPAN_COUNT)
layoutManager.orientation = GridLayoutManager.VERTICAL
rv.layoutManager = layoutManager
val adapter = MyAdapter(this)
rv.adapter = adapter
rv.layoutManager = layoutManager
val ctx = this
lifecycleScope.launch(Dispatchers.IO) {
val videoList = readAllVideo(ctx)
Log.d(TAG, "readAllVideo size=${videoList.size}")
val lists = arrayListOf<MyData>()
lists.addAll(videoList)
lifecycleScope.launch(Dispatchers.Main) {
adapter.dataChanged(lists)
}
}
}
private fun readAllVideo(ctx: Context): ArrayList<MyData> {
val videos = ArrayList<MyData>()
//读取视频Video
val cursor = ctx.contentResolver.query(
MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
null,
null,
null,
null
)
while (cursor!!.moveToNext()) {
//路径
val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA))
val id = cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)
val videoUri: Uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getLong(id))
//名称
//val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME))
//大小
//val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE))
videos.add(MyData(videoUri, path, VIDEO))
}
cursor.close()
return videos
}
}
import android.content.Context
import android.graphics.Bitmap
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.RecyclerView
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
class MyAdapter : RecyclerView.Adapter<MyAdapter.VideoHolder> {
companion object {
const val TAG = "fly/MyAdapter"
}
private var mCtx: Context? = null
private var mItems = ArrayList<MyData>()
private var mBitmapCache: BitmapCache? = null
constructor(ctx: Context) : super() {
mCtx = ctx
mBitmapCache = BitmapCache(mCtx!!)
}
fun dataChanged(items: ArrayList<MyData>) {
this.mItems = items
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): VideoHolder {
val v = LayoutInflater.from(mCtx).inflate(R.layout.image_layout, null)
return VideoHolder(v)
}
override fun onBindViewHolder(holder: VideoHolder, position: Int) {
loadVideoCover(mItems[position], holder.image)
}
override fun getItemCount(): Int {
return mItems.size
}
class VideoHolder : RecyclerView.ViewHolder {
var image: ImageView? = null
constructor(itemView: View) : super(itemView) {
image = itemView.findViewById<ImageView>(R.id.image)
image?.setImageResource(android.R.drawable.ic_menu_gallery)
}
}
private fun loadVideoCover(data: MyData, image: ImageView?) {
val cacheBmp = mBitmapCache?.getMemoryCache(data.toString())
if (cacheBmp != null) {
image?.setImageBitmap(cacheBmp)
} else {
(mCtx as AppCompatActivity).lifecycleScope.launch(Dispatchers.IO) {
Loader(mCtx!!)
.cache(mBitmapCache!!)
.load(data)
.decoder(BitmapDecoder())
.setListener(object : Loader.Listener {
override fun onSuccess(bitmap: Bitmap) {
(mCtx as AppCompatActivity).lifecycleScope.launch(Dispatchers.Main) {
image?.setImageBitmap(bitmap)
}
}
}).start()
}
}
}
}
import android.net.Uri
import android.text.TextUtils
open class MyData {
var uri: Uri? = null
var path: String? = null
var lastModified = 0L
var width = 0
var height = 0
var position = -1
var type = -1 //-1未知。1，普通图。2，视频。
constructor(uri: Uri?, path: String?, type: Int = -1) {
this.uri = uri
this.path = path
this.type = type
}
override fun equals(other: Any?): Boolean {
return TextUtils.equals(this.toString(), other.toString())
}
override fun toString(): String {
return "MyData(uri=$uri, path=$path, lastModified=$lastModified, width=$width, height=$height, position=$position, type=$type)"
}
}
Android Coil3视频封面抽取封面帧存Disk缓存，Kotlin-CSDN博客文章浏览阅读610次，点赞21次，收藏6次。本文介绍了一个基于Coil3的Android视频封面抽取实现方案。项目通过MediaStore获取设备视频列表，使用MediaMetadataRetriever提取视频首帧作为缩略图，并采用二级缓存（内存+磁盘）优化性能。核心功能包括：1）声明读写存储权限；2）RecyclerView网格布局展示；3）协程处理耗时操作；4）自定义ImageLoader配置缓存策略（最大2GB）。相比原生方案，该实现通过Coil的缓存机制提升了缩略图加载效率，同时处理了视频损坏等异常情况。相关技术细节可参考作者CSDN博客中
https://blog.csdn.net/zhangphil/article/details/150224812
Android快速视频解码抽帧FFmpegMediaMetadataRetriever，Kotlin（2）-CSDN博客文章浏览阅读216次。本文介绍了两种Android视频封面提取方案对比：1)原生MediaMetadataRetriever速度较慢；2)第三方FFmpegMediaMetadataRetriever(FFMMR)实现快速抽帧。详细说明了FFMMR的集成方法（添加依赖和权限），并提供了完整的Kotlin实现代码，包括视频列表读取、缓存管理、协程异步处理等核心功能。通过LruCache缓存缩略图提升性能，记录处理耗时和失败情况。相比前文介绍的原生方案，本文重点突出了FFMMR在解码效率和性能上的优势，为需要快速获取视频帧的场景提供https://blog.csdn.net/zhangphil/article/details/150061648