cn.wjybxx.dson.text.DsonPrinter Maven / Gradle / Ivy
/*
* Copyright 2023-2024 wjybxx([email protected])
*
* 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.
*/
package cn.wjybxx.dson.text;
import cn.wjybxx.base.io.ByteBufferUtils;
import cn.wjybxx.base.io.StringBuilderWriter;
import cn.wjybxx.dson.io.DsonIOException;
import java.io.Writer;
import java.util.Arrays;
/**
* 该接口与{@link DsonScanner}对应
* Printer和Scanner一样是非结构化的，由外层来实现结构化；
*
* @author wjybxx
* date - 2023/6/5
*/
@SuppressWarnings("unused")
public final class DsonPrinter implements AutoCloseable {
/** 默认共享的缩进缓存 -- 4空格 */
private static final char[] SHARED_INDENTION_ARRAY = " ".toCharArray();
private final DsonTextWriterSettings settings;
private final Writer writer;
/** 行缓冲，减少同步写操作 */
private StringBuilder builder;
/** 是否是Writer内部的builder */
private boolean backingBuilder;
/** 缩进字符缓存，减少字符串构建 */
private char[] indentionArray = SHARED_INDENTION_ARRAY;
/** 结构体缩进 -- 默认的body缩进 */
private int structIndent = 0;
/** 当前行号 - 1开始 */
private int ln;
/** 当前列号 */
private int column;
public DsonPrinter(DsonTextWriterSettings settings, Writer writer) {
this.settings = settings;
this.writer = writer;
// 初始化
if (settings.accessBackingBuilder && writer instanceof StringBuilderWriter sbWriter) {
backingBuilder = true;
builder = sbWriter.getBuilder();
} else {
builder = settings.stringBuilderPool.rent();
}
}
// region 属性
public Writer getWriter() {
return writer;
}
/** 当前行号 - 初始1 */
public int getLn() {
return ln;
}
/** 当前列数 - 初始0 */
public int getColumn() {
return column;
}
/** 获取结构化输出body的最佳开始位置 */
public int getPrettyBodyColum() {
return structIndent;
}
// endregion
// region 普通打印
/**
* tab增加的列不是固定的...
* 所以其它打印字符串的方法都必须调用该方法，一定程度上降低了性能，不能批量拷贝
*/
public void print(char c) {
builder.append(c);
if (c == '\t') {
column--;
column += (4 - (column % 4)); // -1 % 4 => -1
} else {
column += 1;
}
}
/** 打印高平面码点 */
public void printHpmCodePoint(char high, char low) {
builder.append(high);
builder.append(low);
column += 1;
}
public void print(char[] cBuffer) {
for (char c : cBuffer) {
print(c);
}
}
public void print(char[] cBuffer, int offset, int len) {
ByteBufferUtils.checkBuffer(cBuffer.length, offset, len);
for (int idx = offset, end = offset + len; idx < end; idx++) {
print(cBuffer[idx]);
}
}
public void print(CharSequence text) {
for (int idx = 0, end = text.length(); idx < end; idx++) {
print(text.charAt(idx));
}
}
public void printFastPath(char c) {
builder.append(c);
column++;
}
/** @param cBuffer 内容中无tab字符 */
public void printFastPath(char[] cBuffer) {
builder.append(cBuffer);
column += cBuffer.length;
}
/** @param cBuffer 内容中无tab字符 */
public void printFastPath(char[] cBuffer, int offset, int len) {
builder.append(cBuffer, offset, len);
column += len;
}
/** @param text 内容中无tab字符 */
public void printFastPath(CharSequence text) {
builder.append(text);
column += text.length();
}
/** @param text 内容中无tab字符 */
public void printRangeFastPath(CharSequence text, int start, int end) {
builder.append(text, start, end);
column += (end - start);
}
// endregion
// region dson
public void printBeginObject() {
builder.append('{');
column += 1;
}
public void printEndObject() {
builder.append('}');
column += 1;
}
public void printBeginArray() {
builder.append('[');
column += 1;
}
public void printEndArray() {
builder.append(']');
column += 1;
}
public void printBeginHeader() {
builder.append("@{");
column += 2;
}
/** 打印冒号 */
public void printColon() {
builder.append(':');
column += 1;
}
/** 打印逗号 */
public void printComma() {
builder.append(',');
column += 1;
}
/** 打印可能需要转义的字符 */
public void printEscaped(char c, boolean unicodeChar) {
StringBuilder sb = builder;
switch (c) {
case '\"' -> {
sb.append('\\');
sb.append('"');
column += 2;
}
case '\\' -> {
sb.append('\\');
sb.append('\\');
column += 2;
}
case '\b' -> {
sb.append('\\');
sb.append('b');
column += 2;
}
case '\f' -> {
sb.append('\\');
sb.append('f');
column += 2;
}
case '\n' -> {
sb.append('\\');
sb.append('n');
column += 2;
}
case '\r' -> {
sb.append('\\');
sb.append('r');
column += 2;
}
case '\t' -> {
sb.append('\\');
sb.append('t');
column += 2;
}
default -> {
if (unicodeChar && (c < 32 || c > 126)) {
sb.append('\\');
sb.append('u');
sb.append(Integer.toHexString(0x10000 + (int) c), 1, 5);
column += 6;
} else {
sb.append(c);
column += 1;
}
}
}
}
// endregion
// region 缩进
/** 换行 */
public void println() {
builder.append(settings.lineSeparator);
if (builder.length() >= 4096) {
flush(); // 如果每一行都flush，在数量大的情况下会产生大量的io操作，降低性能
}
ln++;
column = 0;
}
/** 打印全部缩进 */
public void printIndent() {
printSpaces(structIndent);
}
/** 打印一个空格 */
public void printSpace() {
builder.append(' ');
column += 1;
}
/** 打印指定数量的空格 -- char可以静默转int，改名安全些 */
public void printSpaces(int count) {
if (count < 0) throw new IllegalArgumentException();
if (count == 0) return;
if (count <= indentionArray.length) {
builder.append(indentionArray, 0, count);
} else {
char[] chars = new char[count];
Arrays.fill(chars, ' ');
builder.append(chars);
// 尝试缓存下来
if (count - indentionArray.length <= 8) {
indentionArray = chars;
}
}
column += count;
}
public void indent() {
structIndent += 2;
updateIndent();
}
public void retract() {
if (structIndent < 2) {
throw new IllegalStateException("indent must be called before retract");
}
structIndent -= 2;
updateIndent();
}
private void updateIndent() {
if (structIndent > indentionArray.length) {
indentionArray = new char[structIndent];
Arrays.fill(indentionArray, ' ');
}
}
// endregion
// region io
public void flush() {
if (backingBuilder) {
return;
}
try {
StringBuilder builder = this.builder;
if (builder.length() > 0) {
// 显式转cBuffer，避免toString的额外开销
char[] cBuffer = new char[builder.length()];
builder.getChars(0, cBuffer.length, cBuffer, 0);
writer.write(cBuffer, 0, cBuffer.length);
builder.setLength(0);
}
writer.flush();
} catch (Exception e) {
throw DsonIOException.wrap(e);
}
}
@Override
public void close() {
if (builder == null) {
return;
}
try {
flush();
if (!backingBuilder) {
settings.stringBuilderPool.returnOne(builder);
}
builder = null;
if (settings.autoClose) {
writer.close();
}
} catch (Exception e) {
throw DsonIOException.wrap(e);
}
}
// endregion
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