cn.wjybxx.dson.text.DsonScanner 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.ObjectUtils;
import cn.wjybxx.base.io.LocalStringBuilderPool;
import cn.wjybxx.base.pool.ObjectPool;
import java.util.List;
import java.util.Objects;
/**
* @author wjybxx
* date - 2023/6/2
*/
public class DsonScanner implements AutoCloseable {
private static final List STRING_TOKEN_TYPES = List.of(DsonTokenType.STRING, DsonTokenType.UNQUOTE_STRING);
private DsonCharStream charStream;
private ObjectPool builderPool;
private StringBuilder pooledStringBuilder;
private final CharBuffer hexBuffer = new CharBuffer(4);
public DsonScanner(CharSequence dson) {
this(new StringCharStream(dson), null);
}
public DsonScanner(DsonCharStream charStream) {
this(charStream, null);
}
public DsonScanner(CharSequence dson, ObjectPool builderPool) {
this(DsonCharStream.newCharStream(dson), builderPool);
}
public DsonScanner(DsonCharStream charStream, ObjectPool builderPool) {
this.charStream = Objects.requireNonNull(charStream);
this.builderPool = ObjectUtils.nullToDef(builderPool, LocalStringBuilderPool.INSTANCE);
this.pooledStringBuilder = this.builderPool.rent();
}
@Override
public void close() {
if (charStream != null) {
charStream.close();
charStream = null;
}
if (builderPool != null) {
builderPool.returnOne(pooledStringBuilder);
builderPool = null;
pooledStringBuilder = null;
}
}
public DsonToken nextToken() {
return nextToken(false);
}
/**
* @param skipValue 是否跳过值解析；如果为true，则仅扫描而不截取内容解析；这对于快速扫描确定位置时特别有用
*/
public DsonToken nextToken(boolean skipValue) {
DsonCharStream buffer = charStream;
if (buffer == null) {
throw new DsonParseException("Scanner closed");
}
while (true) {
int c = skipWhitespace();
if (c == -1) {
return new DsonToken(DsonTokenType.EOF, "eof", getPosition());
}
switch (c) {
case '{':
return new DsonToken(DsonTokenType.BEGIN_OBJECT, "{", getPosition());
case '[':
return new DsonToken(DsonTokenType.BEGIN_ARRAY, "[", getPosition());
case '}':
return new DsonToken(DsonTokenType.END_OBJECT, "}", getPosition());
case ']':
return new DsonToken(DsonTokenType.END_ARRAY, "]", getPosition());
case ':':
return new DsonToken(DsonTokenType.COLON, ":", getPosition());
case ',':
return new DsonToken(DsonTokenType.COMMA, ",", getPosition());
case '@':
return parseTypeToken(skipValue);
case '"': {
int indent = buffer.getColumn() - 1;
if (buffer.read() != '"') {
buffer.unread();
} else if (buffer.read() != '"') {
buffer.unread();
buffer.unread();
} else {
if (buffer.read() != -2) {
throw new DsonParseException("Illegal text block start: missing new line after opening quotes, position: " + getPosition());
}
return new DsonToken(DsonTokenType.STRING, scanSimpleText(indent, skipValue), getPosition());
}
return new DsonToken(DsonTokenType.STRING, scanString(skipValue), getPosition());
}
case '/': {
skipComment();
continue;
}
default: {
return new DsonToken(DsonTokenType.UNQUOTE_STRING, scanUnquotedString((char) c, skipValue), getPosition());
}
}
}
}
// region common
private static void ensureStringToken(DsonTokenType tokenType, int position) {
if (tokenType != DsonTokenType.UNQUOTE_STRING && tokenType != DsonTokenType.STRING) {
throw invalidTokenType(STRING_TOKEN_TYPES, tokenType, position);
}
}
private static DsonParseException invalidTokenType(List expected, DsonTokenType tokenType, int position) {
return new DsonParseException(String.format("Invalid Dson Token. Position: %d. Expected: %s. Found: '%s'.",
position, expected, tokenType));
}
private static DsonParseException invalidClassName(String c, int position) {
return new DsonParseException(String.format("Invalid className. Position: %d. ClassName: '%s'.", position, c));
}
private static DsonParseException invalidEscapeSequence(int c, int position) {
return new DsonParseException(String.format("Invalid escape sequence. Position: %d. Character: '\\%c'.", position, c));
}
private static DsonParseException spaceRequired(int position) {
return new DsonParseException(String.format("Space is required. Position: %d.", position));
}
private StringBuilder allocStringBuilder() {
pooledStringBuilder.setLength(0);
return pooledStringBuilder;
}
private int getPosition() {
return charStream.getPosition();
}
// endregion
// region header
private DsonToken parseTypeToken(boolean skipValue) {
DsonCharStream buffer = charStream;
int firstChar = buffer.read();
if (firstChar < 0) {
throw invalidClassName("@", getPosition());
}
// '@{' 对应的是header，header可能是 {k:v} 或 @{clsName} 简写形式 -- 需要判别
if (firstChar == '{') {
return scanHeader();
}
// '@"""' 对应Dson文本块，缩进由行首确定
if (firstChar == '"') {
if (buffer.read() != '"' || buffer.read() != '"') {
throw new DsonParseException("Illegal text block start: missing quotes, position: " + getPosition());
}
if (buffer.read() != -2) {
throw new DsonParseException("Illegal text block start: missing new line after opening quotes, position: " + getPosition());
}
buffer.unread();
return new DsonToken(DsonTokenType.STRING, scanDsonText(skipValue), getPosition());
}
// '@' 对应的是内建值类型，@i @L ...
return scanBuiltinValue(firstChar, skipValue);
}
/** header不处理跳过逻辑 -- 1.header信息很重要 2.header比例较低 */
private DsonToken scanHeader() {
DsonCharStream buffer = this.charStream;
final int beginPos = buffer.getPosition();
int firstChar = skipWhitespace(); // {}下跳过空白字符
if (firstChar < 0) {
throw invalidClassName("@{", getPosition());
}
String className;
if (firstChar == '"') {
className = scanString(false);
} else {
// 非双引号模式下，只能由安全字符构成
if (DsonTexts.isUnsafeStringChar(firstChar)) {
throw invalidClassName(Character.toString((char) firstChar), getPosition());
}
StringBuilder sb = allocStringBuilder();
sb.append((char) firstChar);
int c;
while ((c = buffer.read()) >= 0) {
if (DsonTexts.isUnsafeStringChar(c)) {
break;
}
sb.append((char) c);
}
if (c < 0 || DsonTexts.isUnsafeStringChar(c)) {
buffer.unread();
}
className = sb.toString();
}
// {} 模式下，下一个字符必须是 ':' 或 '}‘
int nextChar = skipWhitespace();
if (nextChar == ':') { // 结构体样式，需要回退
while (buffer.getPosition() > beginPos) {
buffer.unread();
}
return new DsonToken(DsonTokenType.BEGIN_HEADER, "{", beginPos);
} else if (nextChar == '}') { // 简单缩写形式
return new DsonToken(DsonTokenType.SIMPLE_HEADER, className, getPosition());
} else {
throw invalidClassName(className, getPosition());
}
}
/** 内建值无引号，且类型标签后必须是空格或换行缩进 */
private DsonToken scanBuiltinValue(int firstChar, boolean skipValue) {
assert firstChar != '"';
// 非双引号模式下，只能由安全字符构成
if (DsonTexts.isUnsafeStringChar(firstChar)) {
throw invalidClassName(Character.toString((char) firstChar), getPosition());
}
DsonCharStream buffer = this.charStream;
StringBuilder sb = allocStringBuilder();
sb.append((char) firstChar);
int c;
while ((c = buffer.read()) >= 0) {
if (DsonTexts.isUnsafeStringChar(c)) {
break;
}
sb.append((char) c);
}
if (c == -2) {
buffer.unread();
} else if (c != ' ') {
throw spaceRequired(getPosition());
}
String className = sb.toString();
if (ObjectUtils.isBlank(className)) {
throw invalidClassName(className, getPosition());
}
return onReadClassName(className, skipValue);
}
private DsonToken onReadClassName(String className, boolean skipValue) {
final int position = getPosition();
switch (className) {
case DsonTexts.LABEL_INT32 -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.INT32, null, getPosition());
}
return new DsonToken(DsonTokenType.INT32, DsonTexts.parseInt(nextToken.castAsString()), getPosition());
}
case DsonTexts.LABEL_INT64 -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.INT64, null, getPosition());
}
return new DsonToken(DsonTokenType.INT64, DsonTexts.parseLong(nextToken.castAsString()), getPosition());
}
case DsonTexts.LABEL_FLOAT -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.FLOAT, null, getPosition());
}
return new DsonToken(DsonTokenType.FLOAT, DsonTexts.parseFloat(nextToken.castAsString()), getPosition());
}
case DsonTexts.LABEL_DOUBLE -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.DOUBLE, null, getPosition());
}
return new DsonToken(DsonTokenType.DOUBLE, DsonTexts.parseDouble(nextToken.castAsString()), getPosition());
}
case DsonTexts.LABEL_BOOL -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.BOOL, null, getPosition());
}
return new DsonToken(DsonTokenType.BOOL, DsonTexts.parseBool(nextToken.castAsString()), getPosition());
}
case DsonTexts.LABEL_NULL -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
if (skipValue) {
return new DsonToken(DsonTokenType.NULL, null, getPosition());
}
DsonTexts.checkNullString(nextToken.castAsString());
return new DsonToken(DsonTokenType.NULL, null, getPosition());
}
case DsonTexts.LABEL_STRING -> {
DsonToken nextToken = nextToken(skipValue);
ensureStringToken(nextToken.getType(), position);
return new DsonToken(DsonTokenType.STRING, nextToken.castAsString(), getPosition());
}
case DsonTexts.LABEL_STRING_LINE -> {
return new DsonToken(DsonTokenType.STRING, scanSingleLineText(skipValue), getPosition());
}
}
return new DsonToken(DsonTokenType.BUILTIN_STRUCT, className, getPosition());
}
// endregion
// region 字符串
/** @return 如果跳到文件尾则返回 -1 */
private int skipWhitespace() {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2) {
continue;
}
if (c == '/') {
skipComment();
continue;
}
if (!DsonTexts.isIndentChar(c)) {
break;
}
}
return c;
}
/** 跳过双斜杠'//'注释 */
private void skipComment() {
DsonCharStream buffer = this.charStream;
int nextChar = buffer.read();
if (nextChar != '/') {
throw new DsonParseException("invalid comment format: Single slash, position: " + getPosition());
}
buffer.skipLine();
}
/**
* 扫描无引号字符串，无引号字符串不支持切换到独立行
* （该方法只使用扫描元素，不适合扫描标签）
*
* @param firstChar 第一个非空白字符
* @param skipValue 是否跳过值解析
*/
private String scanUnquotedString(final char firstChar, boolean skipValue) {
if (skipValue) {
skipUnquotedString();
return null;
}
StringBuilder sb = allocStringBuilder();
scanUnquotedString(firstChar, sb);
return sb.toString();
}
/** 无引号字符串应该的占比是极高的，skip值得处理 */
private void skipUnquotedString() {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) >= 0) {
if (DsonTexts.isUnsafeStringChar(c)) {
break;
}
}
buffer.unread();
}
private void scanUnquotedString(char firstChar, StringBuilder sb) {
DsonCharStream buffer = this.charStream;
sb.append(firstChar);
int c;
while ((c = buffer.read()) >= 0) {
if (DsonTexts.isUnsafeStringChar(c)) {
break;
}
sb.append((char) c);
}
buffer.unread();
}
/**
* 扫描双引号字符串
*/
private String scanString(boolean skipValue) {
StringBuilder sb = allocStringBuilder();
scanString(sb);
return skipValue ? null : sb.toString();
}
private void scanString(StringBuilder sb) {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2) {
continue;
}
if (c == '"') { // 结束
return;
} else if (c == '\\') { // 处理转义字符
doEscape(buffer, sb);
} else {
sb.append((char) c);
}
}
throw new DsonParseException("End of file in Dson string.");
}
/** 扫描单行纯文本 */
private String scanSingleLineText(boolean skipValue) {
if (skipValue) {
charStream.skipLine();
return null;
}
StringBuilder sb = allocStringBuilder();
scanSingleLineText(sb);
return sb.toString();
}
private void scanSingleLineText(StringBuilder sb) {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) >= 0) {
sb.append((char) c);
}
buffer.unread();
}
/**
* 扫描文本段 -- """
*
* @param indent 缩进数量
*/
private String scanSimpleText(int indent, boolean skipValue) {
if (skipValue) {
skipSimpleText(indent);
return null;
}
StringBuilder sb = allocStringBuilder();
scanSimpleText(sb, indent);
return sb.toString();
}
private void skipSimpleText(int indent) {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2) { // 空行
continue;
}
// 处理缩进
do {
if (buffer.getColumn() > indent) {
break;
}
if (!DsonTexts.isIndentChar(c)) {
throw new DsonParseException("Line does not start with the same whitespace as the opening line of the raw string literal, position: " + getPosition());
}
} while ((c = buffer.read()) >= 0);
// 空行
if (c < 0) {
continue;
}
// 处理结束符
int position = buffer.getPosition();
if (c == '"'
&& buffer.read() == '"'
&& buffer.read() == '"') {
if (buffer.read() == '"') { // 超过3个引号
throw new DsonParseException("Illegal text block end: excessive quotes, position: " + getPosition());
}
buffer.unread();
return; // 结束
}
// 回退到c对应的位置
while (buffer.getPosition() > position) {
buffer.unread();
}
// 跳过后续
buffer.skipLine();
}
}
private void scanSimpleText(StringBuilder sb, int indent) {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2) { // 空行
sb.append('\n');
continue;
}
// 处理缩进
do {
if (buffer.getColumn() > indent) {
break;
}
if (!DsonTexts.isIndentChar(c)) {
throw new DsonParseException("Line does not start with the same whitespace as the opening line of the raw string literal, position: " + getPosition());
}
} while ((c = buffer.read()) >= 0);
// 空行
if (c < 0) {
if (c == -1) {
break; // eof
}
sb.append('\n');
continue;
}
// 处理结束符
int position = buffer.getPosition();
if (c == '"'
&& buffer.read() == '"'
&& buffer.read() == '"') {
if (buffer.read() == '"') { // 超过3个引号
throw new DsonParseException("Illegal text block end: excessive quotes, position: " + getPosition());
}
buffer.unread();
sb.setLength(sb.length() - 1); // 去除最后一个换行符
return; // 结束
}
// 回退到c对应的位置
while (buffer.getPosition() > position) {
buffer.unread();
}
sb.append((char) c);
while ((c = buffer.read()) >= 0) {
sb.append((char) c);
}
// c < 0
if (c == -1) {
break; // Eof
}
sb.append('\n');
}
throw new DsonParseException("End of file in Dson string.");
}
/** 扫描Dson文本段 -- @""" */
private String scanDsonText(boolean skipValue) {
if (skipValue) {
skipDsonText();
return null;
}
StringBuilder sb = allocStringBuilder();
scanDsonText(sb);
return sb.toString();
}
private void skipDsonText() {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2 && readLineHead(buffer) == LineHead.END_OF_TEXT) {
break;
}
}
throw new DsonParseException("End of file in Dson string.");
}
private void scanDsonText(StringBuilder sb) {
DsonCharStream buffer = this.charStream;
int c;
while ((c = buffer.read()) != -1) {
if (c == -2) {
LineHead lineHead = readLineHead(buffer);
if (lineHead == LineHead.END_OF_TEXT) { // 读取结束
return;
}
if (lineHead == LineHead.COMMENT) { // 注释行
buffer.skipLine();
} else if (lineHead == LineHead.APPEND_LINE) { // 开启新行
sb.append('\n');
} else if (lineHead == LineHead.SWITCH_MODE) { // 进入转义模式
switch2EscapeMode(buffer, sb);
}
} else {
sb.append((char) c);
}
}
throw new DsonParseException("End of file in Dson string.");
}
/** 转义模式 - 单行有效 */
private void switch2EscapeMode(DsonCharStream buffer, StringBuilder sb) {
int c;
while ((c = buffer.read()) >= 0) {
if (c == '\\') {
doEscape(buffer, sb);
} else {
sb.append((char) c);
}
}
buffer.unread();
}
private LineHead readLineHead(DsonCharStream buffer) {
int c;
while ((c = buffer.read()) >= 0) {
if (DsonTexts.isIndentChar(c)) {
continue;
}
if (c == '/') { // 注释行
skipComment();
return LineHead.COMMENT;
}
if (c == '"') { // 结束行
if (buffer.read() != '"' || buffer.read() != '"') {
throw new DsonParseException("invalid text line, position: " + getPosition());
}
if (buffer.read() == '"') { // 超过3个引号
throw new DsonParseException("Illegal text block end: excessive quotes, position: " + getPosition());
}
buffer.unread();
return LineHead.END_OF_TEXT;
}
// 文本行必须'@'标记开始
if (c != '@') {
throw new DsonParseException("invalid text line, position: " + getPosition());
}
int head = buffer.read();
if (head < 0) {
throw new DsonParseException("invalid text line, position: " + getPosition());
}
LineHead lineHead = switch ((char) head) {
case DsonTexts.HEAD_APPEND_LINE -> LineHead.APPEND_LINE;
case DsonTexts.HEAD_APPEND -> LineHead.APPEND;
case DsonTexts.HEAD_SWITCH_MODE -> LineHead.SWITCH_MODE;
default -> throw new DsonParseException("invalid text line, position: " + getPosition());
};
// 如果未达文件尾，必须是空格或换行
c = buffer.read();
if (c < 0) {
buffer.unread();
} else if (c != ' ') {
throw spaceRequired(getPosition());
}
return lineHead;
}
buffer.unread(); // 空行
return LineHead.COMMENT;
}
private void doEscape(DsonCharStream buffer, StringBuilder sb) {
final int position = getPosition();
final int c = readEscapeChar(buffer, position);
switch (c) {
case '"' -> sb.append('"'); // 双引号字符串下，双引号需要转义
case '\\' -> sb.append('\\');
case 'b' -> sb.append('\b');
case 'f' -> sb.append('\f');
case 'n' -> sb.append('\n');
case 'r' -> sb.append('\r');
case 't' -> sb.append('\t');
case 'u' -> {
// unicode字符，char是2字节，固定编码为4个16进制数，从高到底
CharBuffer hexBuffer = this.hexBuffer;
hexBuffer.clear();
hexBuffer.write((char) readEscapeChar(buffer, position));
hexBuffer.write((char) readEscapeChar(buffer, position));
hexBuffer.write((char) readEscapeChar(buffer, position));
hexBuffer.write((char) readEscapeChar(buffer, position));
sb.append((char) Integer.parseInt(hexBuffer, 0, 4, 16));
}
default -> throw invalidEscapeSequence(c, position);
}
}
/** 读取下一个要转义的字符 */
private static int readEscapeChar(DsonCharStream buffer, int position) {
int c = buffer.read();
if (c >= 0) {
return c;
}
throw invalidEscapeSequence('\\', position);
}
// endregion
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