Add support for multiline strings

protostuff-parser/src/main/antlr4/io/protostuff/compiler/parser/ProtoLexer.g4

@@ -182,6 +182,10 @@ IDENT
     :   (ALPHA | UNDERSCORE) (ALPHA | DIGIT | UNDERSCORE)*
     ;
 STRING_VALUE
+    : BACKTICK_STRING
+    | TRIPLE_DOUBLE_QUOTE_STRING
+    ;
+STRING_NAME
     : DOUBLE_QUOTE_STRING
     | SINGLE_QUOTE_STRING
     ;
@@ -202,6 +206,17 @@ fragment DOUBLE_QUOTE_STRING
 fragment SINGLE_QUOTE_STRING
     : '\'' ( ESC_SEQ | ~('\\' | '\'' | '\r' | '\n') )* '\''
     ;
+fragment BACKTICK_STRING
+    : '`' ( ESC_SEQ | ~('\\' | '`') )* '`'
+    ;
+fragment TRIPLE_DOUBLE_QUOTE_STRING
+    : '"""' TDQ_STRING_CHAR*? '"""'
+    ;
+fragment TDQ_STRING_CHAR
+    :   ~["\\]
+    |   '"' { !(_input.LA(1) == '"' && _input.LA(2) == '"') }?
+    |   ESC_SEQ
+    ;
 fragment EXPONENT
     : (FLOAT_LIT|DEC_VALUE) EXP DEC_VALUE
     ;
@@ -212,7 +227,7 @@ fragment FLOAT_LIT
 fragment INF
     : 'inf'
     ;
-fragment NAN 
+fragment NAN
     : 'nan'
     ;
 fragment EXP
@@ -247,7 +262,7 @@ fragment UNDERSCORE
     : '_'
     ;
 fragment ESC_SEQ
-    :   '\\' ('a'|'v'|'b'|'t'|'n'|'f'|'r'|'?'|'"'|'\''|'\\')
+    :   '\\' ('a'|'v'|'b'|'t'|'n'|'f'|'r'|'?'|'"'|'\''|'\\'|'`')
     |   '\\' ('x'|'X') HEX_DIGIT HEX_DIGIT
     |   UNICODE_ESC
     |   OCTAL_ESC
@@ -269,4 +284,4 @@ fragment UNICODE_ESC
  */
 ERRCHAR
 	:	.	-> channel(HIDDEN)
-	;
+	;

protostuff-parser/src/main/antlr4/io/protostuff/compiler/parser/ProtoParser.g4

@@ -20,7 +20,7 @@ syntaxStatement
     : SYNTAX ASSIGN syntaxName SEMICOLON
     ;
 syntaxName
-    : STRING_VALUE
+    : STRING_NAME
     ;
 packageStatement
     : PACKAGE packageName SEMICOLON
@@ -32,7 +32,7 @@ importStatement
     : IMPORT PUBLIC? fileReference SEMICOLON
     ;
 fileReference
-    : STRING_VALUE
+    : STRING_NAME
     ;
 optionEntry
     : OPTION option SEMICOLON
@@ -160,7 +160,7 @@ reservedFieldNames
     : RESERVED reservedFieldName (COMMA reservedFieldName)* SEMICOLON
     ;
 reservedFieldName
-    : STRING_VALUE
+    : STRING_NAME
     ;
 field
     : fieldModifier? typeReference fieldName ASSIGN tag fieldOptions? SEMICOLON
@@ -211,6 +211,7 @@ optionValue
     : INTEGER_VALUE
     | FLOAT_VALUE
     | BOOLEAN_VALUE
+    | STRING_NAME
     | STRING_VALUE
     | IDENT
     | textFormat
@@ -230,6 +231,7 @@ textFormatOptionValue
     : INTEGER_VALUE
     | FLOAT_VALUE
     | BOOLEAN_VALUE
+    | STRING_NAME
     | STRING_VALUE
     | IDENT
     ;
@@ -276,4 +278,4 @@ ident
     | BOOL
     | STRING
     | BYTES
-    ;
+    ;

protostuff-parser/src/main/java/io/protostuff/compiler/model/DynamicMessage.java

@@ -148,7 +148,7 @@ private void merge(DynamicMessage message) {
     private Key createKey(String fieldName) {
         Key key;
         if (fieldName.startsWith("(")) {
-            String name = Util.removeFirstAndLastChar(fieldName);
+            String name = Util.trimStringName(fieldName);
             if (name.startsWith(".")) {
                 name = name.substring(1);
             }

protostuff-parser/src/main/java/io/protostuff/compiler/parser/MessageParseListener.java

@@ -72,7 +72,7 @@ public void exitReservedFieldNames(ProtoParser.ReservedFieldNamesContext ctx) {
         UserType userType = context.peek(UserType.class);
         for (ProtoParser.ReservedFieldNameContext fieldNameContext : ctx.reservedFieldName()) {
             String fieldName = fieldNameContext.getText();
-            fieldName = Util.removeFirstAndLastChar(fieldName);
+            fieldName = Util.trimStringName(fieldName);
             userType.addReservedFieldName(fieldName);
         }
     }

protostuff-parser/src/main/java/io/protostuff/compiler/parser/OptionParseListener.java

@@ -52,10 +52,14 @@ private DynamicMessage.Value getOptionValue(ProtoParser.OptionValueContext optio
         } else if (optionValueContext.INTEGER_VALUE() != null) {
             String text = optionValueContext.INTEGER_VALUE().getText();
             optionValue = parseInteger(sourceCodeLocation, text);
+        } else if (optionValueContext.STRING_NAME() != null) {
+            String text = optionValueContext.STRING_NAME().getText();
+            // TODO: unescape
+            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.trimStringName(text));
         } else if (optionValueContext.STRING_VALUE() != null) {
             String text = optionValueContext.STRING_VALUE().getText();
             // TODO: unescape
-            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.removeFirstAndLastChar(text));
+            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.trimStringValue(text));
         } else if (optionValueContext.IDENT() != null) {
             String text = optionValueContext.IDENT().getText();
             optionValue = DynamicMessage.Value.createEnum(sourceCodeLocation, text);
@@ -142,10 +146,14 @@ private DynamicMessage.Value getTextFormatOptionValue(ProtoParser.TextFormatEntr
         } else if (ctx.textFormatOptionValue().INTEGER_VALUE() != null) {
             String text = ctx.textFormatOptionValue().INTEGER_VALUE().getText();
             optionValue = parseInteger(sourceCodeLocation, text);
+        } else if (ctx.textFormatOptionValue().STRING_NAME() != null) {
+            String text = ctx.textFormatOptionValue().STRING_NAME().getText();
+            // TODO: unescape
+            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.trimStringName(text));
         } else if (ctx.textFormatOptionValue().STRING_VALUE() != null) {
             String text = ctx.textFormatOptionValue().STRING_VALUE().getText();
             // TODO: unescape
-            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.removeFirstAndLastChar(text));
+            optionValue = DynamicMessage.Value.createString(sourceCodeLocation, Util.trimStringValue(text));
         } else if (ctx.textFormatOptionValue().IDENT() != null) {
             String text = ctx.textFormatOptionValue().IDENT().getText();
             optionValue = DynamicMessage.Value.createEnum(sourceCodeLocation, text);

protostuff-parser/src/main/java/io/protostuff/compiler/parser/ProtoParseListener.java

@@ -74,7 +74,7 @@ private boolean isCommentBlockOwner(Token token) {
     public void exitSyntaxStatement(ProtoParser.SyntaxStatementContext ctx) {
         Proto proto = context.peek(Proto.class);
         String text = ctx.syntaxName().getText();
-        String value = Util.removeFirstAndLastChar(text);
+        String value = Util.trimStringName(text);
         Syntax syntax = new Syntax(proto, value);
         syntax.setSourceCodeLocation(getSourceCodeLocation(ctx));
         proto.setSyntax(syntax);
@@ -93,7 +93,7 @@ public void exitPackageStatement(ProtoParser.PackageStatementContext ctx) {
     public void exitImportStatement(ProtoParser.ImportStatementContext ctx) {
         Proto proto = context.peek(Proto.class);
         String text = ctx.fileReference().getText();
-        String fileName = Util.removeFirstAndLastChar(text);
+        String fileName = Util.trimStringName(text);
         Import anImport = new Import(proto, fileName, ctx.PUBLIC() != null);
         anImport.setSourceCodeLocation(getSourceCodeLocation(ctx));
         proto.addImport(anImport);

protostuff-parser/src/main/java/io/protostuff/compiler/parser/Util.java

@@ -1,6 +1,7 @@
 package io.protostuff.compiler.parser;
 
 import com.google.common.base.Preconditions;
+
 import javax.annotation.ParametersAreNonnullByDefault;
 
 /**
@@ -26,13 +27,42 @@ private Util() {
      * @param text given string
      *
      * @return substring of given string - without first and last characters
+     * @deprecated replaced by {@link #trimStringName(String)}
      */
     public static String removeFirstAndLastChar(String text) {
+        return trimStringName(text);
+    }
+
+    /**
+     * Remove first and last character from given string name and return result.
+     *
+     * @param text given string
+     *
+     * @return substring of given string - without first and last characters
+     */
+    public static String trimStringName(String text) {
         Preconditions.checkNotNull(text, "text can not be null");
         int n = text.length();
         return text.substring(1, n - 1);
     }
 
+    /**
+     * Remove first and last character from given string value and return result.
+     *
+     * A string value can be wrapped by either a backtick, `, or triple double
+     * quote, """.
+     *
+     * @param text given string value
+     *
+     * @return substring of given string - without first and last characters
+     */
+    public static String trimStringValue(String text) {
+        Preconditions.checkNotNull(text, "text can not be null");
+        int size = text.startsWith("`") ? 1 : 3;
+        int n = text.length();
+        return text.substring(size, n - size);
+    }
+
     /**
      * Returns file name by given absolute or relative file location.
      * TODO: remove unused?

protostuff-parser/src/test/java/io/protostuff/compiler/parser/UtilTest.java

@@ -2,7 +2,8 @@
 
 import org.junit.jupiter.api.Test;
 
-import static io.protostuff.compiler.parser.Util.removeFirstAndLastChar;
+import static io.protostuff.compiler.parser.Util.trimStringName;
+import static io.protostuff.compiler.parser.Util.trimStringValue;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 /**
@@ -11,8 +12,13 @@
 public class UtilTest {
 
     @Test
-    public void testRemoveQuotes_expected() throws Exception {
-        assertEquals("abc", removeFirstAndLastChar("\"abc\""));
+    public void testTrimStringName_expected() throws Exception {
+        assertEquals("abc", trimStringName("\"abc\""));
     }
 
-}
+    @Test
+    public void testTrimStringValue_expected() throws Exception {
+        assertEquals("abc", trimStringValue("`abc`"));
+        assertEquals("abc", trimStringValue("\"\"\"abc\"\"\""));
+    }
+}

protostuff-parser/src/test/resources/protobuf_unittest/unittest.proto

@@ -161,6 +161,8 @@ message TestAllTypes {
     optional bool default_bool = 73 [default = true];
     optional string default_string = 74 [default = "hello"];
     optional bytes default_bytes = 75 [default = "world"];
+    optional string default_m_string = 76 [default = `hello
+world`];
 
     optional NestedEnum default_nested_enum = 81 [default = BAR];
     optional ForeignEnum default_foreign_enum = 82 [default = FOREIGN_BAR];
@@ -560,6 +562,9 @@ message TestExtremeDefaultValues {
     optional string string_piece_with_zero = 25 [ctype = STRING_PIECE, default = "ab\000c"];
     optional string cord_with_zero = 26 [ctype = CORD, default = "12\0003"];
     optional string replacement_string = 27 [default = "${unknown}"];
+    optional string tick_multiline_string = 28 [default=`backtick
+multiline
+default`];
 }
 
 message SparseEnumMessage {