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With inspiration from other libraries
/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.codegen.target;
import org.antlr.v4.codegen.CodeGenerator;
import org.antlr.v4.codegen.Target;
import org.antlr.v4.codegen.UnicodeEscapes;
import org.antlr.v4.parse.ANTLRParser;
import org.antlr.v4.tool.Grammar;
import org.antlr.v4.tool.ast.GrammarAST;
import org.stringtemplate.v4.ST;
import org.stringtemplate.v4.STGroup;
import org.stringtemplate.v4.StringRenderer;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;
/**
*
* @author Peter Boyer
*
* */
public class GoTarget extends Target {
private static final String[] goKeywords = {
"break", "default", "func", "interface", "select",
"case", "defer", "go", "map", "struct",
"chan", "else", "goto", "package", "switch",
"const", "fallthrough", "if", "range", "type",
"continue", "for", "import", "return", "var"
};
// predeclared identifiers https://golang.org/ref/spec#Predeclared_identifiers
private static final String[] goPredeclaredIdentifiers = {
"bool", "byte", "complex64", "complex128", "error", "float32", "float64",
"int", ",int8", "int16", "int32", "int64", "rune", "string",
"uint", "uint8", "uint16", "uint32", "uint64", "uintptr",
"true", "false", "iota", "nil",
"append", "cap", "close", "complex", "copy", "delete", "imag", "len",
"make", "new", "panic", "print", "println", "real", "recover"
};
// interface definition of RuleContext from runtime/Go/antlr/rule_context.go
private static final String[] goRuleContextInterfaceMethods = {
"Accept", "GetAltNumber", "GetBaseRuleContext", "GetChild", "GetChildCount",
"GetChildren", "GetInvokingState", "GetParent", "GetPayload", "GetRuleContext",
"GetRuleIndex", "GetSourceInterval", "GetText", "IsEmpty", "SetAltNumber",
"SetInvokingState", "SetParent", "String"
};
/** Avoid grammar symbols in this set to prevent conflicts in gen'd code. */
private final Set badWords = new HashSet(
goKeywords.length + goPredeclaredIdentifiers.length + goRuleContextInterfaceMethods.length + 3
);
private static final boolean DO_GOFMT = !Boolean.parseBoolean(System.getenv("ANTLR_GO_DISABLE_GOFMT"))
&& !Boolean.parseBoolean(System.getProperty("antlr.go.disable-gofmt"));
public GoTarget(CodeGenerator gen) {
super(gen, "Go");
}
@Override
public String getVersion() {
return "4.7.2";
}
public Set getBadWords() {
if (badWords.isEmpty()) {
addBadWords();
}
return badWords;
}
protected void addBadWords() {
badWords.addAll(Arrays.asList(goKeywords));
badWords.addAll(Arrays.asList(goPredeclaredIdentifiers));
badWords.addAll(Arrays.asList(goRuleContextInterfaceMethods));
badWords.add("rule");
badWords.add("parserRule");
badWords.add("action");
}
@Override
protected void genFile(Grammar g, ST outputFileST, String fileName) {
super.genFile(g, outputFileST, fileName);
if (DO_GOFMT && !fileName.startsWith(".") /* criterion taken from gofmt */ && fileName.endsWith(".go")) {
gofmt(new File(getCodeGenerator().tool.getOutputDirectory(g.fileName), fileName));
}
}
private void gofmt(File fileName) {
// Optimistically run gofmt. If this fails, it doesn't matter at this point. Wait for termination though,
// because "gofmt -w" uses ioutil.WriteFile internally, which means it literally writes in-place with O_TRUNC.
// That could result in a race. (Why oh why doesn't it do tmpfile + rename?)
try {
// TODO: need something like: String goExecutable = locateGo();
ProcessBuilder gofmtBuilder = new ProcessBuilder("gofmt", "-w", "-s", fileName.getPath());
gofmtBuilder.redirectErrorStream(true);
Process gofmt = gofmtBuilder.start();
InputStream stdout = gofmt.getInputStream();
// TODO(wjkohnen): simplify to `while (stdout.Read() > 1) {}`
byte[] buf = new byte[1 << 10];
for (int l = 0; l > -1; l = stdout.read(buf)) {
// There should not be any output that exceeds the implicit output buffer. In normal ops there should be
// zero output. In case there is output, blocking and therefore killing the process is acceptable. This
// drains the buffer anyway to play it safe.
// dirty debug (change -w above to -d):
// System.err.write(buf, 0, l);
}
gofmt.waitFor();
} catch (IOException e) {
// Probably gofmt not in $PATH, in any case ignore.
} catch (InterruptedException forward) {
Thread.currentThread().interrupt();
}
}
@Override
public String encodeIntAsCharEscape(int v) {
return Integer.toString(v);
}
@Override
public int getSerializedATNSegmentLimit() {
return 2 ^ 31;
}
@Override
public int getInlineTestSetWordSize() {
return 32;
}
@Override
protected boolean visibleGrammarSymbolCausesIssueInGeneratedCode(GrammarAST idNode) {
return getBadWords().contains(idNode.getText());
}
@Override
protected STGroup loadTemplates() {
STGroup result = super.loadTemplates();
result.registerRenderer(String.class, new JavaStringRenderer(), true);
return result;
}
public String getRecognizerFileName(boolean header) {
CodeGenerator gen = getCodeGenerator();
Grammar g = gen.g;
assert g!=null;
String name;
switch ( g.getType()) {
case ANTLRParser.PARSER:
name = g.name.endsWith("Parser") ? g.name.substring(0, g.name.length()-6) : g.name;
return name.toLowerCase()+"_parser.go";
case ANTLRParser.LEXER:
name = g.name.endsWith("Lexer") ? g.name.substring(0, g.name.length()-5) : g.name; // trim off "lexer"
return name.toLowerCase()+"_lexer.go";
case ANTLRParser.COMBINED:
return g.name.toLowerCase()+"_parser.go";
default :
return "INVALID_FILE_NAME";
}
}
/** A given grammar T, return the listener name such as
* TListener.java, if we're using the Java target.
*/
public String getListenerFileName(boolean header) {
CodeGenerator gen = getCodeGenerator();
Grammar g = gen.g;
assert g.name != null;
return g.name.toLowerCase()+"_listener.go";
}
/** A given grammar T, return the visitor name such as
* TVisitor.java, if we're using the Java target.
*/
public String getVisitorFileName(boolean header) {
CodeGenerator gen = getCodeGenerator();
Grammar g = gen.g;
assert g.name != null;
return g.name.toLowerCase()+"_visitor.go";
}
/** A given grammar T, return a blank listener implementation
* such as TBaseListener.java, if we're using the Java target.
*/
public String getBaseListenerFileName(boolean header) {
CodeGenerator gen = getCodeGenerator();
Grammar g = gen.g;
assert g.name != null;
return g.name.toLowerCase()+"_base_listener.go";
}
/** A given grammar T, return a blank listener implementation
* such as TBaseListener.java, if we're using the Java target.
*/
public String getBaseVisitorFileName(boolean header) {
CodeGenerator gen = getCodeGenerator();
Grammar g = gen.g;
assert g.name != null;
return g.name.toLowerCase()+"_base_visitor.go";
}
protected static class JavaStringRenderer extends StringRenderer {
@Override
public String toString(Object o, String formatString, Locale locale) {
if ("java-escape".equals(formatString)) {
// 5C is the hex code for the \ itself
return ((String)o).replace("\\u", "\\u005Cu");
}
return super.toString(o, formatString, locale);
}
}
@Override
protected void appendUnicodeEscapedCodePoint(int codePoint, StringBuilder sb) {
// Go and Python share the same escaping style.
UnicodeEscapes.appendPythonStyleEscapedCodePoint(codePoint, sb);
}
}