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Config java code generation from defintion files for Java Vespa components.
// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.config.codegen;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* This class generates a tree of CNodes from a .def file.
*
* @author gjoranv
* @author hmusum
*/
public class DefParser {
public static final String DEFAULT_PACKAGE_PREFIX = "com.yahoo.";
static final Pattern commentPattern = Pattern.compile("^\\s*#+\\s*(.*?)\\s*$");
// TODO: Version is ignored, remove in Vespa 9
public static final Pattern versionPattern = Pattern.compile("^(version\\s*=\\s*)([0-9][0-9-]*)$");
// Namespace/package must start with a letter, since Java (Java language Spec, section 3.8) and C++ identifiers cannot start with a digit
public static final Pattern namespacePattern = getNamespacePattern("namespace");
public static final Pattern packagePattern = getNamespacePattern("package");
private static Pattern getNamespacePattern(String directive) {
return Pattern.compile("^(" + directive + "\\s*=\\s*)(([a-z][a-z0-9_]*)+([.][a-z][a-z0-9_]*)*)$");
}
private final BufferedReader reader;
private final String name;
private InnerCNode root = null;
private NormalizedDefinition normalizedDefinition = null;
private boolean systemErrEnabled = false;
private String comment = "";
/**
* Creates a new parser for a .def file with the given name and that can be accessed by the given reader.
*
* @param name The name of the .def file (not including the '.def' suffix).
* @param defReader A reader to the .def file.
*/
public DefParser(String name, Reader defReader) {
this.name = createName(name);
if (defReader == null) {
throw new CodegenRuntimeException("Must have a non-null reader for a .def file.");
}
if (defReader instanceof BufferedReader) {
reader = (BufferedReader)defReader;
} else {
reader = new BufferedReader(defReader);
}
}
void enableSystemErr() {
systemErrEnabled = true;
}
// If name contains namespace, return just name
private String createName(String name) {
if (name.contains(".")) {
return name.substring(name.lastIndexOf(".") + 1);
} else {
return name;
}
}
/**
* Parses the .def file upon the initial call. Subsequent calls returns the result from the initial call.
*
* @return A tree of CNodes representing this instance's .def file.
* @throws CodegenRuntimeException upon errors.
*/
public InnerCNode getTree() throws CodegenRuntimeException {
try {
if (root == null) parse();
} catch (DefParserException | IOException e) {
throw new CodegenRuntimeException("Error parsing or reading config definition." + e.getMessage(), e);
}
return root;
}
/**
* Parses the input from the reader and builds a tree of CNodes representing the .def file.
*
* @throws IOException upon reader errors.
* @throws DefParserException upon parsing errors.
*/
void parse() throws IOException, DefParserException {
root = new InnerCNode(name);
normalizedDefinition = new NormalizedDefinition();
String s;
List originalInput = new ArrayList<>();
while ((s = reader.readLine()) != null) {
originalInput.add(s);
}
reader.close();
// Parse and build tree of the original input
parseLines(root, originalInput, normalizedDefinition);
root.setMd5(normalizedDefinition.generateMd5Sum());
}
/**
* Parses one line from def-file and adds it to the tree.
* TODO: Method too long!
*
* @param root The root CNode in the tree.
* @param line A line from the def-file.
* @param nd A NormalizedDefinition object
* @throws IllegalArgumentException upon error in line.
*/
private void parseLine(CNode root, String line, NormalizedDefinition nd) throws IllegalArgumentException {
line = NormalizedDefinition.normalize(line);
line = line.trim();
if (line.length() == 0) {
// If having empty lines in between comments, that is logically a break in the comment too
if (!comment.isEmpty()) {
comment += "\n";
}
return;
}
Matcher commentMatch = commentPattern.matcher(line);
if (commentMatch.matches()) {
parseCommentLine(commentMatch);
return;
}
Matcher versionMatch = versionPattern.matcher(line);
if (versionMatch.matches()) {
printSystemErr("Warning: In config definition '" + name + "': version is deprecated and ignored, please remove, support will be removed in Vespa 9");
return;
}
Matcher namespaceMatcher = namespacePattern.matcher(line);
if (namespaceMatcher.matches()) {
parseNamespaceLine(namespaceMatcher.group(2));
nd.addNormalizedLine(line);
return;
}
Matcher packageMatcher = packagePattern.matcher(line);
if (packageMatcher.matches()) {
parsePackageLine(packageMatcher.group(2));
nd.addNormalizedLine(line);
return;
}
// Only add lines that are not namespace or comment lines
nd.addNormalizedLine(line);
DefLine defLine = new DefLine(line);
root.setLeaf(root.getName() + "." + defLine.getName(), defLine, comment);
comment = "";
}
private void parseCommentLine(Matcher commentMatch) {
if (!comment.isEmpty()) comment += "\n";
String addition = commentMatch.group(1);
if (addition.isEmpty()) addition = " ";
comment += addition;
}
private void parseNamespaceLine(String namespace) {
if (namespace.startsWith(DEFAULT_PACKAGE_PREFIX))
throw new IllegalArgumentException("Please use 'package' instead of 'namespace'.");
root.setNamespace(namespace);
root.setComment(comment);
comment = "";
}
private void parsePackageLine(String defPackage) {
root.setPackage(defPackage);
root.setComment(comment);
comment = "";
}
void parseLines(CNode root, List defLines, NormalizedDefinition nd) throws DefParserException {
DefParserException failure = null;
int lineNumber = 1;
for (String line : defLines) {
try {
parseLine(root, line, nd);
lineNumber++;
} catch (IllegalArgumentException e) {
String msg = "Error when parsing line " + lineNumber + ": " + line + "\n" + e.getMessage();
failure = new DefParserException(msg, e);
break;
}
}
if (failure != null) {
throw (failure);
}
}
public NormalizedDefinition getNormalizedDefinition() {
return normalizedDefinition;
}
/**
* For debugging - dump the tree from the given root to System.out.
*/
public static void dumpTree(CNode root, String indent) {
StringBuilder sb = new StringBuilder(indent + root.getName());
if (root instanceof LeafCNode) {
LeafCNode leaf = ((LeafCNode)root);
if (leaf.getDefaultValue() != null) {
sb.append(" = ").append(((LeafCNode)root).getDefaultValue().getValue());
}
}
System.out.println(sb);
if (!root.getComment().isEmpty()) {
String comment = root.getComment();
if (comment.contains("\n")) {
comment = comment.substring(0, comment.indexOf("\n")) + "...";
}
if (comment.length() > 60) {
comment = comment.substring(0, 57) + "...";
}
System.out.println(indent + " comment: " + comment);
}
CNode[] children = root.getChildren();
for (CNode c : children) {
dumpTree(c, indent + " ");
}
}
private void printSystemErr(String s) {
if (systemErrEnabled) System.err.println(s);
}
static class DefParserException extends Exception {
DefParserException(String s, Throwable cause) {
super(s, cause);
}
}
}
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