ErrorListener that collect and enhance the errors send by the CQL lexer and parser.
*/
templateErrorCollector instance to collect the syntax errors associated to the specified CQL
* query.
*
* @param query the CQL query that will be parsed
*/
error_collector(const sstring_view& query) : _query(query) {}
/**
* Format and throw a new \c exceptions::syntax_exception.
*/
[[noreturn]] virtual void syntax_error(RecognizerType& recognizer, ANTLR_UINT8** token_names, ExceptionBaseType* ex) override {
auto hdr = get_error_header(ex);
auto msg = get_error_message(recognizer, ex, token_names);
std::stringstream result;
result << hdr << ' ' << msg;
#if 0
if (recognizer instanceof Parser)
appendQuerySnippet((Parser) recognizer, builder);
#endif
throw exceptions::syntax_exception(result.str());
}
/**
* Throw a new \c exceptions::syntax_exception.
*/
[[noreturn]] virtual void syntax_error(RecognizerType&, const sstring& msg) override {
throw exceptions::syntax_exception(msg);
}
private:
std::string get_error_header(ExceptionBaseType* ex) {
std::stringstream result;
result << "line " << ex->get_line() << ":" << ex->get_charPositionInLine();
return result.str();
}
std::string get_error_message(RecognizerType& recognizer, ExceptionBaseType* ex, ANTLR_UINT8** token_names)
{
using namespace antlr3;
std::stringstream msg;
switch (ex->getType()) {
case ExceptionType::UNWANTED_TOKEN_EXCEPTION: {
msg << "extraneous input " << get_token_error_display(recognizer, ex->get_token());
if (token_names != nullptr) {
std::string token_name;
if (recognizer.is_eof_token(ex->get_expecting())) {
token_name = "EOF";
} else {
token_name = reinterpret_castStringBuilder used to build the error message
*/
private void appendQuerySnippet(Parser parser, StringBuilder builder)
{
TokenStream tokenStream = parser.getTokenStream();
int index = tokenStream.index();
int size = tokenStream.size();
Token from = tokenStream.get(getSnippetFirstTokenIndex(index));
Token to = tokenStream.get(getSnippetLastTokenIndex(index, size));
Token offending = tokenStream.get(getOffendingTokenIndex(index, size));
appendSnippet(builder, from, to, offending);
}
/**
* Appends a query snippet to the message to help the user to understand the problem.
*
* @param from the first token to include within the snippet
* @param to the last token to include within the snippet
* @param offending the token which is responsible for the error
*/
final void appendSnippet(StringBuilder builder,
Token from,
Token to,
Token offending)
{
if (!areTokensValid(from, to, offending))
return;
String[] lines = query.split("\n");
boolean includeQueryStart = (from.getLine() == 1) && (from.getCharPositionInLine() == 0);
boolean includeQueryEnd = (to.getLine() == lines.length)
&& (getLastCharPositionInLine(to) == lines[lines.length - 1].length());
builder.append(" (");
if (!includeQueryStart)
builder.append("...");
String toLine = lines[lineIndex(to)];
int toEnd = getLastCharPositionInLine(to);
lines[lineIndex(to)] = toEnd >= toLine.length() ? toLine : toLine.substring(0, toEnd);
lines[lineIndex(offending)] = highlightToken(lines[lineIndex(offending)], offending);
lines[lineIndex(from)] = lines[lineIndex(from)].substring(from.getCharPositionInLine());
for (int i = lineIndex(from), m = lineIndex(to); i <= m; i++)
builder.append(lines[i]);
if (!includeQueryEnd)
builder.append("...");
builder.append(")");
}
/**
* Checks if the specified tokens are valid.
*
* @param tokens the tokens to check
* @return true if all the specified tokens are valid ones,
* false otherwise.
*/
private static boolean areTokensValid(Token... tokens)
{
for (Token token : tokens)
{
if (!isTokenValid(token))
return false;
}
return true;
}
/**
* Checks that the specified token is valid.
*
* @param token the token to check
* @return true if it is considered as valid, false otherwise.
*/
private static boolean isTokenValid(Token token)
{
return token.getLine() > 0 && token.getCharPositionInLine() >= 0;
}
/**
* Returns the index of the offending token. In the case where the offending token is an extra
* character at the end, the index returned by the TokenStream might be after the last token.
* To avoid that problem we need to make sure that the index of the offending token is a valid index
* (one for which a token exist).
TokenStream
* @param size the TokenStream size
* @return the valid index of the offending token
*/
private static int getOffendingTokenIndex(int index, int size)
{
return Math.min(index, size - 1);
}
/**
* Puts the specified token within square brackets.
*
* @param line the line containing the token
* @param token the token to put within square brackets
*/
private static String highlightToken(String line, Token token)
{
String newLine = insertChar(line, getLastCharPositionInLine(token), ']');
return insertChar(newLine, token.getCharPositionInLine(), '[');
}
/**
* Returns the index of the last character relative to the beginning of the line 0..n-1
*
* @param token the token
* @return the index of the last character relative to the beginning of the line 0..n-1
*/
private static int getLastCharPositionInLine(Token token)
{
return token.getCharPositionInLine() + getLength(token);
}
/**
* Return the token length.
*
* @param token the token
* @return the token length
*/
private static int getLength(Token token)
{
return token.getText().length();
}
/**
* Inserts a character at a given position within a String.
*
* @param s the String in which the character must be inserted
* @param index the position where the character must be inserted
* @param c the character to insert
* @return the modified String
*/
private static String insertChar(String s, int index, char c)
{
return new StringBuilder().append(s.substring(0, index))
.append(c)
.append(s.substring(index))
.toString();
}
/**
* Returns the index of the line number on which this token was matched; index=0..n-1
*
* @param token the token
* @return the index of the line number on which this token was matched; index=0..n-1
*/
private static int lineIndex(Token token)
{
return token.getLine() - 1;
}
/**
* Returns the index of the last token which is part of the snippet.
*
* @param index the index of the token causing the error
* @param size the total number of tokens
* @return the index of the last token which is part of the snippet.
*/
private static int getSnippetLastTokenIndex(int index, int size)
{
return Math.min(size - 1, index + LAST_TOKEN_OFFSET);
}
/**
* Returns the index of the first token which is part of the snippet.
*
* @param index the index of the token causing the error
* @return the index of the first token which is part of the snippet.
*/
private static int getSnippetFirstTokenIndex(int index)
{
return Math.max(0, index - FIRST_TOKEN_OFFSET);
}
#endif
};
template