Doubt about writeEscapedString()

[glassfishrobot]

There are some doubts about writeEscapedString(). This method
char c = s.charAt; but then at some place it compares c < 0x10FFFF.

But this test trivially always true since char data type is in the range
0x0000 to 0xFFFF. Is the intention of the code to use s.codePointAt()?

Environment

All

Affected Versions

[1.0.4]

[glassfishrobot]

@glassfishrobot Commented
Reported by j4nbur53

[glassfishrobot]

@glassfishrobot Commented
Was assigned to kchung

[glassfishrobot]

@glassfishrobot Commented
j4nbur53 said:
Given that a Java String uses surrogate pairs for ranges above 0xFFFF, the code
somehow does what it should do, since the escaped codes 0x00-0x1F, 0x22 and 0x5c
are anyway in the lowest Unicode plane, not needing surrogate pairs.

[glassfishrobot]

@glassfishrobot Commented
robin479 said:
There is another subtle error near those lines: the character U+007F ("delete") and the character range U+0080 through U+009F ("C1 control codes") are control characters, which require escaping according to the JSON specification. The solution might be to escape JSON special characters U+0022 and U+005C (and optionally, U+002F), as well as characters for which java.lang.Character.isISOControl() is true.

Additionally, most JavaScript clients (erroneously) require the escaping of ALL line-terminating characters, which includes characters of the type java.lang.Character#LINE_SEPARATOR (currently only U+2028) and java.lang.Character#PARAGRAPH_SEPARATOR (currently only U+2029). Since JSON allows optional escaping of any character, the escaping of these problematic types of characters would be appreciated (see java.lang.Character.getType()).

Here's a replacement for writeEscapedString() which does all that:

void writeEscapedString(String string) {
        writeChar('"');
        int b = 0, len = string.length(); // b =: start of to-be-written characters (buffer)
        for (int i = b; i < len; i++) {
            final char c = string.charAt(i);
            if (c == '"' || c == '\\' || c == '/') {
writeString(string, b, i); b = i+1; // flush/reset buffer
writeChar('\\'); writeChar(c); // escape JSON special character
            } else if (c < ' ' || '~' < c) { // (outside printable ASCII range)
switch (Character.getType(c)) {
    case Character.CONTROL:
        final int idx = "\n\r\t\f\b".indexOf(c);
        if (0 <= idx) {
            writeString(string, b, i); b = i+1; // flush/reset buffer
            writeChar('\\'); writeChar("nrtfb".charAt(idx)); // escape well-known controls
            break; // from switch
        } // else: fall through
    case Character.LINE_SEPARATOR: // most JavaScript consumers require escaping...
    case Character.PARAGRAPH_SEPARATOR:  // ...of ALL line-terminating characters
        writeString(string, b, i); b = i+1; // flush/reset buffer
        final String hex = Integer.toHexString(c);
        writeString("\\u0000", 0, 6 - hex.length());
        writeString(hex);
}
            }
        }
        writeString(string, b, len); // flush buffer
        writeChar('"');
    }

[glassfishrobot]

@glassfishrobot Commented
This issue was imported from java.net JIRA JSONP-32

[glassfishrobot]

• Issue Imported From: https://github.com/javaee/jsonp/issues/32
• Original Issue Raised By:@glassfishrobot
• Original Issue Assigned To: @lukasj