Make Error.safeToString convert control codes in strings to escapes.

Make Error.safeToString convert control codes in strings to escapes.

Converts values in the range 0x00 to 0x1f to escapes.
Escapes are either \xhh for most values, or \n, \r and \t for
NL, CR and TAB.

BUG= http://dartbug.com/11250
R=sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=26269

[Søren Gjesse, 2013-08-16 11:24:57]

lgtm

https://codereview.chromium.org/23116007/diff/1/sdk/lib/core/errors.dart
File sdk/lib/core/errors.dart (right):

https://codereview.chromium.org/23116007/diff/1/sdk/lib/core/errors.dart#newc...
sdk/lib/core/errors.dart:48: buffer.writeCharCode(codeUnit < 10 ? DIGIT_ZERO +
codeUnit
Align : with ?

https://codereview.chromium.org/23116007/diff/1/sdk/lib/core/errors.dart#newc...
sdk/lib/core/errors.dart:53: } else if (codeUnit == DOUBLE_QUOTE) {
Why is it that we want to escape double quote?

[Lasse Reichstein Nielsen, 2013-08-16 11:27:41]

https://codereview.chromium.org/23116007/diff/1/sdk/lib/core/errors.dart
File sdk/lib/core/errors.dart (right):

https://codereview.chromium.org/23116007/diff/1/sdk/lib/core/errors.dart#newc...
sdk/lib/core/errors.dart:53: } else if (codeUnit == DOUBLE_QUOTE) {
Readability - you can read the string and see where it ends, without confusing:
  "argle bargle", "glop glyph"
with two strings.

[Lasse Reichstein Nielsen, 2013-08-16 11:36:01]

Committed patchset #2 manually as r26269 (presubmit successful).

[srdjan, 2013-12-03 00:18:35]

https://codereview.chromium.org/23116007/diff/7001/sdk/lib/core/errors.dart
File sdk/lib/core/errors.dart (right):

https://codereview.chromium.org/23116007/diff/7001/sdk/lib/core/errors.dart#n...
sdk/lib/core/errors.dart:23: const int CARRIGE_RETURN = 0x0d;
Any reason why CARRIAGE_RETURN is misspelled?

[Lasse Reichstein Nielsen, 2013-12-03 08:50:27]

https://codereview.chromium.org/23116007/diff/7001/sdk/lib/core/errors.dart
File sdk/lib/core/errors.dart (right):

https://codereview.chromium.org/23116007/diff/7001/sdk/lib/core/errors.dart#n...
sdk/lib/core/errors.dart:23: const int CARRIGE_RETURN = 0x0d;
It's ... shorter?
It's spelled like it's pronounced?
Or are you looking for a *good* reason, in which case I can't help you :)

We REALLY should have character constants. Then we could avoid this silly
spelling stuff and just write #'\n'.