302063 - Improve string API for error handling

Status: RESOLVED WORKSFORME

(Core :: XPCOM, enhancement)

Description

[Darin Fisher]

The string API makes error handling for things like out-of-memory difficult and
tedious.  The API encourages people not to do error checking, which can lead to
problems.  This is particularly the case when code uses BeginWriting to get
mutable access to the string's internal buffer.  People tend to write code that
calls SetLength followed by BeginWriting without checking that SetLength
succeeded.  The only way to do so is to call Length before calling BeginWriting.  

Another example is using Replace to modify the string.  It may be awkward to
compute what the length of the string should be after calling Replace, and so
people may avoid error checking.

This is somewhat related to bug 284219.

Comment 1

[Benjamin Smedberg]

We've done this by making the API infallible by default.