JS_FlattenString 编辑

This article covers features introduced in SpiderMonkey 1.8.5

Flattens a string. This makes getting the characters of the string infallible.

Syntax

JSFlatString *
JS_FlattenString(JSContext *cx, JSString *str);

Description

JS_FlattenString flattens a string str and returns a pointer to JSFlatString.

To catch errors, an opaque JSFlatString type is returned.

If a JSString is known to be flat, you can use JS_ASSERT_STRING_IS_FLAT to make a debug-checked cast. Example:

// In a fallible situation

JSFlatString *fstr = JS_FlattenString(cx, str);
if (!fstr)
  return false;
JS_ASSERT(fstr == JS_ASSERT_STRING_IS_FLAT(str));

// in an infallible situation, for the same 'str'

const jschar *chars = JS_GetFlatStringChars(fstr)
JS_ASSERT(chars);

See Also

• MXR ID Search for JS_FlattenString
• JS_ASSERT_STRING_IS_FLAT
• JS_FORGET_STRING_FLATNESS
• bug 609440