Ensure that |aString| is encoded in UTF-8. If not,
convert to UTF-8 assuming it’s encoded in |aCharset|
and return the converted string in UTF-8.
| aString | a string to ensure its UTF8ness |
| aCharset | the charset to convert from if |aString| is not in UTF-8 |
| aSkipCheck | determines whether or not to skip 'ASCIIness' and 'UTF8ness' check. Set this to PR_TRUE only if you suspect that aString can be mistaken for ASCII / UTF-8 but is actually NOT in ASCII / UTF-8 so that aString has to go through the conversion. skipping ASCIIness/UTF8ness check. The most common case is the input is in 7bit non-ASCII charsets like ISO-2022-JP, HZ or UTF-7 (in its original form or a modified form used in IMAP folder names). |
| aAllowSubstitution | when true, allow the decoder to substitute invalid input sequences by replacement characters (defaults to true) |
| the converted string in UTF-8. @throws NS_ERROR_UCONV_NOCONV when there is no decoder for aCharset or error code of nsIUnicodeDecoder in case of conversion failure |
Ensure that |aSpec| (after URL-unescaping it) is encoded in UTF-8.
If not, convert it to UTF-8, assuming it’s encoded in |aCharset|,
and return the result.
Make sure that all characters outside US-ASCII in your input spec are url-escaped if your spec is not in UTF-8 (before url-escaping) because the presence of non-ASCII characters is blindly regarded as an indication that your input spec is in unescaped UTF-8 and it will be returned without further processing. No valid spec going around in Mozilla code would break this assumption.
XXX The above may change in the future depending on the usage pattern. #### Parameters ####
| aSpec | an url-escaped URI spec to ensure its UTF8ness |
| aCharset | the charset to convert from if |aSpec| is not in UTF-8 |
| the converted spec in UTF-8. @throws NS_ERROR_UCONV_NOCONV when there is no decoder for aCharset or error code of nsIUnicodeDecoder in case of conversion failure |