std: Stabilize the std::str module

This commit starts out by consolidating all `str` extension traits into one
`StrExt` trait to be included in the prelude. This means that
`UnicodeStrPrelude`, `StrPrelude`, and `StrAllocating` have all been merged into
one `StrExt` exported by the standard library. Some functionality is currently
duplicated with the `StrExt` present in libcore.

This commit also currently avoids any methods which require any form of pattern
to operate. These functions will be stabilized via a separate RFC.

Next, stability of methods and structures are as follows:

Stable

* from_utf8_unchecked
* CowString - after moving to std::string
* StrExt::as_bytes
* StrExt::as_ptr
* StrExt::bytes/Bytes - also made a struct instead of a typedef
* StrExt::char_indices/CharIndices - CharOffsets was renamed
* StrExt::chars/Chars
* StrExt::is_empty
* StrExt::len
* StrExt::lines/Lines
* StrExt::lines_any/LinesAny
* StrExt::slice_unchecked
* StrExt::trim
* StrExt::trim_left
* StrExt::trim_right
* StrExt::words/Words - also made a struct instead of a typedef

Unstable

* from_utf8 - the error type was changed to a `Result`, but the error type has
              yet to prove itself
* from_c_str - this function will be handled by the c_str RFC
* FromStr - this trait will have an associated error type eventually
* StrExt::escape_default - needs iterators at least, unsure if it should make
                           the cut
* StrExt::escape_unicode - needs iterators at least, unsure if it should make
                           the cut
* StrExt::slice_chars - this function has yet to prove itself
* StrExt::slice_shift_char - awaiting conventions about slicing and shifting
* StrExt::graphemes/Graphemes - this functionality may only be in libunicode
* StrExt::grapheme_indices/GraphemeIndices - this functionality may only be in
                                             libunicode
* StrExt::width - this functionality may only be in libunicode
* StrExt::utf16_units - this functionality may only be in libunicode
* StrExt::nfd_chars - this functionality may only be in libunicode
* StrExt::nfkd_chars - this functionality may only be in libunicode
* StrExt::nfc_chars - this functionality may only be in libunicode
* StrExt::nfkc_chars - this functionality may only be in libunicode
* StrExt::is_char_boundary - naming is uncertain with container conventions
* StrExt::char_range_at - naming is uncertain with container conventions
* StrExt::char_range_at_reverse - naming is uncertain with container conventions
* StrExt::char_at - naming is uncertain with container conventions
* StrExt::char_at_reverse - naming is uncertain with container conventions
* StrVector::concat - this functionality may be replaced with iterators, but
                      it's not certain at this time
* StrVector::connect - as with concat, may be deprecated in favor of iterators

Deprecated

* StrAllocating and UnicodeStrPrelude have been merged into StrExit
* eq_slice - compiler implementation detail
* from_str - use the inherent parse() method
* is_utf8 - call from_utf8 instead
* replace - call the method instead
* truncate_utf16_at_nul - this is an implementation detail of windows and does
                          not need to be exposed.
* utf8_char_width - moved to libunicode
* utf16_items - moved to libunicode
* is_utf16 - moved to libunicode
* Utf16Items - moved to libunicode
* Utf16Item - moved to libunicode
* Utf16Encoder - moved to libunicode
* AnyLines - renamed to LinesAny and made a struct
* SendStr - use CowString<'static> instead
* str::raw - all functionality is deprecated
* StrExt::into_string - call to_string() instead
* StrExt::repeat - use iterators instead
* StrExt::char_len - use .chars().count() instead
* StrExt::is_alphanumeric - use .chars().all(..)
* StrExt::is_whitespace - use .chars().all(..)

Pending deprecation -- while slicing syntax is being worked out, these methods
are all #[unstable]

* Str - while currently used for generic programming, this trait will be
        replaced with one of [], deref coercions, or a generic conversion trait.
* StrExt::slice - use slicing syntax instead
* StrExt::slice_to - use slicing syntax instead
* StrExt::slice_from - use slicing syntax instead
* StrExt::lev_distance - deprecated with no replacement

Awaiting stabilization due to patterns and/or matching

* StrExt::contains
* StrExt::contains_char
* StrExt::split
* StrExt::splitn
* StrExt::split_terminator
* StrExt::rsplitn
* StrExt::match_indices
* StrExt::split_str
* StrExt::starts_with
* StrExt::ends_with
* StrExt::trim_chars
* StrExt::trim_left_chars
* StrExt::trim_right_chars
* StrExt::find
* StrExt::rfind
* StrExt::find_str
* StrExt::subslice_offset

1 files changed, 38 insertions, 1 deletions

diff --git a/src/libstd/sys/windows/os.rs b/src/libstd/sys/windows/os.rs
index e2220b7b67b..e1016048e58 100644
--- a/src/libstd/sys/windows/os.rs
+++ b/src/libstd/sys/windows/os.rs
@@ -31,6 +31,16 @@ use libc::types::os::arch::extra::DWORD;
 
 const BUF_BYTES : uint = 2048u;
 
+/// Return a slice of `v` ending at (and not including) the first NUL
+/// (0).
+pub fn truncate_utf16_at_nul<'a>(v: &'a [u16]) -> &'a [u16] {
+    match v.iter().position(|c| *c == 0) {
+        // don't include the 0
+        Some(i) => v[..i],
+        None => v
+    }
+}
+
 pub fn errno() -> uint {
     use libc::types::os::arch::extra::DWORD;
 
@@ -87,7 +97,7 @@ pub fn error_string(errnum: i32) -> String {
             return format!("OS Error {} (FormatMessageW() returned error {})", errnum, fm_err);
         }
 
-        let msg = String::from_utf16(::str::truncate_utf16_at_nul(&buf));
+        let msg = String::from_utf16(truncate_utf16_at_nul(&buf));
         match msg {
             Some(msg) => format!("OS Error {}: {}", errnum, msg),
             None => format!("OS Error {} (FormatMessageW() returned invalid UTF-16)", errnum),
@@ -294,3 +304,30 @@ pub fn page_size() -> uint {
         return info.dwPageSize as uint;
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::truncate_utf16_at_nul;
+
+    #[test]
+    fn test_truncate_utf16_at_nul() {
+        let v = [];
+        let b: &[u16] = &[];
+        assert_eq!(truncate_utf16_at_nul(&v), b);
+
+        let v = [0, 2, 3];
+        assert_eq!(truncate_utf16_at_nul(&v), b);
+
+        let v = [1, 0, 3];
+        let b: &[u16] = &[1];
+        assert_eq!(truncate_utf16_at_nul(&v), b);
+
+        let v = [1, 2, 0];
+        let b: &[u16] = &[1, 2];
+        assert_eq!(truncate_utf16_at_nul(&v), b);
+
+        let v = [1, 2, 3];
+        let b: &[u16] = &[1, 2, 3];
+        assert_eq!(truncate_utf16_at_nul(&v), b);
+    }
+}