auto merge of #15238 : aochagavia/rust/json, r=alexcrichton

### Breaking changes:

* **Removed unnecessary `box` from enum variant (`Object(Box<Object>)` becomes `Object(Object)`)**
* **Deprecated `Encoder::str_encode`**

### Other changes:

* Tried to make the code more idiomatic
* Renamed the `wr` field of the `Encoder` and `PrettyEncoder` structs to `writer`
* Replaced some `from_utf8` by `from_utf8_owned` to avoid unnecessary allocations
* Removed unnecessary `unsafe` code
* Added `encode` and `decode` shortcut functions
* Implemented `FromStr` for `Json`
* Implemented `ToJson` for tuples of arity up to 12
* Fixed some details in the documentation

### Questions

* ~~The `encode` shortcut function does the same as the `Encoder::str_encode` function. It seems wrong to me that two functions do exactly the same. Should we deprecate `Encoder::str_encode`?~~
* ~~Do we really want the ToJson trait for tuples? At the moment we have it for (), (A, B), (A, B, C). I would like to remove them.~~
* ~~We are using `String` as key in the `TreeMap` representing a `Json` object. It would be better to use `&str`, but this would require to annotate lots of lifetimes. Is there any easy solution for this?~~
* There is a lot of duplicated code (`PrettyEncoder` copies about 50 lines from `Encoder`). In an OO language this could be solved very elegantly by using inheritance and overriding. What can we do here to reduce the amount of boilerplate?

[breaking-change]

diff --git a/src/libcollections/str.rs b/src/libcollections/str.rs
index b5424d1683fca566bba7a5296876c36c10113cea..10309adef20d9faafa8c8de2d610b66e30eeef9e 100644 (file)
--- a/src/libcollections/str.rs
+++ b/src/libcollections/str.rs
@@ -803,15 +803,9 @@ fn to_owned(&self) -> String {
     }
 
     /// Converts to a vector of `u16` encoded as UTF-16.
+    #[deprecated = "use `utf16_units` instead"]
     fn to_utf16(&self) -> Vec<u16> {
-        let me = self.as_slice();
-        let mut u = Vec::new();
-        for ch in me.chars() {
-            let mut buf = [0u16, ..2];
-            let n = ch.encode_utf16(buf /* as mut slice! */);
-            u.push_all(buf.slice_to(n));
-        }
-        u
+        self.as_slice().utf16_units().collect::<Vec<u16>>()
     }
 
     /// Given a string, make a new string with repeated copies of it.
@@ -1619,14 +1613,17 @@ fn test_utf16() {
 
         for p in pairs.iter() {
             let (s, u) = (*p).clone();
+            let s_as_utf16 = s.as_slice().utf16_units().collect::<Vec<u16>>();
+            let u_as_string = from_utf16(u.as_slice()).unwrap();
+
             assert!(is_utf16(u.as_slice()));
-            assert_eq!(s.to_utf16(), u);
+            assert_eq!(s_as_utf16, u);
 
-            assert_eq!(from_utf16(u.as_slice()).unwrap(), s);
+            assert_eq!(u_as_string, s);
             assert_eq!(from_utf16_lossy(u.as_slice()), s);
 
-            assert_eq!(from_utf16(s.to_utf16().as_slice()).unwrap(), s);
-            assert_eq!(from_utf16(u.as_slice()).unwrap().to_utf16(), u);
+            assert_eq!(from_utf16(s_as_utf16.as_slice()).unwrap(), s);
+            assert_eq!(u_as_string.as_slice().utf16_units().collect::<Vec<u16>>(), u);
         }
     }
 

diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index de23e04393be1bb99e22a3c66d2a0c79d94160e4..b336c57efa07228ad8d6d54518b3e6af46904079 100644 (file)
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -16,6 +16,7 @@
 
 use mem;
 use char;
+use char::Char;
 use clone::Clone;
 use cmp;
 use cmp::{PartialEq, Eq};
@@ -24,7 +25,7 @@
 use iter::{Filter, Map, Iterator};
 use iter::{DoubleEndedIterator, ExactSize};
 use iter::range;
-use num::Saturating;
+use num::{CheckedMul, Saturating};
 use option::{None, Option, Some};
 use raw::Repr;
 use slice::ImmutableVector;
@@ -557,6 +558,41 @@ fn next(&mut self) -> Option<&'a str> {
     }
 }
 
+/// External iterator for a string's UTF16 codeunits.
+/// Use with the `std::iter` module.
+#[deriving(Clone)]
+pub struct Utf16CodeUnits<'a> {
+    chars: Chars<'a>,
+    extra: u16
+}
+
+impl<'a> Iterator<u16> for Utf16CodeUnits<'a> {
+    #[inline]
+    fn next(&mut self) -> Option<u16> {
+        if self.extra != 0 {
+            let tmp = self.extra;
+            self.extra = 0;
+            return Some(tmp);
+        }
+
+        let mut buf = [0u16, ..2];
+        self.chars.next().map(|ch| {
+            let n = ch.encode_utf16(buf /* as mut slice! */);
+            if n == 2 { self.extra = buf[1]; }
+            buf[0]
+        })
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (uint, Option<uint>) {
+        let (low, high) = self.chars.size_hint();
+        // every char gets either one u16 or two u16,
+        // so this iterator is between 1 or 2 times as
+        // long as the underlying iterator.
+        (low, high.and_then(|n| n.checked_mul(&2)))
+    }
+}
+
 /*
 Section: Comparing strings
 */
@@ -1609,6 +1645,9 @@ pub trait StrSlice<'a> {
     /// and that it is not reallocated (e.g. by pushing to the
     /// string).
     fn as_ptr(&self) -> *const u8;
+
+    /// Return an iterator of `u16` over the string encoded as UTF-16.
+    fn utf16_units(&self) -> Utf16CodeUnits<'a>;
 }
 
 impl<'a> StrSlice<'a> for &'a str {
@@ -1957,6 +1996,11 @@ fn subslice_offset(&self, inner: &str) -> uint {
     fn as_ptr(&self) -> *const u8 {
         self.repr().data
     }
+
+    #[inline]
+    fn utf16_units(&self) -> Utf16CodeUnits<'a> {
+        Utf16CodeUnits{ chars: self.chars(), extra: 0}
+    }
 }
 
 impl<'a> Default for &'a str {

diff --git a/src/libnative/io/c_win32.rs b/src/libnative/io/c_win32.rs
index 7e58102d2418399b9d314242be84edcfc1d9e332..802526c91969524a9cfd4023466b7fce9f93aa72 100644 (file)
--- a/src/libnative/io/c_win32.rs
+++ b/src/libnative/io/c_win32.rs
@@ -70,6 +70,7 @@ pub fn CancelIoEx(hFile: libc::HANDLE,
 
 pub mod compat {
     use std::intrinsics::{atomic_store_relaxed, transmute};
+    use std::iter::Iterator;
     use libc::types::os::arch::extra::{LPCWSTR, HMODULE, LPCSTR, LPVOID};
 
     extern "system" {
@@ -82,7 +83,8 @@ pub mod compat {
     // layer (after it's loaded) shouldn't be any slower than a regular DLL
     // call.
     unsafe fn store_func(ptr: *mut uint, module: &str, symbol: &str, fallback: uint) {
-        let module = module.to_utf16().append_one(0);
+        let module: Vec<u16> = module.utf16_units().collect();
+        let module = module.append_one(0);
         symbol.with_c_str(|symbol| {
             let handle = GetModuleHandleW(module.as_ptr());
             let func: uint = transmute(GetProcAddress(handle, symbol));

diff --git a/src/libnative/io/file_win32.rs b/src/libnative/io/file_win32.rs
index 3195fa4f2d4ed301ef755c6838b312217ba1b356..98553603313404382aafa07a63d726c28ef9b1a6 100644 (file)
--- a/src/libnative/io/file_win32.rs
+++ b/src/libnative/io/file_win32.rs
@@ -255,7 +255,7 @@ fn drop(&mut self) {
 
 pub fn to_utf16(s: &CString) -> IoResult<Vec<u16>> {
     match s.as_str() {
-        Some(s) => Ok(s.to_utf16().append_one(0)),
+        Some(s) => Ok(s.utf16_units().collect::<Vec<u16>>().append_one(0)),
         None => Err(IoError {
             code: libc::ERROR_INVALID_NAME as uint,
             extra: 0,

diff --git a/src/libnative/io/process.rs b/src/libnative/io/process.rs
index b1c0d9a15069385582c6afdc2543330f8bf62a78..6fab73115cf9a5e2dcd1ddf7847f2796b4f44e4d 100644 (file)
--- a/src/libnative/io/process.rs
+++ b/src/libnative/io/process.rs
@@ -294,6 +294,8 @@ fn spawn_process_os(cfg: ProcessConfig,
     use libc::funcs::extra::msvcrt::get_osfhandle;
 
     use std::mem;
+    use std::iter::Iterator;
+    use std::str::StrSlice;
 
     if cfg.gid.is_some() || cfg.uid.is_some() {
         return Err(IoError {
@@ -328,7 +330,8 @@ fn spawn_process_os(cfg: ProcessConfig,
                         lpSecurityDescriptor: ptr::mut_null(),
                         bInheritHandle: 1,
                     };
-                    let filename = "NUL".to_utf16().append_one(0);
+                    let filename: Vec<u16> = "NUL".utf16_units().collect();
+                    let filename = filename.append_one(0);
                     *slot = libc::CreateFileW(filename.as_ptr(),
                                               access,
                                               libc::FILE_SHARE_READ |
@@ -371,7 +374,8 @@ fn spawn_process_os(cfg: ProcessConfig,
 
         with_envp(cfg.env, |envp| {
             with_dirp(cfg.cwd, |dirp| {
-                let mut cmd_str = cmd_str.to_utf16().append_one(0);
+                let mut cmd_str: Vec<u16> = cmd_str.as_slice().utf16_units().collect();
+                cmd_str = cmd_str.append_one(0);
                 let created = CreateProcessW(ptr::null(),
                                              cmd_str.as_mut_ptr(),
                                              ptr::mut_null(),
@@ -770,7 +774,7 @@ fn with_envp<T>(env: Option<&[(CString, CString)]>, cb: |*mut c_void| -> T) -> T
                 let kv = format!("{}={}",
                                  pair.ref0().as_str().unwrap(),
                                  pair.ref1().as_str().unwrap());
-                blk.push_all(kv.to_utf16().as_slice());
+                blk.extend(kv.as_slice().utf16_units());
                 blk.push(0);
             }
 
@@ -788,7 +792,9 @@ fn with_dirp<T>(d: Option<&CString>, cb: |*const u16| -> T) -> T {
       Some(dir) => {
           let dir_str = dir.as_str()
                            .expect("expected workingdirectory to be utf-8 encoded");
-          let dir_str = dir_str.to_utf16().append_one(0);
+          let dir_str: Vec<u16> = dir_str.utf16_units().collect();
+          let dir_str = dir_str.append_one(0);
+
           cb(dir_str.as_ptr())
       },
       None => cb(ptr::null())

diff --git a/src/librustdoc/flock.rs b/src/librustdoc/flock.rs
index cb2ebd15b3970ffc21733dc3672571bd1d479ba1..f07c016367634919387f6794fed522fd6a7673f9 100644 (file)
--- a/src/librustdoc/flock.rs
+++ b/src/librustdoc/flock.rs
@@ -162,7 +162,8 @@ pub struct Lock {
 
     impl Lock {
         pub fn new(p: &Path) -> Lock {
-            let p_16 = p.as_str().unwrap().to_utf16().append_one(0);
+            let p_16: Vec<u16> = p.as_str().unwrap().utf16_units().collect();
+            let p_16 = p_16.append_one(0);
             let handle = unsafe {
                 libc::CreateFileW(p_16.as_ptr(),
                                   libc::FILE_GENERIC_READ |

diff --git a/src/libstd/dynamic_lib.rs b/src/libstd/dynamic_lib.rs
index ec2cc67a60a16a53f92e7fd5c715e72cdf10516a..728875ce2601012f3d25b645de37fddae4212a36 100644 (file)
--- a/src/libstd/dynamic_lib.rs
+++ b/src/libstd/dynamic_lib.rs
@@ -281,19 +281,22 @@ fn dlsym(handle: *mut libc::c_void,
 #[cfg(target_os = "win32")]
 pub mod dl {
     use c_str::ToCStr;
+    use iter::Iterator;
     use libc;
     use os;
     use ptr;
     use result::{Ok, Err, Result};
-    use str::StrAllocating;
+    use str::StrSlice;
     use str;
     use string::String;
+    use vec::Vec;
 
     pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
         // Windows expects Unicode data
         let filename_cstr = filename.to_c_str();
         let filename_str = str::from_utf8(filename_cstr.as_bytes_no_nul()).unwrap();
-        let filename_str = filename_str.to_utf16().append_one(0);
+        let filename_str: Vec<u16> = filename_str.utf16_units().collect();
+        let filename_str = filename_str.append_one(0);
         LoadLibraryW(filename_str.as_ptr() as *const libc::c_void) as *mut u8
     }
 

diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index e0ed8cf667b38e185089866259d642fffe08f3ed..5201a81179144e2f7658f6c3d688ff101399c754 100644 (file)
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -365,7 +365,8 @@ pub fn getenv(n: &str) -> Option<String> {
     unsafe {
         with_env_lock(|| {
             use os::win32::{fill_utf16_buf_and_decode};
-            let n = n.to_utf16().append_one(0);
+            let n: Vec<u16> = n.utf16_units().collect();
+            let n = n.append_one(0);
             fill_utf16_buf_and_decode(|buf, sz| {
                 libc::GetEnvironmentVariableW(n.as_ptr(), buf, sz)
             })
@@ -411,8 +412,10 @@ fn _setenv(n: &str, v: &str) {
 
     #[cfg(windows)]
     fn _setenv(n: &str, v: &str) {
-        let n = n.to_utf16().append_one(0);
-        let v = v.to_utf16().append_one(0);
+        let n: Vec<u16> = n.utf16_units().collect();
+        let n = n.append_one(0);
+        let v: Vec<u16> = v.utf16_units().collect();
+        let v = v.append_one(0);
         unsafe {
             with_env_lock(|| {
                 libc::SetEnvironmentVariableW(n.as_ptr(), v.as_ptr());
@@ -437,7 +440,8 @@ fn _unsetenv(n: &str) {
 
     #[cfg(windows)]
     fn _unsetenv(n: &str) {
-        let n = n.to_utf16().append_one(0);
+        let n: Vec<u16> = n.utf16_units().collect();
+        let n = n.append_one(0);
         unsafe {
             with_env_lock(|| {
                 libc::SetEnvironmentVariableW(n.as_ptr(), ptr::null());
@@ -804,7 +808,7 @@ pub fn change_dir(p: &Path) -> bool {
     #[cfg(windows)]
     fn chdir(p: &Path) -> bool {
         let p = match p.as_str() {
-            Some(s) => s.to_utf16().append_one(0),
+            Some(s) => s.utf16_units().collect::<Vec<u16>>().append_one(0),
             None => return false,
         };
         unsafe {