1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Immutable strings.

pub use core_foundation_sys::string::*;

use base::{CFIndexConvertible, TCFType};

use core_foundation_sys::base::{Boolean, CFIndex, CFRange};
use core_foundation_sys::base::{kCFAllocatorDefault, kCFAllocatorNull};
use std::borrow::Cow;
use std::fmt;
use std::str::{self, FromStr};
use std::ptr;
use std::ffi::CStr;


declare_TCFType!{
    /// An immutable string in one of a variety of encodings.
    CFString, CFStringRef
}
impl_TCFType!(CFString, CFStringRef, CFStringGetTypeID);

impl FromStr for CFString {
    type Err = ();

    /// See also CFString::new for a variant of this which does not return a Result
    #[inline]
    fn from_str(string: &str) -> Result<CFString, ()> {
        Ok(CFString::new(string))
    }
}

impl<'a> From<&'a str> for CFString {
    #[inline]
    fn from(string: &'a str) -> CFString {
        CFString::new(string)
    }
}

impl<'a> From<&'a CFString> for Cow<'a, str> {
    fn from(cf_str: &'a CFString) -> Cow<'a, str> {
        unsafe {
            // Do this without allocating if we can get away with it
            let c_string = CFStringGetCStringPtr(cf_str.0, kCFStringEncodingUTF8);
            if !c_string.is_null() {
                let c_str = CStr::from_ptr(c_string);
                Cow::Borrowed(str::from_utf8_unchecked(c_str.to_bytes()))
            } else {
                let char_len = cf_str.char_len();

                // First, ask how big the buffer ought to be.
                let mut bytes_required: CFIndex = 0;
                CFStringGetBytes(cf_str.0,
                                 CFRange { location: 0, length: char_len },
                                 kCFStringEncodingUTF8,
                                 0,
                                 false as Boolean,
                                 ptr::null_mut(),
                                 0,
                                 &mut bytes_required);

                // Then, allocate the buffer and actually copy.
                let mut buffer = vec![b'\x00'; bytes_required as usize];

                let mut bytes_used: CFIndex = 0;
                let chars_written = CFStringGetBytes(cf_str.0,
                                                     CFRange { location: 0, length: char_len },
                                                     kCFStringEncodingUTF8,
                                                     0,
                                                     false as Boolean,
                                                     buffer.as_mut_ptr(),
                                                     buffer.len().to_CFIndex(),
                                                     &mut bytes_used);
                assert_eq!(chars_written, char_len);

                // This is dangerous; we over-allocate and null-terminate the string (during
                // initialization).
                assert_eq!(bytes_used, buffer.len().to_CFIndex());
                Cow::Owned(String::from_utf8_unchecked(buffer))
            }
        }
    }
}

impl fmt::Display for CFString {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.write_str(&Cow::from(self))
    }
}

impl fmt::Debug for CFString {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "\"{}\"", self)
    }
}


impl CFString {
    /// Creates a new `CFString` instance from a Rust string.
    #[inline]
    pub fn new(string: &str) -> CFString {
        unsafe {
            let string_ref = CFStringCreateWithBytes(kCFAllocatorDefault,
                                                     string.as_ptr(),
                                                     string.len().to_CFIndex(),
                                                     kCFStringEncodingUTF8,
                                                     false as Boolean);
            CFString::wrap_under_create_rule(string_ref)
        }
    }

    /// Like `CFString::new`, but references a string that can be used as a backing store
    /// by virtue of being statically allocated.
    #[inline]
    pub fn from_static_string(string: &'static str) -> CFString {
        unsafe {
            let string_ref = CFStringCreateWithBytesNoCopy(kCFAllocatorDefault,
                                                           string.as_ptr(),
                                                           string.len().to_CFIndex(),
                                                           kCFStringEncodingUTF8,
                                                           false as Boolean,
                                                           kCFAllocatorNull);
            TCFType::wrap_under_create_rule(string_ref)
        }
    }

    /// Returns the number of characters in the string.
    #[inline]
    pub fn char_len(&self) -> CFIndex {
        unsafe {
            CFStringGetLength(self.0)
        }
    }
}

#[test]
fn string_and_back() {
    let original = "The quick brown fox jumped over the slow lazy dog.";
    let cfstr = CFString::from_static_string(original);
    let converted = cfstr.to_string();
    assert_eq!(converted, original);
}