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
151
152
153
154
155
156
157
158
159
160
161
162
163
164

//! UTF-8-encoded string.
//!
//! This string atom corresponds to Rust's normal `str` and `String` types, since it is
//! UTF-8-encoded. A literal also contains, apart from the string, the URID of it's language.
//!
//! When initialized, a literal does not contain any text. Every text has to be appended to the
//! literal using the [`LiteralWritingFrame`](trait.LiteralWritingFrame.html) trait. Every
//! writing frame implements this trait via a blanket implementation and the trait is included in
//! the crate's prelude. You can, therefore, act as if the extended methods were normal methods of a
//! writing frame.
//!
//! You can aquire a literal's data using the [`lang` method](type.Literal.html#method.lang)
//! and the [`as_str` method](type.Literal.html#method.as_str).
//!
//! An example:
//!
//!     extern crate lv2rs_atom as atom;
//!     extern crate lv2rs_urid as urid;
//!
//!     use atom::prelude::*;
//!     use atom::ports::*;
//!     use urid::{CachedMap, debug::DebugMap};
//!     use std::ffi::CStr;
//!
//!     pub struct Plugin {
//!         in_port: AtomInputPort<Literal>,
//!         out_port: AtomOutputPort<Literal>,
//!         urids: CachedMap,
//!     }
//!
//!     impl Plugin {
//!         /// Simulated `run` method.
//!         fn run(&mut self) {
//!             // Writing
//!             {
//!                 let mut frame =
//!                     unsafe { self.out_port.write_atom_body(&0, &mut self.urids) }.unwrap();
//!                 frame.append_string("Hello World!");
//!             }
//!
//!             // Reading.
//!             let literal = unsafe { self.in_port.get_atom_body(&mut self.urids) }.unwrap();
//!             let message = literal.as_str().unwrap();
//!             assert_eq!("Hello World!", message);
//!         }
//!     }
//!
//!     // Getting a debug URID map.
//!     let mut debug_map = DebugMap::new();
//!     let mut urids = unsafe {debug_map.create_cached_map()};
//!
//!     // Creating the plugin.
//!     let mut plugin = Plugin {
//!         in_port: AtomInputPort::new(),
//!         out_port: AtomOutputPort::new(),
//!         urids: urids,
//!     };
//!
//!     // Creating the atom space.
//!     let mut atom_space = vec![0u8; 256];
//!     let atom = unsafe { (atom_space.as_mut_ptr() as *mut Atom).as_mut() }.unwrap();
//!     *(atom.mut_size()) = 256 - 8;
//!
//!     // Connecting the ports.
//!     plugin.in_port.connect_port(atom as &Atom);
//!     plugin.out_port.connect_port(atom);
//!
//!     // Calling `run`.
//!     plugin.run();
use crate::atom::{array::*, *};
use crate::frame::{WritingFrame, WritingFrameExt};
use crate::uris;
use std::ffi::CStr;
use urid::URID;

/// The body header of a literal.
///
/// It contains the URID of the datatype (some obscure RDF feature) and of the language. It is also
/// `repr(C)` and is used to interpret raw atoms.
#[repr(C)]
pub struct LiteralHeader {
    pub datatype: URID,
    pub lang: URID,
}

/// UTF-8 encoded string.
///
/// See the [module documentation](index.html) for more information.
pub type Literal = ArrayAtomBody<LiteralHeader, u8>;

impl ArrayAtomHeader for LiteralHeader {
    type InitializationParameter = URID;

    unsafe fn initialize<'a, W, T>(
        writer: &mut W,
        language: &URID,
        _urids: &mut urid::CachedMap,
    ) -> Result<(), ()>
    where
        T: 'static + Sized + Copy,
        ArrayAtomBody<Self, T>: AtomBody,
        W: WritingFrame<'a> + WritingFrameExt<'a, ArrayAtomBody<Self, T>>,
    {
        let header = LiteralHeader {
            datatype: 0,
            lang: *language,
        };
        writer.write_sized(&header)?;
        Ok(())
    }
}

impl AtomBody for Literal {
    type InitializationParameter = URID;

    fn get_uri() -> &'static CStr {
        unsafe { CStr::from_bytes_with_nul_unchecked(uris::LITERAL_TYPE_URI) }
    }

    unsafe fn initialize_body<'a, W>(
        writer: &mut W,
        language: &URID,
        urids: &mut urid::CachedMap,
    ) -> Result<(), ()>
    where
        W: WritingFrame<'a> + WritingFrameExt<'a, Self>,
    {
        Self::__initialize_body(writer, language, urids)
    }

    fn create_ref<'a>(raw_data: &'a [u8]) -> Result<&'a Self, ()> {
        Self::__create_ref(raw_data)
    }
}

impl Literal {
    /// Try to parse the literal data as a `&str`
    ///
    /// Parsing errors are forwarded.
    pub fn as_str(&self) -> Result<&str, std::str::Utf8Error> {
        let bytes = &self.data;
        std::str::from_utf8(bytes)
    }

    /// Return the language of the literal.
    pub fn lang(&self) -> URID {
        self.header.lang
    }
}

/// Extension for [`WritingFrame`](../frame/trait.WritingFrame.html) and
/// [`WritingFrameExt`](../frame/trait.WritingFrameExt.html) for vectors.
///
/// See the [module documentation](index.html) for more information.
pub trait LiteralWritingFrame<'a>: WritingFrame<'a> + WritingFrameExt<'a, Literal> {
    /// Append a string to the literal.
    ///
    /// In case of insufficient memory, `Err` is returned.
    fn append_string(&mut self, string: &str) -> Result<(), ()> {
        unsafe { Literal::append(self, string.as_bytes()) }
    }
}

impl<'a, W> LiteralWritingFrame<'a> for W where W: WritingFrame<'a> + WritingFrameExt<'a, Literal> {}