use std::io::{Writer, IoError};
use std::error::Error;
use std::num::Int;
use rustc_serialize::Encoder;
use super::SizeLimit;
pub type EncodingResult<T> = Result<T, EncodingError>;
#[derive(Show)]
pub enum EncodingError {
IoError(IoError),
SizeLimit
}
pub struct EncoderWriter<'a, W: 'a> {
writer: &'a mut W,
_size_limit: SizeLimit
}
pub struct SizeChecker {
size_limit: u64,
written: u64
}
fn wrap_io(err: IoError) -> EncodingError {
EncodingError::IoError(err)
}
impl Error for EncodingError {
fn description(&self) -> &str {
match *self {
EncodingError::IoError(ref err) => err.description(),
EncodingError::SizeLimit => "the size limit for decoding has been reached"
}
}
fn detail(&self) -> Option<String> {
match *self {
EncodingError::IoError(ref err) => err.detail(),
EncodingError::SizeLimit => None
}
}
}
impl <'a, W: Writer> EncoderWriter<'a, W> {
pub fn new(w: &'a mut W, size_limit: SizeLimit) -> EncoderWriter<'a, W> {
EncoderWriter {
writer: w,
_size_limit: size_limit
}
}
}
impl SizeChecker {
pub fn new(limit: u64) -> SizeChecker {
SizeChecker {
size_limit: limit,
written: 0
}
}
fn add_raw(&mut self, size: usize) -> EncodingResult<()> {
self.written += size as u64;
if self.written <= self.size_limit {
Ok(())
} else {
Err(EncodingError::SizeLimit)
}
}
fn add_value<T>(&mut self, t: T) -> EncodingResult<()> {
use std::mem::size_of_val;
self.add_raw(size_of_val(&t))
}
}
impl<'a, W: Writer> Encoder for EncoderWriter<'a, W> {
type Error = EncodingError;
fn emit_nil(&mut self) -> EncodingResult<()> { Ok(()) }
fn emit_usize(&mut self, v: usize) -> EncodingResult<()> {
self.emit_u64(v as u64)
}
fn emit_u64(&mut self, v: u64) -> EncodingResult<()> {
self.writer.write_be_u64(v).map_err(wrap_io)
}
fn emit_u32(&mut self, v: u32) -> EncodingResult<()> {
self.writer.write_be_u32(v).map_err(wrap_io)
}
fn emit_u16(&mut self, v: u16) -> EncodingResult<()> {
self.writer.write_be_u16(v).map_err(wrap_io)
}
fn emit_u8(&mut self, v: u8) -> EncodingResult<()> {
self.writer.write_u8(v).map_err(wrap_io)
}
fn emit_isize(&mut self, v: isize) -> EncodingResult<()> {
self.emit_i64(v as i64)
}
fn emit_i64(&mut self, v: i64) -> EncodingResult<()> {
self.writer.write_be_i64(v).map_err(wrap_io)
}
fn emit_i32(&mut self, v: i32) -> EncodingResult<()> {
self.writer.write_be_i32(v).map_err(wrap_io)
}
fn emit_i16(&mut self, v: i16) -> EncodingResult<()> {
self.writer.write_be_i16(v).map_err(wrap_io)
}
fn emit_i8(&mut self, v: i8) -> EncodingResult<()> {
self.writer.write_i8(v).map_err(wrap_io)
}
fn emit_bool(&mut self, v: bool) -> EncodingResult<()> {
self.writer.write_u8(if v {1} else {0}).map_err(wrap_io)
}
fn emit_f64(&mut self, v: f64) -> EncodingResult<()> {
self.writer.write_be_f64(v).map_err(wrap_io)
}
fn emit_f32(&mut self, v: f32) -> EncodingResult<()> {
self.writer.write_be_f32(v).map_err(wrap_io)
}
fn emit_char(&mut self, v: char) -> EncodingResult<()> {
self.writer.write_char(v).map_err(wrap_io)
}
fn emit_str(&mut self, v: &str) -> EncodingResult<()> {
try!(self.emit_usize(v.len()));
self.writer.write_str(v).map_err(wrap_io)
}
fn emit_enum<F>(&mut self, __: &str, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_enum_variant<F>(&mut self, _: &str,
v_id: usize,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
let max_u32: u32 = Int::max_value();
if v_id > (max_u32 as usize) {
panic!("Variant tag doesn't fit in a u32")
}
try!(self.emit_u32(v_id as u32));
f(self)
}
fn emit_enum_variant_arg<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_enum_struct_variant<F>(&mut self, _: &str,
_: usize,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_enum_struct_variant_field<F>(&mut self,
_: &str,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_struct<F>(&mut self, _: &str, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_struct_field<F>(&mut self, _: &str, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_tuple<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_tuple_arg<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_tuple_struct<F>(&mut self, _: &str, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
self.emit_tuple(len, f)
}
fn emit_tuple_struct_arg<F>(&mut self, f_idx: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
self.emit_tuple_arg(f_idx, f)
}
fn emit_option<F>(&mut self, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_option_none(&mut self) -> EncodingResult<()> {
self.writer.write_u8(0).map_err(wrap_io)
}
fn emit_option_some<F>(&mut self, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
try!(self.writer.write_u8(1).map_err(wrap_io));
f(self)
}
fn emit_seq<F>(&mut self, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
try!(self.emit_usize(len));
f(self)
}
fn emit_seq_elt<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_map<F>(&mut self, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
try!(self.emit_usize(len));
f(self)
}
fn emit_map_elt_key<F>(&mut self, _: usize, mut f: F) -> EncodingResult<()> where
F: FnMut(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
fn emit_map_elt_val<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut EncoderWriter<'a, W>) -> EncodingResult<()> {
f(self)
}
}
impl Encoder for SizeChecker {
type Error = EncodingError;
fn emit_nil(&mut self) -> EncodingResult<()> { Ok(()) }
fn emit_usize(&mut self, v: usize) -> EncodingResult<()> {
self.add_value(v as u64)
}
fn emit_u64(&mut self, v: u64) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_u32(&mut self, v: u32) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_u16(&mut self, v: u16) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_u8(&mut self, v: u8) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_isize(&mut self, v: isize) -> EncodingResult<()> {
self.add_value(v as i64)
}
fn emit_i64(&mut self, v: i64) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_i32(&mut self, v: i32) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_i16(&mut self, v: i16) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_i8(&mut self, v: i8) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_bool(&mut self, _: bool) -> EncodingResult<()> {
self.add_value(0 as u8)
}
fn emit_f64(&mut self, v: f64) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_f32(&mut self, v: f32) -> EncodingResult<()> {
self.add_value(v)
}
fn emit_char(&mut self, v: char) -> EncodingResult<()> {
self.add_raw(v.len_utf8())
}
fn emit_str(&mut self, v: &str) -> EncodingResult<()> {
self.add_raw(v.len())
}
fn emit_enum<F>(&mut self, __: &str, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_enum_variant<F>(&mut self, _: &str,
v_id: usize,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
try!(self.add_value(v_id as u32));
f(self)
}
fn emit_enum_variant_arg<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_enum_struct_variant<F>(&mut self, _: &str,
_: usize,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_enum_struct_variant_field<F>(&mut self,
_: &str,
_: usize,
f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_struct<F>(&mut self, _: &str, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_struct_field<F>(&mut self, _: &str, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_tuple<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_tuple_arg<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_tuple_struct<F>(&mut self, _: &str, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
self.emit_tuple(len, f)
}
fn emit_tuple_struct_arg<F>(&mut self, f_idx: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
self.emit_tuple_arg(f_idx, f)
}
fn emit_option<F>(&mut self, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_option_none(&mut self) -> EncodingResult<()> {
self.add_value(0 as u8)
}
fn emit_option_some<F>(&mut self, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
try!(self.add_value(1 as u8));
f(self)
}
fn emit_seq<F>(&mut self, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
try!(self.emit_usize(len));
f(self)
}
fn emit_seq_elt<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_map<F>(&mut self, len: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
try!(self.emit_usize(len));
f(self)
}
fn emit_map_elt_key<F>(&mut self, _: usize, mut f: F) -> EncodingResult<()> where
F: FnMut(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
fn emit_map_elt_val<F>(&mut self, _: usize, f: F) -> EncodingResult<()> where
F: FnOnce(&mut SizeChecker) -> EncodingResult<()> {
f(self)
}
}