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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320
use std;
use std::io::{self, Cursor, ErrorKind, Read};
use std::str;
use rmp::decode::{read_marker, RmpRead};
use rmp::Marker;
use super::Error;
use crate::{Utf8StringRef, ValueRef};
fn read_str_data<'a, R>(rd: &mut R, len: usize, depth: u16) -> Result<Utf8StringRef<'a>, Error>
where R: BorrowRead<'a>
{
let depth = super::decrement_depth(depth)?;
let buf = read_bin_data(rd, len, depth)?;
match str::from_utf8(buf) {
Ok(s) => Ok(Utf8StringRef::from(s)),
Err(err) => {
let s = Utf8StringRef {
s: Err((buf, err)),
};
Ok(s)
}
}
}
fn read_bin_data<'a, R>(rd: &mut R, len: usize, depth: u16) -> Result<&'a [u8], Error>
where R: BorrowRead<'a>
{
let _depth = super::decrement_depth(depth)?;
let buf = rd.fill_buf();
if len > buf.len() {
return Err(Error::InvalidDataRead(io::Error::new(ErrorKind::UnexpectedEof, "unexpected EOF")));
}
// Take a slice.
let buf = &buf[..len];
rd.consume(len);
Ok(buf)
}
fn read_ext_body<'a, R>(rd: &mut R, len: usize, depth: u16) -> Result<(i8, &'a [u8]), Error>
where R: BorrowRead<'a>
{
let depth = super::decrement_depth(depth)?;
let ty = rd.read_data_i8()?;
let buf = read_bin_data(rd, len, depth)?;
Ok((ty, buf))
}
fn read_array_data<'a, R>(rd: &mut R, mut len: usize, depth: u16) -> Result<Vec<ValueRef<'a>>, Error>
where R: BorrowRead<'a>
{
let depth = super::decrement_depth(depth)?;
// Note: Do not preallocate a Vec of size `len`.
// See https://github.com/3Hren/msgpack-rust/issues/151
let mut vec = Vec::new();
while len > 0 {
vec.push(read_value_ref_inner(rd, depth)?);
len -= 1;
}
Ok(vec)
}
fn read_map_data<'a, R>(rd: &mut R, mut len: usize, depth: u16) -> Result<Vec<(ValueRef<'a>, ValueRef<'a>)>, Error>
where R: BorrowRead<'a>
{
let depth = super::decrement_depth(depth)?;
// Note: Do not preallocate a Vec of size `len`.
// See https://github.com/3Hren/msgpack-rust/issues/151
let mut vec = Vec::new();
while len > 0 {
vec.push((read_value_ref_inner(rd, depth)?, read_value_ref_inner(rd, depth)?));
len -= 1;
}
Ok(vec)
}
/// A `BorrowRead` is a type of Reader which has an internal buffer.
///
/// This magic trait acts like a standard `BufRead` but unlike the standard this has an explicit
/// internal buffer lifetime, which allows to borrow from underlying buffer while consuming bytes.
pub trait BorrowRead<'a>: Read {
/// Returns the buffer contents.
///
/// This function is a lower-level call. It needs to be paired with the consume method to
/// function properly. When calling this method, none of the contents will be "read" in the
/// sense that later calling read may return the same contents. As such, consume must be called
/// with the number of bytes that are consumed from this buffer to ensure that the bytes are
/// never returned twice.
///
/// An empty buffer returned indicates that the stream has reached EOF.
fn fill_buf(&self) -> &'a [u8];
/// Tells this buffer that len bytes have been consumed from the buffer, so they should no
/// longer be returned in calls to read.
fn consume(&mut self, len: usize);
}
impl<'a> BorrowRead<'a> for &'a [u8] {
fn fill_buf(&self) -> &'a [u8] {
self
}
fn consume(&mut self, len: usize) {
*self = &(*self)[len..];
}
}
/// Useful when you want to know how much bytes has been consumed during `ValueRef` decoding.
impl<'a> BorrowRead<'a> for Cursor<&'a [u8]> {
fn fill_buf(&self) -> &'a [u8] {
let len = std::cmp::min(self.position(), self.get_ref().len() as u64);
&self.get_ref()[len as usize..]
}
fn consume(&mut self, len: usize) {
let pos = self.position();
self.set_position(pos + len as u64);
}
}
fn read_value_ref_inner<'a, R>(rd: &mut R, depth: u16) -> Result<ValueRef<'a>, Error>
where R: BorrowRead<'a>
{
let depth = super::decrement_depth(depth)?;
// Reading the marker involves either 1 byte read or nothing. On success consumes strictly
// 1 byte from the `rd`.
let val = match read_marker(rd)? {
Marker::Null => ValueRef::Nil,
Marker::True => ValueRef::Boolean(true),
Marker::False => ValueRef::Boolean(false),
Marker::FixPos(val) => ValueRef::from(val),
Marker::FixNeg(val) => ValueRef::from(val),
Marker::U8 => ValueRef::from(rd.read_data_u8()?),
Marker::U16 => ValueRef::from(rd.read_data_u16()?),
Marker::U32 => ValueRef::from(rd.read_data_u32()?),
Marker::U64 => ValueRef::from(rd.read_data_u64()?),
Marker::I8 => ValueRef::from(rd.read_data_i8()?),
Marker::I16 => ValueRef::from(rd.read_data_i16()?),
Marker::I32 => ValueRef::from(rd.read_data_i32()?),
Marker::I64 => ValueRef::from(rd.read_data_i64()?),
Marker::F32 => ValueRef::F32(rd.read_data_f32()?),
Marker::F64 => ValueRef::F64(rd.read_data_f64()?),
Marker::FixStr(len) => {
let res = read_str_data(rd, len as usize, depth)?;
ValueRef::String(res)
}
Marker::Str8 => {
let len = rd.read_data_u8()?;
let res = read_str_data(rd, len as usize, depth)?;
ValueRef::String(res)
}
Marker::Str16 => {
let len = rd.read_data_u16()?;
let res = read_str_data(rd, len as usize, depth)?;
ValueRef::String(res)
}
Marker::Str32 => {
let len = rd.read_data_u32()?;
let res = read_str_data(rd, len as usize, depth)?;
ValueRef::String(res)
}
Marker::Bin8 => {
let len = rd.read_data_u8()?;
let res = read_bin_data(rd, len as usize, depth)?;
ValueRef::Binary(res)
}
Marker::Bin16 => {
let len = rd.read_data_u16()?;
let res = read_bin_data(rd, len as usize, depth)?;
ValueRef::Binary(res)
}
Marker::Bin32 => {
let len = rd.read_data_u32()?;
let res = read_bin_data(rd, len as usize, depth)?;
ValueRef::Binary(res)
}
Marker::FixArray(len) => {
let vec = read_array_data(rd, len as usize, depth)?;
ValueRef::Array(vec)
}
Marker::Array16 => {
let len = rd.read_data_u16()?;
let vec = read_array_data(rd, len as usize, depth)?;
ValueRef::Array(vec)
}
Marker::Array32 => {
let len = rd.read_data_u32()?;
let vec = read_array_data(rd, len as usize, depth)?;
ValueRef::Array(vec)
}
Marker::FixMap(len) => {
let map = read_map_data(rd, len as usize, depth)?;
ValueRef::Map(map)
}
Marker::Map16 => {
let len = rd.read_data_u16()?;
let map = read_map_data(rd, len as usize, depth)?;
ValueRef::Map(map)
}
Marker::Map32 => {
let len = rd.read_data_u32()?;
let map = read_map_data(rd, len as usize, depth)?;
ValueRef::Map(map)
}
Marker::FixExt1 => {
let len = 1;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::FixExt2 => {
let len = 2;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::FixExt4 => {
let len = 4;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::FixExt8 => {
let len = 8;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::FixExt16 => {
let len = 16;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::Ext8 => {
let len = rd.read_data_u8()?;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::Ext16 => {
let len = rd.read_data_u16()?;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::Ext32 => {
let len = rd.read_data_u32()?;
let (ty, vec) = read_ext_body(rd, len as usize, depth)?;
ValueRef::Ext(ty, vec)
}
Marker::Reserved => ValueRef::Nil,
};
Ok(val)
}
/// Attempts to read the data from the given reader until either a complete MessagePack value
/// decoded or an error detected.
///
/// Returns either a non-owning `ValueRef`, which borrows the buffer from the given reader or an
/// error.
///
/// The reader should meet the requirement of a special `BorrowRead` trait, which allows to mutate
/// itself but permits to mutate the buffer it contains. It allows to perform a completely
/// zero-copy reading without a data loss fear in case of an error.
///
/// Currently only two types fit in this requirement: `&[u8]` and `Cursor<&[u8]>`. Using Cursor is
/// helpful, when you need to know how exactly many bytes the decoded `ValueRef` consumes. A `Vec<u8>`
/// type doesn't fit in the `BorrowRead` requirement, because its mut reference can mutate the
/// underlying buffer - use `Vec::as_slice()` if you need to decode a value from the vector.
///
/// # Errors
///
/// Returns an `Error` value if unable to continue the decoding operation either because of read
/// failure or any other circumstances. See `Error` documentation for more information.
///
/// This function enforces a maximum recursion depth of [`MAX_DEPTH`](super::MAX_DEPTH) and returns
/// [`Error::DepthLimitExceeded`] if the maximum is hit. If you run into stack overflows despite
/// this, use [`read_value_ref_with_max_depth`] with a custom maximum depth.
///
/// # Examples
/// ```
/// use rmpv::ValueRef;
/// use rmpv::decode::read_value_ref;
///
/// let buf = [0xaa, 0x6c, 0x65, 0x20, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65];
/// let mut rd = &buf[..];
///
/// assert_eq!(ValueRef::from("le message"), read_value_ref(&mut rd).unwrap());
/// ```
#[inline(never)]
pub fn read_value_ref<'a, R>(rd: &mut R) -> Result<ValueRef<'a>, Error>
where R: BorrowRead<'a>
{
read_value_ref_inner(rd, super::MAX_DEPTH as _)
}
/// Attempts to read the data from the given reader until either a complete MessagePack value
/// decoded or an error detected.
///
/// Returns either a non-owning `ValueRef`, which borrows the buffer from the given reader or an
/// error.
///
/// See [`read_value_ref`] for more information on how to use this function. This variant allows
/// you to specify the maximum recursion depth, if [`MAX_DEPTH`](super::MAX_DEPTH) is too high.
///
/// # Errors
///
/// Same as [`read_value_ref`], using the `max_depth` parameter in place of
/// [`MAX_DEPTH`](super::MAX_DEPTH).
#[inline(never)]
pub fn read_value_ref_with_max_depth<'a, R>(rd: &mut R, max_depth: usize) -> Result<ValueRef<'a>, Error>
where R: BorrowRead<'a>
{
read_value_ref_inner(rd, max_depth.min(u16::MAX as _) as u16)
}