79 lines
2.0 KiB
Rust
79 lines
2.0 KiB
Rust
//! Low level Postgres protocol APIs.
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//!
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//! This crate implements the low level components of Postgres's communication
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//! protocol, including message and value serialization and deserialization.
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//! It is designed to be used as a building block by higher level APIs such as
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//! `rust-postgres`, and should not typically be used directly.
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//!
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//! # Note
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//!
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//! This library assumes that the `client_encoding` backend parameter has been
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//! set to `UTF8`. It will most likely not behave properly if that is not the case.
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#![doc(html_root_url = "https://docs.rs/postgres-protocol/0.6")]
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#![warn(missing_docs, rust_2018_idioms, clippy::all)]
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use byteorder::{BigEndian, ByteOrder};
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use bytes::{BufMut, BytesMut};
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use std::io;
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pub mod authentication;
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pub mod escape;
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pub mod message;
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pub mod password;
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pub mod types;
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/// A Postgres OID.
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pub type Oid = u32;
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/// A Postgres Log Sequence Number (LSN).
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pub type Lsn = u64;
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/// An enum indicating if a value is `NULL` or not.
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pub enum IsNull {
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/// The value is `NULL`.
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Yes,
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/// The value is not `NULL`.
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No,
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}
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fn write_nullable<F, E>(serializer: F, buf: &mut BytesMut) -> Result<(), E>
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where
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F: FnOnce(&mut BytesMut) -> Result<IsNull, E>,
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E: From<io::Error>,
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{
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let base = buf.len();
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buf.put_i32(0);
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let size = match serializer(buf)? {
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IsNull::No => i32::from_usize(buf.len() - base - 4)?,
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IsNull::Yes => -1,
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};
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BigEndian::write_i32(&mut buf[base..], size);
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Ok(())
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}
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trait FromUsize: Sized {
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fn from_usize(x: usize) -> Result<Self, io::Error>;
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}
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macro_rules! from_usize {
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($t:ty) => {
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impl FromUsize for $t {
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#[inline]
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fn from_usize(x: usize) -> io::Result<$t> {
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if x > <$t>::max_value() as usize {
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Err(io::Error::new(
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io::ErrorKind::InvalidInput,
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"value too large to transmit",
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))
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} else {
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Ok(x as $t)
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}
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}
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}
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};
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}
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from_usize!(i16);
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from_usize!(i32);
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