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use bytes::Buf;
use std::borrow::Cow;
use cdbc::decode::Decode;
use cdbc::encode::{Encode, IsNull};
use cdbc::error::BoxDynError;
use crate::type_info::PgType;
use crate::{PgArgumentBuffer, PgTypeInfo, PgValueFormat, PgValueRef, Postgres};
use cdbc::types::Type;
pub trait PgHasArrayType {
fn array_type_info() -> PgTypeInfo;
fn array_compatible(ty: &PgTypeInfo) -> bool {
*ty == Self::array_type_info()
}
}
impl<T> PgHasArrayType for Option<T>
where
T: PgHasArrayType,
{
fn array_type_info() -> PgTypeInfo {
T::array_type_info()
}
fn array_compatible(ty: &PgTypeInfo) -> bool {
T::array_compatible(ty)
}
}
impl<T> Type<Postgres> for [T]
where
T: PgHasArrayType,
{
fn type_info() -> PgTypeInfo {
T::array_type_info()
}
fn compatible(ty: &PgTypeInfo) -> bool {
T::array_compatible(ty)
}
}
impl<T> Type<Postgres> for Vec<T>
where
T: PgHasArrayType,
{
fn type_info() -> PgTypeInfo {
T::array_type_info()
}
fn compatible(ty: &PgTypeInfo) -> bool {
T::array_compatible(ty)
}
}
impl<'q, T> Encode<'q, Postgres> for Vec<T>
where
for<'a> &'a [T]: Encode<'q, Postgres>,
T: Encode<'q, Postgres>,
{
#[inline]
fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> IsNull {
self.as_slice().encode_by_ref(buf)
}
}
impl<'q, T> Encode<'q, Postgres> for &'_ [T]
where
T: Encode<'q, Postgres> + Type<Postgres>,
{
fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> IsNull {
let type_info = if self.len() < 1 {
T::type_info()
} else {
self[0].produces().unwrap_or_else(T::type_info)
};
buf.extend(&1_i32.to_be_bytes()); // number of dimensions
buf.extend(&0_i32.to_be_bytes()); // flags
// element type
match type_info.0 {
PgType::DeclareWithName(name) => buf.patch_type_by_name(&name),
ty => {
buf.extend(&ty.oid().to_be_bytes());
}
}
buf.extend(&(self.len() as i32).to_be_bytes()); // len
buf.extend(&1_i32.to_be_bytes()); // lower bound
for element in self.iter() {
buf.encode(element);
}
IsNull::No
}
}
impl<'r, T> Decode<'r, Postgres> for Vec<T>
where
T: for<'a> Decode<'a, Postgres> + Type<Postgres>,
{
fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError> {
let format = value.format();
match format {
PgValueFormat::Binary => {
// https://github.com/postgres/postgres/blob/a995b371ae29de2d38c4b7881cf414b1560e9746/src/backend/utils/adt/arrayfuncs.c#L1548
let mut buf = value.as_bytes()?;
// number of dimensions in the array
let ndim = buf.get_i32();
if ndim == 0 {
// zero dimensions is an empty array
return Ok(Vec::new());
}
if ndim != 1 {
return Err(format!("encountered an array of {} dimensions; only one-dimensional arrays are supported", ndim).into());
}
// appears to have been used in the past to communicate potential NULLS
// but reading source code back through our supported postgres versions (9.5+)
// this is never used for anything
let _flags = buf.get_i32();
// the OID of the element
let element_type_oid = buf.get_u32();
let element_type_info: PgTypeInfo = PgTypeInfo::try_from_oid(element_type_oid)
.or_else(|| value.type_info.try_array_element().map(Cow::into_owned))
.unwrap_or_else(|| PgTypeInfo(PgType::DeclareWithOid(element_type_oid)));
// length of the array axis
let len = buf.get_i32();
// the lower bound, we only support arrays starting from "1"
let lower = buf.get_i32();
if lower != 1 {
return Err(format!("encountered an array with a lower bound of {} in the first dimension; only arrays starting at one are supported", lower).into());
}
let mut elements = Vec::with_capacity(len as usize);
for _ in 0..len {
elements.push(T::decode(PgValueRef::get(
&mut buf,
format,
element_type_info.clone(),
))?)
}
Ok(elements)
}
PgValueFormat::Text => {
// no type is provided from the database for the element
let element_type_info = T::type_info();
let s = value.as_str()?;
// https://github.com/postgres/postgres/blob/a995b371ae29de2d38c4b7881cf414b1560e9746/src/backend/utils/adt/arrayfuncs.c#L718
// trim the wrapping braces
let s = &s[1..(s.len() - 1)];
if s.is_empty() {
// short-circuit empty arrays up here
return Ok(Vec::new());
}
// NOTE: Nearly *all* types use ',' as the sequence delimiter. Yes, there is one
// that does not. The BOX (not PostGIS) type uses ';' as a delimiter.
// TODO: When we add support for BOX we need to figure out some way to make the
// delimiter selection
let delimiter = ',';
let mut done = false;
let mut in_quotes = false;
let mut in_escape = false;
let mut value = String::with_capacity(10);
let mut chars = s.chars();
let mut elements = Vec::with_capacity(4);
while !done {
loop {
match chars.next() {
Some(ch) => match ch {
_ if in_escape => {
value.push(ch);
in_escape = false;
}
'"' => {
in_quotes = !in_quotes;
}
'\\' => {
in_escape = true;
}
_ if ch == delimiter && !in_quotes => {
break;
}
_ => {
value.push(ch);
}
},
None => {
done = true;
break;
}
}
}
let value_opt = if value == "NULL" {
None
} else {
Some(value.as_bytes())
};
elements.push(T::decode(PgValueRef {
value: value_opt,
row: None,
type_info: element_type_info.clone(),
format,
})?);
value.clear();
}
Ok(elements)
}
}
}
}