diesel/pg/types/
array.rs

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
use byteorder::{NetworkEndian, ReadBytesExt, WriteBytesExt};
use std::fmt;
use std::io::Write;

use crate::deserialize::{self, FromSql};
use crate::pg::{Pg, PgTypeMetadata, PgValue};
use crate::query_builder::bind_collector::ByteWrapper;
use crate::serialize::{self, IsNull, Output, ToSql};
use crate::sql_types::{Array, HasSqlType, Nullable};

#[cfg(feature = "postgres_backend")]
impl<T> HasSqlType<Array<T>> for Pg
where
    Pg: HasSqlType<T>,
{
    fn metadata(lookup: &mut Self::MetadataLookup) -> PgTypeMetadata {
        match <Pg as HasSqlType<T>>::metadata(lookup).0 {
            Ok(tpe) => PgTypeMetadata::new(tpe.array_oid, 0),
            c @ Err(_) => PgTypeMetadata(c),
        }
    }
}

#[cfg(feature = "postgres_backend")]
impl<T, ST> FromSql<Array<ST>, Pg> for Vec<T>
where
    T: FromSql<ST, Pg>,
{
    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
        let mut bytes = value.as_bytes();
        let num_dimensions = bytes.read_i32::<NetworkEndian>()?;
        let has_null = bytes.read_i32::<NetworkEndian>()? != 0;
        let _oid = bytes.read_i32::<NetworkEndian>()?;

        if num_dimensions == 0 {
            return Ok(Vec::new());
        }

        let num_elements = bytes.read_i32::<NetworkEndian>()?;
        let _lower_bound = bytes.read_i32::<NetworkEndian>()?;

        if num_dimensions != 1 {
            return Err("multi-dimensional arrays are not supported".into());
        }

        (0..num_elements)
            .map(|_| {
                let elem_size = bytes.read_i32::<NetworkEndian>()?;
                if has_null && elem_size == -1 {
                    T::from_nullable_sql(None)
                } else {
                    let (elem_bytes, new_bytes) = bytes.split_at(elem_size.try_into()?);
                    bytes = new_bytes;
                    T::from_sql(PgValue::new_internal(elem_bytes, &value))
                }
            })
            .collect()
    }
}

use crate::expression::bound::Bound;
use crate::expression::AsExpression;

macro_rules! array_as_expression {
    ($ty:ty, $sql_type:ty) => {
        #[cfg(feature = "postgres_backend")]
        // this simplifies the macro implementation
        // as some macro calls use this lifetime
        #[allow(clippy::extra_unused_lifetimes)]
        impl<'a, 'b, ST: 'static, T> AsExpression<$sql_type> for $ty {
            type Expression = Bound<$sql_type, Self>;

            fn as_expression(self) -> Self::Expression {
                Bound::new(self)
            }
        }
    };
}

array_as_expression!(&'a [T], Array<ST>);
array_as_expression!(&'a [T], Nullable<Array<ST>>);
array_as_expression!(&'a &'b [T], Array<ST>);
array_as_expression!(&'a &'b [T], Nullable<Array<ST>>);
array_as_expression!(Vec<T>, Array<ST>);
array_as_expression!(Vec<T>, Nullable<Array<ST>>);
array_as_expression!(&'a Vec<T>, Array<ST>);
array_as_expression!(&'a Vec<T>, Nullable<Array<ST>>);
array_as_expression!(&'a &'b Vec<T>, Array<ST>);
array_as_expression!(&'a &'b Vec<T>, Nullable<Array<ST>>);

#[cfg(feature = "postgres_backend")]
impl<ST, T> ToSql<Array<ST>, Pg> for [T]
where
    Pg: HasSqlType<ST>,
    T: ToSql<ST, Pg>,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
        let num_dimensions = 1;
        out.write_i32::<NetworkEndian>(num_dimensions)?;
        let flags = 0;
        out.write_i32::<NetworkEndian>(flags)?;
        let element_oid = Pg::metadata(out.metadata_lookup()).oid()?;
        out.write_u32::<NetworkEndian>(element_oid)?;
        out.write_i32::<NetworkEndian>(self.len().try_into()?)?;
        let lower_bound = 1;
        out.write_i32::<NetworkEndian>(lower_bound)?;

        // This buffer is created outside of the loop to reuse the underlying memory allocation
        // For most cases all array elements will have the same serialized size
        let mut buffer = Vec::new();

        for elem in self.iter() {
            let is_null = {
                let mut temp_buffer = Output::new(ByteWrapper(&mut buffer), out.metadata_lookup());
                elem.to_sql(&mut temp_buffer)?
            };

            if let IsNull::No = is_null {
                out.write_i32::<NetworkEndian>(buffer.len().try_into()?)?;
                out.write_all(&buffer)?;
                buffer.clear();
            } else {
                // https://github.com/postgres/postgres/blob/82f8107b92c9104ec9d9465f3f6a4c6dab4c124a/src/backend/utils/adt/arrayfuncs.c#L1461
                out.write_i32::<NetworkEndian>(-1)?;
            }
        }

        Ok(IsNull::No)
    }
}

#[cfg(feature = "postgres_backend")]
impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for [T]
where
    [T]: ToSql<Array<ST>, Pg>,
    ST: 'static,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
        ToSql::<Array<ST>, Pg>::to_sql(self, out)
    }
}

#[cfg(feature = "postgres_backend")]
impl<ST, T> ToSql<Array<ST>, Pg> for Vec<T>
where
    ST: 'static,
    [T]: ToSql<Array<ST>, Pg>,
    T: fmt::Debug,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
        (self as &[T]).to_sql(out)
    }
}

#[cfg(feature = "postgres_backend")]
impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for Vec<T>
where
    ST: 'static,
    Vec<T>: ToSql<Array<ST>, Pg>,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
        ToSql::<Array<ST>, Pg>::to_sql(self, out)
    }
}