diesel/mysql/
value.rs

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1use super::types::date_and_time::MysqlTime;
2use super::MysqlType;
3use crate::deserialize;
4use std::error::Error;
5
6/// Raw mysql value as received from the database
7#[derive(Clone, Debug)]
8pub struct MysqlValue<'a> {
9    raw: &'a [u8],
10    tpe: MysqlType,
11}
12
13impl<'a> MysqlValue<'a> {
14    /// Create a new instance of [MysqlValue] based on a byte buffer
15    /// and information about the type of the value represented by the
16    /// given buffer
17    #[cfg(feature = "i-implement-a-third-party-backend-and-opt-into-breaking-changes")]
18    pub fn new(raw: &'a [u8], tpe: MysqlType) -> Self {
19        Self::new_internal(raw, tpe)
20    }
21
22    pub(in crate::mysql) fn new_internal(raw: &'a [u8], tpe: MysqlType) -> Self {
23        Self { raw, tpe }
24    }
25
26    /// Get the underlying raw byte representation
27    pub fn as_bytes(&self) -> &[u8] {
28        self.raw
29    }
30
31    /// Get the mysql type of the current value
32    pub fn value_type(&self) -> MysqlType {
33        self.tpe
34    }
35
36    /// Checks that the type code is valid, and interprets the data as a
37    /// `MysqlTime` pointer
38    // We use `ptr.read_unaligned()` to read the potential unaligned ptr,
39    // so clippy is clearly wrong here
40    // https://github.com/rust-lang/rust-clippy/issues/2881
41    #[allow(dead_code, clippy::cast_ptr_alignment)]
42    #[allow(unsafe_code)] // pointer cast
43    pub(crate) fn time_value(&self) -> deserialize::Result<MysqlTime> {
44        match self.tpe {
45            MysqlType::Time | MysqlType::Date | MysqlType::DateTime | MysqlType::Timestamp => {
46                let ptr = self.raw.as_ptr() as *const MysqlTime;
47                let result = unsafe { ptr.read_unaligned() };
48                if result.neg {
49                    Err("Negative dates/times are not yet supported".into())
50                } else {
51                    Ok(result)
52                }
53            }
54            _ => Err(self.invalid_type_code("timestamp")),
55        }
56    }
57
58    /// Returns the numeric representation of this value, based on the type code.
59    /// Returns an error if the type code is not numeric.
60    pub(crate) fn numeric_value(&self) -> deserialize::Result<NumericRepresentation<'_>> {
61        Ok(match self.tpe {
62            MysqlType::UnsignedTiny | MysqlType::Tiny => {
63                NumericRepresentation::Tiny(self.raw[0].try_into()?)
64            }
65            MysqlType::UnsignedShort | MysqlType::Short => {
66                NumericRepresentation::Small(i16::from_ne_bytes((&self.raw[..2]).try_into()?))
67            }
68            MysqlType::UnsignedLong | MysqlType::Long => {
69                NumericRepresentation::Medium(i32::from_ne_bytes((&self.raw[..4]).try_into()?))
70            }
71            MysqlType::UnsignedLongLong | MysqlType::LongLong => {
72                NumericRepresentation::Big(i64::from_ne_bytes(self.raw.try_into()?))
73            }
74            MysqlType::Float => {
75                NumericRepresentation::Float(f32::from_ne_bytes(self.raw.try_into()?))
76            }
77            MysqlType::Double => {
78                NumericRepresentation::Double(f64::from_ne_bytes(self.raw.try_into()?))
79            }
80
81            MysqlType::Numeric => NumericRepresentation::Decimal(self.raw),
82            _ => return Err(self.invalid_type_code("number")),
83        })
84    }
85
86    fn invalid_type_code(&self, expected: &str) -> Box<dyn Error + Send + Sync> {
87        format!(
88            "Invalid representation received for {}: {:?}",
89            expected, self.tpe
90        )
91        .into()
92    }
93}
94
95/// Represents all possible forms MySQL transmits integers
96#[derive(Debug, Clone, Copy)]
97#[non_exhaustive]
98pub enum NumericRepresentation<'a> {
99    /// Corresponds to `MYSQL_TYPE_TINY`
100    Tiny(i8),
101    /// Corresponds to `MYSQL_TYPE_SHORT`
102    Small(i16),
103    /// Corresponds to `MYSQL_TYPE_INT24` and `MYSQL_TYPE_LONG`
104    Medium(i32),
105    /// Corresponds to `MYSQL_TYPE_LONGLONG`
106    Big(i64),
107    /// Corresponds to `MYSQL_TYPE_FLOAT`
108    Float(f32),
109    /// Corresponds to `MYSQL_TYPE_DOUBLE`
110    Double(f64),
111    /// Corresponds to `MYSQL_TYPE_DECIMAL` and `MYSQL_TYPE_NEWDECIMAL`
112    Decimal(&'a [u8]),
113}
diesel/mysql/value.rs

diesel/mysql/
value.rs
