diesel/pg/query_builder/copy/
mod.rs

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1use crate::pg::Pg;
2use crate::query_builder::nodes::StaticQueryFragment;
3use crate::query_builder::ColumnList;
4use crate::query_builder::QueryFragment;
5use crate::sql_types::SqlType;
6use crate::Expression;
7use crate::{Column, Table};
8
9pub(crate) mod copy_from;
10pub(crate) mod copy_to;
11
12#[cfg(feature = "postgres")]
13pub(crate) use self::copy_from::{CopyFromExpression, InternalCopyFromQuery};
14#[cfg(feature = "postgres")]
15pub(crate) use self::copy_to::CopyToCommand;
16
17pub use self::copy_from::{CopyFromQuery, CopyHeader, ExecuteCopyFromDsl};
18pub use self::copy_to::CopyToQuery;
19
20const COPY_MAGIC_HEADER: [u8; 11] = [
21    0x50, 0x47, 0x43, 0x4F, 0x50, 0x59, 0x0A, 0xFF, 0x0D, 0x0A, 0x00,
22];
23
24/// Describes the format used by `COPY FROM` or `COPY TO`
25/// statements
26///
27/// See [the postgresql documentation](https://www.postgresql.org/docs/current/sql-copy.html)
28/// for details about the different formats
29#[derive(Default, Debug, Copy, Clone)]
30pub enum CopyFormat {
31    /// The postgresql text format
32    ///
33    /// This format is the default if no format is explicitly set
34    #[default]
35    Text,
36    /// Represents the data as comma separated values (CSV)
37    Csv,
38    /// The postgresql binary format
39    Binary,
40}
41
42impl CopyFormat {
43    fn to_sql_format(self) -> &'static str {
44        match self {
45            CopyFormat::Text => "text",
46            CopyFormat::Csv => "csv",
47            CopyFormat::Binary => "binary",
48        }
49    }
50}
51
52#[derive(Default, Debug)]
53struct CommonOptions {
54    format: Option<CopyFormat>,
55    freeze: Option<bool>,
56    delimiter: Option<char>,
57    null: Option<String>,
58    quote: Option<char>,
59    escape: Option<char>,
60}
61
62impl CommonOptions {
63    fn any_set(&self) -> bool {
64        self.format.is_some()
65            || self.freeze.is_some()
66            || self.delimiter.is_some()
67            || self.null.is_some()
68            || self.quote.is_some()
69            || self.escape.is_some()
70    }
71
72    fn walk_ast<'b>(
73        &'b self,
74        mut pass: crate::query_builder::AstPass<'_, 'b, Pg>,
75        comma: &mut &'static str,
76    ) {
77        if let Some(format) = self.format {
78            pass.push_sql(comma);
79            *comma = ", ";
80            pass.push_sql("FORMAT ");
81            pass.push_sql(format.to_sql_format());
82        }
83        if let Some(freeze) = self.freeze {
84            pass.push_sql(&format!("{comma}FREEZE {}", freeze as u8));
85            *comma = ", ";
86        }
87        if let Some(delimiter) = self.delimiter {
88            pass.push_sql(&format!("{comma}DELIMITER '{delimiter}'"));
89            *comma = ", ";
90        }
91        if let Some(ref null) = self.null {
92            pass.push_sql(comma);
93            *comma = ", ";
94            pass.push_sql("NULL '");
95            // we cannot use binds here :(
96            pass.push_sql(null);
97            pass.push_sql("'");
98        }
99        if let Some(quote) = self.quote {
100            pass.push_sql(&format!("{comma}QUOTE '{quote}'"));
101            *comma = ", ";
102        }
103        if let Some(escape) = self.escape {
104            pass.push_sql(&format!("{comma}ESCAPE '{escape}'"));
105            *comma = ", ";
106        }
107    }
108}
109
110/// A expression that could be used as target/source for `COPY FROM` and `COPY TO` commands
111///
112/// This trait is implemented for any table type and for tuples of columns from the same table
113pub trait CopyTarget {
114    /// The table targeted by the command
115    type Table: Table;
116    /// The sql side type of the target expression
117    type SqlType: SqlType;
118
119    #[doc(hidden)]
120    fn walk_target(pass: crate::query_builder::AstPass<'_, '_, Pg>) -> crate::QueryResult<()>;
121}
122
123impl<T> CopyTarget for T
124where
125    T: Table + StaticQueryFragment,
126    T::SqlType: SqlType,
127    T::AllColumns: ColumnList,
128    T::Component: QueryFragment<Pg>,
129{
130    type Table = Self;
131    type SqlType = T::SqlType;
132
133    fn walk_target(mut pass: crate::query_builder::AstPass<'_, '_, Pg>) -> crate::QueryResult<()> {
134        T::STATIC_COMPONENT.walk_ast(pass.reborrow())?;
135        pass.push_sql("(");
136        T::all_columns().walk_ast(pass.reborrow())?;
137        pass.push_sql(")");
138        Ok(())
139    }
140}
141
142macro_rules! copy_target_for_columns {
143    ($(
144        $Tuple:tt {
145            $(($idx:tt) -> $T:ident, $ST:ident, $TT:ident,)+
146        }
147    )+) => {
148        $(
149            impl<T, $($ST,)*> CopyTarget for ($($ST,)*)
150            where
151                $($ST: Column<Table = T> + Default,)*
152                ($(<$ST as Expression>::SqlType,)*): SqlType,
153                T: Table + StaticQueryFragment,
154                T::Component: QueryFragment<Pg>,
155                Self: ColumnList,
156            {
157                type Table = T;
158                type SqlType = crate::dsl::SqlTypeOf<Self>;
159
160                fn walk_target(
161                    mut pass: crate::query_builder::AstPass<'_, '_, Pg>,
162                ) -> crate::QueryResult<()> {
163                    T::STATIC_COMPONENT.walk_ast(pass.reborrow())?;
164                    pass.push_sql("(");
165                    <Self as ColumnList>::walk_ast(&($($ST::default(),)*), pass.reborrow())?;
166                    pass.push_sql(")");
167                    Ok(())
168                }
169            }
170        )*
171    }
172}
173
174diesel_derives::__diesel_for_each_tuple!(copy_target_for_columns);
diesel/pg/query_builder/copy/mod.rs

diesel/pg/query_builder/copy/
mod.rs
