value.rs - source

sqlparser/ast/

value.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18#[cfg(not(feature = "std"))]
19use alloc::string::String;
20
21use core::fmt;
22
23#[cfg(feature = "bigdecimal")]
24use bigdecimal::BigDecimal;
25
26#[cfg(feature = "serde")]
27use serde::{Deserialize, Serialize};
28
29use crate::{ast::Ident, tokenizer::Span};
30#[cfg(feature = "visitor")]
31use sqlparser_derive::{Visit, VisitMut};
32
33/// Wraps a primitive SQL [`Value`]  with its [`Span`] location
34///
35/// # Example: create a `ValueWithSpan` from a `Value`
36/// ```
37/// # use sqlparser::ast::{Value, ValueWithSpan};
38/// # use sqlparser::tokenizer::{Location, Span};
39/// let value = Value::SingleQuotedString(String::from("endpoint"));
40/// // from line 1, column 1 to line 1, column 7
41/// let span = Span::new(Location::new(1, 1), Location::new(1, 7));
42/// let value_with_span = value.with_span(span);
43/// ```
44///
45/// # Example: create a `ValueWithSpan` from a `Value` with an empty span
46///
47/// You can call [`Value::with_empty_span`] to create a `ValueWithSpan` with an empty span
48/// ```
49/// # use sqlparser::ast::{Value, ValueWithSpan};
50/// # use sqlparser::tokenizer::{Location, Span};
51/// let value = Value::SingleQuotedString(String::from("endpoint"));
52/// let value_with_span = value.with_empty_span();
53/// assert_eq!(value_with_span.span, Span::empty());
54/// ```
55///
56/// You can also use the [`From`] trait to convert  `ValueWithSpan` to/from `Value`s
57/// ```
58/// # use sqlparser::ast::{Value, ValueWithSpan};
59/// # use sqlparser::tokenizer::{Location, Span};
60/// let value = Value::SingleQuotedString(String::from("endpoint"));
61/// // converting `Value` to `ValueWithSpan` results in an empty span
62/// let value_with_span: ValueWithSpan = value.into();
63/// assert_eq!(value_with_span.span, Span::empty());
64/// // convert back to `Value`
65/// let value: Value = value_with_span.into();
66/// ```
67/// A `Value` paired with its source `Span` location.
68#[derive(Debug, Clone, Eq)]
69#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
70#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
71pub struct ValueWithSpan {
72    /// The wrapped `Value`.
73    pub value: Value,
74    /// The source `Span` covering the token(s) that produced the value.
75    pub span: Span,
76}
77
78impl PartialEq for ValueWithSpan {
79    fn eq(&self, other: &Self) -> bool {
80        self.value == other.value
81    }
82}
83
84impl Ord for ValueWithSpan {
85    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
86        self.value.cmp(&other.value)
87    }
88}
89
90impl PartialOrd for ValueWithSpan {
91    fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
92        Some(Ord::cmp(self, other))
93    }
94}
95
96impl core::hash::Hash for ValueWithSpan {
97    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
98        self.value.hash(state);
99    }
100}
101
102impl From<Value> for ValueWithSpan {
103    fn from(value: Value) -> Self {
104        value.with_empty_span()
105    }
106}
107
108impl From<ValueWithSpan> for Value {
109    fn from(value: ValueWithSpan) -> Self {
110        value.value
111    }
112}
113
114/// Primitive SQL values such as number and string
115#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
116#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
117#[cfg_attr(
118    feature = "visitor",
119    derive(Visit, VisitMut),
120    visit(with = "visit_value")
121)]
122pub enum Value {
123    /// Numeric literal
124    #[cfg(not(feature = "bigdecimal"))]
125    Number(String, bool),
126    #[cfg(feature = "bigdecimal")]
127    /// HINT: use `test_utils::number` to make an instance of
128    /// Value::Number This might help if you your tests pass locally
129    /// but fail on CI with the `--all-features` flag enabled
130    /// Numeric literal (uses `BigDecimal` when the `bigdecimal` feature is enabled).
131    Number(BigDecimal, bool),
132    /// 'string value'
133    SingleQuotedString(String),
134    /// Dollar-quoted string literal, e.g. `$$...$$` or `$tag$...$tag$` (Postgres syntax).
135    DollarQuotedString(DollarQuotedString),
136    /// Triple single quoted strings: Example '''abc'''
137    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
138    TripleSingleQuotedString(String),
139    /// Triple double quoted strings: Example """abc"""
140    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
141    TripleDoubleQuotedString(String),
142    /// e'string value' (postgres extension)
143    /// See [Postgres docs](https://www.postgresql.org/docs/8.3/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS)
144    /// for more details.
145    EscapedStringLiteral(String),
146    /// u&'string value' (postgres extension)
147    /// See [Postgres docs](https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-UESCAPE)
148    /// for more details.
149    UnicodeStringLiteral(String),
150    /// B'string value'
151    SingleQuotedByteStringLiteral(String),
152    /// B"string value"
153    DoubleQuotedByteStringLiteral(String),
154    /// Triple single quoted literal with byte string prefix. Example `B'''abc'''`
155    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
156    TripleSingleQuotedByteStringLiteral(String),
157    /// Triple double quoted literal with byte string prefix. Example `B"""abc"""`
158    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
159    TripleDoubleQuotedByteStringLiteral(String),
160    /// Single quoted literal with raw string prefix. Example `R'abc'`
161    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
162    SingleQuotedRawStringLiteral(String),
163    /// Double quoted literal with raw string prefix. Example `R"abc"`
164    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
165    DoubleQuotedRawStringLiteral(String),
166    /// Triple single quoted literal with raw string prefix. Example `R'''abc'''`
167    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
168    TripleSingleQuotedRawStringLiteral(String),
169    /// Triple double quoted literal with raw string prefix. Example `R"""abc"""`
170    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
171    TripleDoubleQuotedRawStringLiteral(String),
172    /// N'string value'
173    NationalStringLiteral(String),
174    /// Quote delimited literal. Examples `Q'{ab'c}'`, `Q'|ab'c|'`, `Q'|ab|c|'`
175    /// [Oracle](https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/Literals.html#GUID-1824CBAA-6E16-4921-B2A6-112FB02248DA)
176    QuoteDelimitedStringLiteral(QuoteDelimitedString),
177    /// "National" quote delimited literal. Examples `Q'{ab'c}'`, `Q'|ab'c|'`, `Q'|ab|c|'`
178    /// [Oracle](https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/Literals.html#GUID-1824CBAA-6E16-4921-B2A6-112FB02248DA)
179    NationalQuoteDelimitedStringLiteral(QuoteDelimitedString),
180    /// X'hex value'
181    HexStringLiteral(String),
182
183    /// Double quoted string literal, e.g. `"abc"`.
184    DoubleQuotedString(String),
185    /// Boolean value true or false
186    Boolean(bool),
187    /// `NULL` value
188    Null,
189    /// `?` or `$` Prepared statement arg placeholder
190    Placeholder(String),
191}
192
193impl ValueWithSpan {
194    /// If the underlying literal is a string, regardless of quote style, returns the associated string value
195    pub fn into_string(self) -> Option<String> {
196        self.value.into_string()
197    }
198}
199
200impl Value {
201    /// If the underlying literal is a string, regardless of quote style, returns the associated string value
202    pub fn into_string(self) -> Option<String> {
203        match self {
204            Value::SingleQuotedString(s)
205            | Value::DoubleQuotedString(s)
206            | Value::TripleSingleQuotedString(s)
207            | Value::TripleDoubleQuotedString(s)
208            | Value::SingleQuotedByteStringLiteral(s)
209            | Value::DoubleQuotedByteStringLiteral(s)
210            | Value::TripleSingleQuotedByteStringLiteral(s)
211            | Value::TripleDoubleQuotedByteStringLiteral(s)
212            | Value::SingleQuotedRawStringLiteral(s)
213            | Value::DoubleQuotedRawStringLiteral(s)
214            | Value::TripleSingleQuotedRawStringLiteral(s)
215            | Value::TripleDoubleQuotedRawStringLiteral(s)
216            | Value::EscapedStringLiteral(s)
217            | Value::UnicodeStringLiteral(s)
218            | Value::NationalStringLiteral(s)
219            | Value::HexStringLiteral(s) => Some(s),
220            Value::DollarQuotedString(s) => Some(s.value),
221            Value::QuoteDelimitedStringLiteral(s) => Some(s.value),
222            Value::NationalQuoteDelimitedStringLiteral(s) => Some(s.value),
223            _ => None,
224        }
225    }
226
227    /// Attach the provided `span` to this `Value` and return `ValueWithSpan`.
228    pub fn with_span(self, span: Span) -> ValueWithSpan {
229        ValueWithSpan { value: self, span }
230    }
231
232    /// Convenience for attaching an empty span to this `Value`.
233    pub fn with_empty_span(self) -> ValueWithSpan {
234        self.with_span(Span::empty())
235    }
236}
237
238impl fmt::Display for ValueWithSpan {
239    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
240        write!(f, "{}", self.value)
241    }
242}
243
244impl fmt::Display for Value {
245    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
246        match self {
247            Value::Number(v, l) => write!(f, "{}{long}", v, long = if *l { "L" } else { "" }),
248            Value::DoubleQuotedString(v) => write!(f, "\"{}\"", escape_double_quote_string(v)),
249            Value::SingleQuotedString(v) => write!(f, "'{}'", escape_single_quote_string(v)),
250            Value::TripleSingleQuotedString(v) => {
251                write!(f, "'''{v}'''")
252            }
253            Value::TripleDoubleQuotedString(v) => {
254                write!(f, r#""""{v}""""#)
255            }
256            Value::DollarQuotedString(v) => write!(f, "{v}"),
257            Value::EscapedStringLiteral(v) => write!(f, "E'{}'", escape_escaped_string(v)),
258            Value::UnicodeStringLiteral(v) => write!(f, "U&'{}'", escape_unicode_string(v)),
259            Value::NationalStringLiteral(v) => write!(f, "N'{v}'"),
260            Value::QuoteDelimitedStringLiteral(v) => v.fmt(f),
261            Value::NationalQuoteDelimitedStringLiteral(v) => write!(f, "N{v}"),
262            Value::HexStringLiteral(v) => write!(f, "X'{v}'"),
263            Value::Boolean(v) => write!(f, "{v}"),
264            Value::SingleQuotedByteStringLiteral(v) => write!(f, "B'{v}'"),
265            Value::DoubleQuotedByteStringLiteral(v) => write!(f, "B\"{v}\""),
266            Value::TripleSingleQuotedByteStringLiteral(v) => write!(f, "B'''{v}'''"),
267            Value::TripleDoubleQuotedByteStringLiteral(v) => write!(f, r#"B"""{v}""""#),
268            Value::SingleQuotedRawStringLiteral(v) => write!(f, "R'{v}'"),
269            Value::DoubleQuotedRawStringLiteral(v) => write!(f, "R\"{v}\""),
270            Value::TripleSingleQuotedRawStringLiteral(v) => write!(f, "R'''{v}'''"),
271            Value::TripleDoubleQuotedRawStringLiteral(v) => write!(f, r#"R"""{v}""""#),
272            Value::Null => write!(f, "NULL"),
273            Value::Placeholder(v) => write!(f, "{v}"),
274        }
275    }
276}
277
278/// A dollar-quoted string literal, e.g. `$$...$$` or `$tag$...$tag$`.
279#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
280#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
281#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
282pub struct DollarQuotedString {
283    /// Inner string contents.
284    pub value: String,
285    /// Optional tag used in the opening/closing delimiter.
286    pub tag: Option<String>,
287}
288
289impl fmt::Display for DollarQuotedString {
290    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
291        match &self.tag {
292            Some(tag) => {
293                write!(f, "${}${}${}$", tag, self.value, tag)
294            }
295            None => {
296                write!(f, "$${}$$", self.value)
297            }
298        }
299    }
300}
301
302/// A quote delimited string literal, e.g. `Q'_abc_'`.
303///
304/// See [Value::QuoteDelimitedStringLiteral] and/or
305/// [Value::NationalQuoteDelimitedStringLiteral].
306#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
307#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
308#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
309pub struct QuoteDelimitedString {
310    /// the quote start character; i.e. the character _after_ the opening `Q'`
311    pub start_quote: char,
312    /// the string literal value itself
313    pub value: String,
314    /// the quote end character; i.e. the character _before_ the closing `'`
315    pub end_quote: char,
316}
317
318impl fmt::Display for QuoteDelimitedString {
319    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
320        write!(f, "Q'{}{}{}'", self.start_quote, self.value, self.end_quote)
321    }
322}
323
324/// Represents the date/time fields used by functions like `EXTRACT`.
325///
326/// Each variant corresponds to a supported date/time part (for example
327/// `YEAR`, `MONTH`, `DAY`, etc.). The `Custom` variant allows arbitrary
328/// identifiers (e.g. dialect-specific abbreviations).
329#[derive(Debug, Clone, PartialEq, Eq, Ord, PartialOrd, Hash)]
330#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
331#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
332pub enum DateTimeField {
333    /// `YEAR`
334    Year,
335    /// `YEARS` (plural form)
336    Years,
337    /// `MONTH`
338    Month,
339    /// `MONTHS` (plural form)
340    Months,
341    /// `WEEK`, optionally followed by a weekday, e.g. `WEEK(MONDAY)`.
342    ///
343    /// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/date_functions#extract)
344    Week(Option<Ident>),
345    /// `WEEKS` (plural form)
346    Weeks,
347    /// `DAY`
348    Day,
349    /// `DAYOFWEEK`
350    DayOfWeek,
351    /// `DAYOFYEAR`
352    DayOfYear,
353    /// `DAYS` (plural form)
354    Days,
355    /// `DATE`
356    Date,
357    /// `DATETIME`
358    Datetime,
359    /// `HOUR`
360    Hour,
361    /// `HOURS` (plural form)
362    Hours,
363    /// `MINUTE`
364    Minute,
365    /// `MINUTES` (plural form)
366    Minutes,
367    /// `SECOND`
368    Second,
369    /// `SECONDS` (plural form)
370    Seconds,
371    /// `CENTURY`
372    Century,
373    /// `DECADE`
374    Decade,
375    /// `DOW` (day of week short form)
376    Dow,
377    /// `DOY` (day of year short form)
378    Doy,
379    /// `EPOCH`
380    Epoch,
381    /// `ISODOW`
382    Isodow,
383    /// `ISOYEAR`
384    Isoyear,
385    /// `ISOWEEK`
386    IsoWeek,
387    /// `JULIAN`
388    Julian,
389    /// `MICROSECOND`
390    Microsecond,
391    /// `MICROSECONDS` (plural form)
392    Microseconds,
393    /// `MILLENIUM` (alternate spelling)
394    Millenium,
395    /// `MILLENNIUM` (alternate spelling)
396    Millennium,
397    /// `MILLISECOND`
398    Millisecond,
399    /// `MILLISECONDS` (plural form)
400    Milliseconds,
401    /// `NANOSECOND`
402    Nanosecond,
403    /// `NANOSECONDS` (plural form)
404    Nanoseconds,
405    /// `QUARTER`
406    Quarter,
407    /// `TIME`
408    Time,
409    /// `TIMEZONE`
410    Timezone,
411    /// `TIMEZONE_ABBR`
412    TimezoneAbbr,
413    /// `TIMEZONE_HOUR`
414    TimezoneHour,
415    /// `TIMEZONE_MINUTE`
416    TimezoneMinute,
417    /// `TIMEZONE_REGION`
418    TimezoneRegion,
419    /// `NODATETIME` indicates no date/time part
420    NoDateTime,
421    /// Arbitrary abbreviation or custom date-time part.
422    ///
423    /// ```sql
424    /// EXTRACT(q FROM CURRENT_TIMESTAMP)
425    /// ```
426    /// [Snowflake](https://docs.snowflake.com/en/sql-reference/functions-date-time#supported-date-and-time-parts)
427    Custom(Ident),
428}
429
430impl fmt::Display for DateTimeField {
431    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
432        match self {
433            DateTimeField::Year => write!(f, "YEAR"),
434            DateTimeField::Years => write!(f, "YEARS"),
435            DateTimeField::Month => write!(f, "MONTH"),
436            DateTimeField::Months => write!(f, "MONTHS"),
437            DateTimeField::Week(week_day) => {
438                write!(f, "WEEK")?;
439                if let Some(week_day) = week_day {
440                    write!(f, "({week_day})")?
441                }
442                Ok(())
443            }
444            DateTimeField::Weeks => write!(f, "WEEKS"),
445            DateTimeField::Day => write!(f, "DAY"),
446            DateTimeField::DayOfWeek => write!(f, "DAYOFWEEK"),
447            DateTimeField::DayOfYear => write!(f, "DAYOFYEAR"),
448            DateTimeField::Days => write!(f, "DAYS"),
449            DateTimeField::Date => write!(f, "DATE"),
450            DateTimeField::Datetime => write!(f, "DATETIME"),
451            DateTimeField::Hour => write!(f, "HOUR"),
452            DateTimeField::Hours => write!(f, "HOURS"),
453            DateTimeField::Minute => write!(f, "MINUTE"),
454            DateTimeField::Minutes => write!(f, "MINUTES"),
455            DateTimeField::Second => write!(f, "SECOND"),
456            DateTimeField::Seconds => write!(f, "SECONDS"),
457            DateTimeField::Century => write!(f, "CENTURY"),
458            DateTimeField::Decade => write!(f, "DECADE"),
459            DateTimeField::Dow => write!(f, "DOW"),
460            DateTimeField::Doy => write!(f, "DOY"),
461            DateTimeField::Epoch => write!(f, "EPOCH"),
462            DateTimeField::Isodow => write!(f, "ISODOW"),
463            DateTimeField::Isoyear => write!(f, "ISOYEAR"),
464            DateTimeField::IsoWeek => write!(f, "ISOWEEK"),
465            DateTimeField::Julian => write!(f, "JULIAN"),
466            DateTimeField::Microsecond => write!(f, "MICROSECOND"),
467            DateTimeField::Microseconds => write!(f, "MICROSECONDS"),
468            DateTimeField::Millenium => write!(f, "MILLENIUM"),
469            DateTimeField::Millennium => write!(f, "MILLENNIUM"),
470            DateTimeField::Millisecond => write!(f, "MILLISECOND"),
471            DateTimeField::Milliseconds => write!(f, "MILLISECONDS"),
472            DateTimeField::Nanosecond => write!(f, "NANOSECOND"),
473            DateTimeField::Nanoseconds => write!(f, "NANOSECONDS"),
474            DateTimeField::Quarter => write!(f, "QUARTER"),
475            DateTimeField::Time => write!(f, "TIME"),
476            DateTimeField::Timezone => write!(f, "TIMEZONE"),
477            DateTimeField::TimezoneAbbr => write!(f, "TIMEZONE_ABBR"),
478            DateTimeField::TimezoneHour => write!(f, "TIMEZONE_HOUR"),
479            DateTimeField::TimezoneMinute => write!(f, "TIMEZONE_MINUTE"),
480            DateTimeField::TimezoneRegion => write!(f, "TIMEZONE_REGION"),
481            DateTimeField::NoDateTime => write!(f, "NODATETIME"),
482            DateTimeField::Custom(custom) => write!(f, "{custom}"),
483        }
484    }
485}
486
487#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
488#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
489#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
490/// The Unicode Standard defines four normalization forms, which are intended to eliminate
491/// certain distinctions between visually or functionally identical characters.
492///
493/// See [Unicode Normalization Forms](https://unicode.org/reports/tr15/) for details.
494pub enum NormalizationForm {
495    /// Canonical Decomposition, followed by Canonical Composition.
496    NFC,
497    /// Canonical Decomposition.
498    NFD,
499    /// Compatibility Decomposition, followed by Canonical Composition.
500    NFKC,
501    /// Compatibility Decomposition.
502    NFKD,
503}
504
505impl fmt::Display for NormalizationForm {
506    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
507        match self {
508            NormalizationForm::NFC => write!(f, "NFC"),
509            NormalizationForm::NFD => write!(f, "NFD"),
510            NormalizationForm::NFKC => write!(f, "NFKC"),
511            NormalizationForm::NFKD => write!(f, "NFKD"),
512        }
513    }
514}
515
516pub struct EscapeQuotedString<'a> {
517    string: &'a str,
518    quote: char,
519}
520
521impl fmt::Display for EscapeQuotedString<'_> {
522    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
523        // EscapeQuotedString doesn't know which mode of escape was
524        // chosen by the user. So this code must to correctly display
525        // strings without knowing if the strings are already escaped
526        // or not.
527        //
528        // If the quote symbol in the string is repeated twice, OR, if
529        // the quote symbol is after backslash, display all the chars
530        // without any escape. However, if the quote symbol is used
531        // just between usual chars, `fmt()` should display it twice."
532        //
533        // The following table has examples
534        //
535        // | original query | mode      | AST Node                                           | serialized   |
536        // | -------------  | --------- | -------------------------------------------------- | ------------ |
537        // | `"A""B""A"`    | no-escape | `DoubleQuotedString(String::from("A\"\"B\"\"A"))`  | `"A""B""A"`  |
538        // | `"A""B""A"`    | default   | `DoubleQuotedString(String::from("A\"B\"A"))`      | `"A""B""A"`  |
539        // | `"A\"B\"A"`    | no-escape | `DoubleQuotedString(String::from("A\\\"B\\\"A"))`  | `"A\"B\"A"`  |
540        // | `"A\"B\"A"`    | default   | `DoubleQuotedString(String::from("A\"B\"A"))`      | `"A""B""A"`  |
541        let quote = self.quote;
542        let mut previous_char = char::default();
543        let mut start_idx = 0;
544        let mut peekable_chars = self.string.char_indices().peekable();
545        while let Some(&(idx, ch)) = peekable_chars.peek() {
546            match ch {
547                char if char == quote => {
548                    if previous_char == '\\' {
549                        // the quote is already escaped with a backslash, skip
550                        peekable_chars.next();
551                        continue;
552                    }
553                    peekable_chars.next();
554                    match peekable_chars.peek() {
555                        Some((_, c)) if *c == quote => {
556                            // the quote is already escaped with another quote, skip
557                            peekable_chars.next();
558                        }
559                        _ => {
560                            // The quote is not escaped.
561                            // Including idx in the range, so the quote at idx will be printed twice:
562                            // in this call to write_str() and in the next one.
563                            f.write_str(&self.string[start_idx..=idx])?;
564                            start_idx = idx;
565                        }
566                    }
567                }
568                _ => {
569                    peekable_chars.next();
570                }
571            }
572            previous_char = ch;
573        }
574        f.write_str(&self.string[start_idx..])?;
575        Ok(())
576    }
577}
578
579/// Return a helper which formats `string` for inclusion inside a quoted
580/// literal that uses `quote` as the delimiter.
581pub fn escape_quoted_string(string: &str, quote: char) -> EscapeQuotedString<'_> {
582    EscapeQuotedString { string, quote }
583}
584
585/// Convenience wrapper for escaping strings for single-quoted literals (`'`).
586pub fn escape_single_quote_string(s: &str) -> EscapeQuotedString<'_> {
587    escape_quoted_string(s, '\'')
588}
589
590/// Convenience wrapper for escaping strings for double-quoted literals (`").`
591pub fn escape_double_quote_string(s: &str) -> EscapeQuotedString<'_> {
592    escape_quoted_string(s, '\"')
593}
594
595pub struct EscapeEscapedStringLiteral<'a>(&'a str);
596
597impl fmt::Display for EscapeEscapedStringLiteral<'_> {
598    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
599        for c in self.0.chars() {
600            match c {
601                '\'' => {
602                    write!(f, r#"\'"#)?;
603                }
604                '\\' => {
605                    write!(f, r#"\\"#)?;
606                }
607                '\n' => {
608                    write!(f, r#"\n"#)?;
609                }
610                '\t' => {
611                    write!(f, r#"\t"#)?;
612                }
613                '\r' => {
614                    write!(f, r#"\r"#)?;
615                }
616                _ => {
617                    write!(f, "{c}")?;
618                }
619            }
620        }
621        Ok(())
622    }
623}
624
625/// Return a helper which escapes characters for string literals that use
626/// PostgreSQL-style escaped string literals (e.g. `E'...')`.
627pub fn escape_escaped_string(s: &str) -> EscapeEscapedStringLiteral<'_> {
628    EscapeEscapedStringLiteral(s)
629}
630
631pub struct EscapeUnicodeStringLiteral<'a>(&'a str);
632
633impl fmt::Display for EscapeUnicodeStringLiteral<'_> {
634    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
635        for c in self.0.chars() {
636            match c {
637                '\'' => {
638                    write!(f, "''")?;
639                }
640                '\\' => {
641                    write!(f, r#"\\"#)?;
642                }
643                x if x.is_ascii() => {
644                    write!(f, "{c}")?;
645                }
646                _ => {
647                    let codepoint = c as u32;
648                    // if the character fits in 32 bits, we can use the \XXXX format
649                    // otherwise, we need to use the \+XXXXXX format
650                    if codepoint <= 0xFFFF {
651                        write!(f, "\\{codepoint:04X}")?;
652                    } else {
653                        write!(f, "\\+{codepoint:06X}")?;
654                    }
655                }
656            }
657        }
658        Ok(())
659    }
660}
661
662/// Return a helper which escapes non-ASCII characters using `\XXXX` or
663/// `\+XXXXXX` Unicode escape formats (used for `U&'...'` style literals).
664pub fn escape_unicode_string(s: &str) -> EscapeUnicodeStringLiteral<'_> {
665    EscapeUnicodeStringLiteral(s)
666}
667
668/// The side on which `TRIM` should be applied.
669///
670/// Corresponds to `TRIM(BOTH|LEADING|TRAILING)` SQL syntax.
671#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
672#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
673#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
674pub enum TrimWhereField {
675    /// `BOTH` (trim from both ends)
676    Both,
677    /// `LEADING` (trim from start)
678    Leading,
679    /// `TRAILING` (trim from end)
680    Trailing,
681}
682
683impl fmt::Display for TrimWhereField {
684    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
685        use TrimWhereField::*;
686        f.write_str(match self {
687            Both => "BOTH",
688            Leading => "LEADING",
689            Trailing => "TRAILING",
690        })
691    }
692}