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

// Copyright 2023 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use sqlx::postgres::PgQueryResult;
use thiserror::Error;
use ulid::Ulid;

/// Generic error when interacting with the database
#[derive(Debug, Error)]
#[error(transparent)]
pub enum DatabaseError {
    /// An error which came from the database itself
    Driver {
        /// The underlying error from the database driver
        #[from]
        source: sqlx::Error,
    },

    /// An error which occured while converting the data from the database
    Inconsistency(#[from] DatabaseInconsistencyError),

    /// An error which happened because the requested database operation is
    /// invalid
    #[error("Invalid database operation")]
    InvalidOperation {
        /// The source of the error, if any
        #[source]
        source: Option<Box<dyn std::error::Error + Send + Sync + 'static>>,
    },

    /// An error which happens when an operation affects not enough or too many
    /// rows
    #[error("Expected {expected} rows to be affected, but {actual} rows were affected")]
    RowsAffected {
        /// How many rows were expected to be affected
        expected: u64,

        /// How many rows were actually affected
        actual: u64,
    },
}

impl DatabaseError {
    pub(crate) fn ensure_affected_rows(
        result: &PgQueryResult,
        expected: u64,
    ) -> Result<(), DatabaseError> {
        let actual = result.rows_affected();
        if actual == expected {
            Ok(())
        } else {
            Err(DatabaseError::RowsAffected { expected, actual })
        }
    }

    pub(crate) fn to_invalid_operation<E: std::error::Error + Send + Sync + 'static>(e: E) -> Self {
        Self::InvalidOperation {
            source: Some(Box::new(e)),
        }
    }

    pub(crate) const fn invalid_operation() -> Self {
        Self::InvalidOperation { source: None }
    }
}

/// An error which occured while converting the data from the database
#[derive(Debug, Error)]
pub struct DatabaseInconsistencyError {
    /// The table which was being queried
    table: &'static str,

    /// The column which was being queried
    column: Option<&'static str>,

    /// The row which was being queried
    row: Option<Ulid>,

    /// The source of the error
    #[source]
    source: Option<Box<dyn std::error::Error + Send + Sync + 'static>>,
}

impl std::fmt::Display for DatabaseInconsistencyError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Database inconsistency on table {}", self.table)?;
        if let Some(column) = self.column {
            write!(f, " column {column}")?;
        }
        if let Some(row) = self.row {
            write!(f, " row {row}")?;
        }

        Ok(())
    }
}

impl DatabaseInconsistencyError {
    /// Create a new [`DatabaseInconsistencyError`] for the given table
    #[must_use]
    pub(crate) const fn on(table: &'static str) -> Self {
        Self {
            table,
            column: None,
            row: None,
            source: None,
        }
    }

    /// Set the column which was being queried
    #[must_use]
    pub(crate) const fn column(mut self, column: &'static str) -> Self {
        self.column = Some(column);
        self
    }

    /// Set the row which was being queried
    #[must_use]
    pub(crate) const fn row(mut self, row: Ulid) -> Self {
        self.row = Some(row);
        self
    }

    /// Give the source of the error
    #[must_use]
    pub(crate) fn source<E: std::error::Error + Send + Sync + 'static>(
        mut self,
        source: E,
    ) -> Self {
        self.source = Some(Box::new(source));
        self
    }
}