narwhal_core/
capabilities.rs

1use serde::{Deserialize, Serialize};
2
3/// Static description of features a driver supports.
4///
5/// The UI inspects [`Capabilities`] to enable or disable commands without
6/// hard-coding driver names. New flags are added by extending this struct;
7/// existing drivers default to `false` for unknown features.
8#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
9#[non_exhaustive]
10pub struct Capabilities {
11    /// Driver supports explicit transactions (`BEGIN`/`COMMIT`/`ROLLBACK`).
12    pub transactions: bool,
13    /// Driver can request asynchronous cancellation of an in-flight query.
14    pub cancellation: bool,
15    /// Driver exposes more than one logical schema/namespace.
16    pub multiple_schemas: bool,
17    /// Driver supports server-side prepared statements with parameter binding.
18    pub prepared_statements: bool,
19    /// Driver supports nested transactions via savepoints.
20    pub savepoints: bool,
21    /// Driver can report row counts for `UPDATE`/`DELETE` statements.
22    pub rows_affected: bool,
23    /// Driver returns rows progressively from [`crate::Connection::stream`] —
24    /// i.e. the stream yields rows as the server produces them, without
25    /// materialising the entire result set in memory first.
26    ///
27    /// Drivers that currently buffer the full result before exposing the
28    /// stream (notably `MySQL`, which is awaiting a real `stream_and_drop`
29    /// implementation) must leave this `false` so the UI can warn the
30    /// user and refuse to launch open-ended streams over large tables.
31    pub streaming: bool,
32    /// Driver supports row-level DML through the standard
33    /// `INSERT`/`UPDATE`/`DELETE` grammar that
34    /// [`crate::Connection::execute`] accepts.
35    ///
36    /// Most engines do; the notable exception is `ClickHouse`, where
37    /// row-level changes have to go through `ALTER TABLE ... UPDATE`
38    /// or `ALTER TABLE ... DELETE` async mutations. The pending-changes
39    /// pipeline gates `o`/`O`/`d`/cell-edit on this flag so it never
40    /// emits a statement the driver cannot consume. Defaults to
41    /// `false`; drivers opt in explicitly via
42    /// [`Self::with_row_level_dml`].
43    pub row_level_dml: bool,
44}
45
46impl Capabilities {
47    /// Builder-style mutation used by drivers to assemble their capability set.
48    #[must_use]
49    pub const fn with_transactions(mut self, value: bool) -> Self {
50        self.transactions = value;
51        self
52    }
53
54    #[must_use]
55    pub const fn with_cancellation(mut self, value: bool) -> Self {
56        self.cancellation = value;
57        self
58    }
59
60    #[must_use]
61    pub const fn with_multiple_schemas(mut self, value: bool) -> Self {
62        self.multiple_schemas = value;
63        self
64    }
65
66    #[must_use]
67    pub const fn with_prepared_statements(mut self, value: bool) -> Self {
68        self.prepared_statements = value;
69        self
70    }
71
72    #[must_use]
73    pub const fn with_savepoints(mut self, value: bool) -> Self {
74        self.savepoints = value;
75        self
76    }
77
78    #[must_use]
79    pub const fn with_rows_affected(mut self, value: bool) -> Self {
80        self.rows_affected = value;
81        self
82    }
83
84    #[must_use]
85    pub const fn with_streaming(mut self, value: bool) -> Self {
86        self.streaming = value;
87        self
88    }
89
90    #[must_use]
91    pub const fn with_row_level_dml(mut self, value: bool) -> Self {
92        self.row_level_dml = value;
93        self
94    }
95}
narwhal_core/capabilities.rs

narwhal_core/
capabilities.rs
