zero_postgres/state/
action.rs

1//! Action types for state machine I/O requests.
2
3use crate::error::ServerError;
4
5/// Action requested by a state machine.
6///
7/// The caller should perform the requested I/O and then call the
8/// appropriate method to continue the state machine.
9#[derive(Debug)]
10pub enum Action {
11    /// Write `buffer_set.write_buffer` to the server, then read a single byte.
12    ///
13    /// Used for SSL negotiation: write SSL request, then read response ('S' or 'N').
14    WriteAndReadByte,
15
16    /// Read a PostgreSQL message from the server.
17    ///
18    /// The caller should:
19    /// 1. Read the message type byte (1 byte)
20    /// 2. Read the length (4 bytes, big-endian i32)
21    /// 3. Read (length - 4) bytes of payload into the buffer set
22    /// 4. Call the state machine's `step()` method again
23    ReadMessage,
24
25    /// Write `buffer_set.write_buffer` to the server.
26    ///
27    /// The caller should write all bytes to the socket and flush,
28    /// then call `step()` again.
29    Write,
30
31    /// Write `buffer_set.write_buffer` to the server, then read a message.
32    ///
33    /// Used for query operations: write query, then read response.
34    WriteAndReadMessage,
35
36    /// Perform TLS handshake.
37    ///
38    /// After successful handshake, call `step()` again.
39    TlsHandshake,
40
41    /// An asynchronous message was received.
42    ///
43    /// The caller should handle the message, read the next message,
44    /// then call `step()` again.
45    HandleAsyncMessageAndReadMessage(AsyncMessage),
46
47    /// The state machine has finished successfully.
48    Finished,
49}
50
51/// Asynchronous message from the server.
52///
53/// These can arrive at any time during query execution.
54#[derive(Debug, Clone)]
55pub enum AsyncMessage {
56    /// Notification from LISTEN/NOTIFY.
57    Notification {
58        /// PID of the notifying backend process
59        pid: u32,
60        /// Channel name
61        channel: String,
62        /// Notification payload
63        payload: String,
64    },
65
66    /// Non-fatal notice/warning from server.
67    Notice(ServerError),
68
69    /// Server parameter value changed.
70    ParameterChanged {
71        /// Parameter name
72        name: String,
73        /// New value
74        value: String,
75    },
76}
zero_postgres/state/action.rs

zero_postgres/state/
action.rs
