uqa_sql/compiler/
dispatch.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! Parser entry point and exhaustive statement-family dispatch.
8
9use super::administrative::{
10    compile_analyze, compile_explain, compile_set_constraints, compile_transaction,
11    compile_truncate, compile_variable_set, discard_target,
12};
13use super::cursors::{compile_close_cursor, compile_declare_cursor, compile_fetch_cursor};
14use super::dml::{compile_delete, compile_update};
15use super::drop_alter::{
16    compile_alter_object_schema, compile_alter_table, compile_drop, compile_rename,
17};
18use super::events::{compile_create_rule, compile_create_trigger};
19use super::merge::compile_merge;
20use super::relations::{
21    compile_create_foreign_server, compile_create_foreign_table, compile_create_schema,
22    compile_create_table_as, compile_create_view, compile_deallocate, compile_execute,
23    compile_prepare, compile_refresh_materialized_view, compile_top_level_select,
24    defer_create_foreign_table, defer_create_table,
25};
26use super::routines::{
27    compile_alter_role, compile_alter_routine, compile_alter_routine_owner, compile_call,
28    compile_create_function, compile_create_role, compile_do, compile_drop_role, compile_grant,
29    compile_grant_role,
30};
31use super::sequences::{compile_alter_sequence, compile_create_sequence};
32use super::{
33    compile_create_index, compile_create_table, compile_insert, compile_values_lists, Node,
34    NodeEnum, Result, SQLError, Statement,
35};
36
37/// A syntactically valid statement retaining its exact source slice. Compilation is separate so an execution boundary can analyze statements in order after preceding commands have completed.
38#[derive(Debug, Clone)]
39pub struct ParsedStatement<'sql> {
40    sql: &'sql str,
41    node: Box<Node>,
42}
43
44impl<'sql> ParsedStatement<'sql> {
45    /// Original SQL, without reconstructing or rewriting the parser tree.
46    pub const fn sql(&self) -> &'sql str {
47        self.sql
48    }
49
50    /// Compile this statement into the engine's internal SQL representation.
51    pub fn compile(&self) -> Result<Statement> {
52        compile_stmt(&self.node)
53    }
54}
55
56/// Parse an entire SQL message before exposing any statement for execution. `PostgreSQL` syntax errors reject the whole message; semantic compilation errors can be surfaced later, at the affected statement's boundary.
57pub fn parse_statements(sql: &str) -> Result<Vec<ParsedStatement<'_>>> {
58    let parsed = pg_query::parse(sql)?;
59    let mut out = Vec::with_capacity(parsed.protobuf.stmts.len());
60    for raw in parsed.protobuf.stmts {
61        let node = raw
62            .stmt
63            .ok_or_else(|| SQLError::Internal("parser returned an empty statement".into()))?;
64        let start = usize::try_from(raw.stmt_location).map_err(|_| {
65            SQLError::Internal("parser returned a negative statement offset".into())
66        })?;
67        let end = if raw.stmt_len == 0 {
68            sql.len()
69        } else {
70            let len = usize::try_from(raw.stmt_len).map_err(|_| {
71                SQLError::Internal("parser returned a negative statement length".into())
72            })?;
73            start
74                .checked_add(len)
75                .ok_or_else(|| SQLError::Internal("parser statement offset overflow".into()))?
76        };
77        let source = sql.get(start..end).ok_or_else(|| {
78            SQLError::Internal("parser statement bounds do not match SQL text".into())
79        })?;
80        out.push(ParsedStatement { sql: source, node });
81    }
82    Ok(out)
83}
84
85pub fn compile(sql: &str) -> Result<Vec<Statement>> {
86    parse_statements(sql)?
87        .iter()
88        .map(ParsedStatement::compile)
89        .collect()
90}
91
92pub fn resolve_deferred_create_table(
93    deferred: &crate::ast::DeferredCreateTable,
94) -> Result<crate::ast::CreateTable> {
95    let parsed = pg_query::parse(&deferred.definition_sql)?;
96    let [raw] = parsed.protobuf.stmts.as_slice() else {
97        return Err(SQLError::Internal(
98            "deferred CREATE TABLE did not contain exactly one statement".into(),
99        ));
100    };
101    let node = raw
102        .stmt
103        .as_deref()
104        .and_then(|node| node.node.as_ref())
105        .ok_or_else(|| SQLError::Internal("deferred CREATE TABLE is empty".into()))?;
106    let NodeEnum::CreateStmt(stmt) = node else {
107        return Err(SQLError::Internal(
108            "deferred CREATE TABLE changed statement kind".into(),
109        ));
110    };
111    let table = compile_create_table(stmt)?;
112    if !table.if_not_exists
113        || table.name != deferred.name
114        || table.persistence != deferred.persistence
115    {
116        return Err(SQLError::Internal(
117            "deferred CREATE TABLE changed target identity".into(),
118        ));
119    }
120    Ok(table)
121}
122
123pub fn resolve_deferred_create_foreign_table(
124    deferred: &crate::ast::DeferredCreateForeignTable,
125) -> Result<crate::ast::CreateForeignTable> {
126    let parsed = pg_query::parse(&deferred.definition_sql)?;
127    let [raw] = parsed.protobuf.stmts.as_slice() else {
128        return Err(SQLError::Internal(
129            "deferred CREATE FOREIGN TABLE did not contain exactly one statement".into(),
130        ));
131    };
132    let node = raw
133        .stmt
134        .as_deref()
135        .and_then(|node| node.node.as_ref())
136        .ok_or_else(|| SQLError::Internal("deferred CREATE FOREIGN TABLE is empty".into()))?;
137    let NodeEnum::CreateForeignTableStmt(stmt) = node else {
138        return Err(SQLError::Internal(
139            "deferred CREATE FOREIGN TABLE changed statement kind".into(),
140        ));
141    };
142    let table = compile_create_foreign_table(stmt)?;
143    if !table.if_not_exists
144        || table.name != deferred.name
145        || table.server_name != deferred.server_name
146    {
147        return Err(SQLError::Internal(
148            "deferred CREATE FOREIGN TABLE changed target identity".into(),
149        ));
150    }
151    Ok(table)
152}
153
154fn compile_create_table_statement(statement: &pg_query::protobuf::CreateStmt) -> Result<Statement> {
155    if statement.if_not_exists {
156        defer_create_table(statement).map(Statement::CreateTableIfNotExists)
157    } else {
158        compile_create_table(statement).map(Statement::CreateTable)
159    }
160}
161
162fn compile_create_foreign_table_statement(
163    statement: &pg_query::protobuf::CreateForeignTableStmt,
164) -> Result<Statement> {
165    if statement
166        .base_stmt
167        .as_ref()
168        .is_some_and(|base| base.if_not_exists)
169    {
170        defer_create_foreign_table(statement).map(Statement::CreateForeignTableIfNotExists)
171    } else {
172        compile_create_foreign_table(statement).map(Statement::CreateForeignTable)
173    }
174}
175
176pub(super) fn compile_stmt(node: &Node) -> Result<Statement> {
177    let Some(inner) = node.node.as_ref() else {
178        return Err(SQLError::Unsupported("empty statement".into()));
179    };
180    match inner {
181        NodeEnum::CreateStmt(stmt) => compile_create_table_statement(stmt),
182        NodeEnum::IndexStmt(stmt) => compile_create_index(stmt).map(Statement::CreateIndex),
183        NodeEnum::InsertStmt(stmt) => compile_insert(stmt).map(Statement::Insert),
184        NodeEnum::SelectStmt(stmt) => {
185            // Standalone `VALUES (...) (...)` parses as a SelectStmt
186            // with empty target_list + populated values_lists. Treat
187            // it as a relation-producing statement directly.
188            if stmt.target_list.is_empty()
189                && !stmt.values_lists.is_empty()
190                && stmt.locking_clause.is_empty()
191                && stmt.sort_clause.is_empty()
192                && stmt.limit_count.is_none()
193                && stmt.limit_offset.is_none()
194            {
195                let rows = compile_values_lists(&stmt.values_lists)?;
196                return Ok(Statement::Values { rows });
197            }
198            compile_top_level_select(stmt)
199        }
200        NodeEnum::UpdateStmt(stmt) => compile_update(stmt).map(Statement::Update),
201        NodeEnum::DeleteStmt(stmt) => compile_delete(stmt).map(Statement::Delete),
202        NodeEnum::DropStmt(stmt) => compile_drop(stmt),
203        NodeEnum::CreateTrigStmt(stmt) => {
204            compile_create_trigger(stmt).map(Statement::CreateTrigger)
205        }
206        NodeEnum::RuleStmt(stmt) => compile_create_rule(stmt).map(Statement::CreateRule),
207        NodeEnum::AlterTableStmt(stmt) => compile_alter_table(stmt),
208        NodeEnum::RenameStmt(stmt) => compile_rename(stmt),
209        NodeEnum::AlterObjectSchemaStmt(stmt) => compile_alter_object_schema(stmt),
210        NodeEnum::ViewStmt(stmt) => compile_create_view(stmt),
211        NodeEnum::CreateSchemaStmt(stmt) => compile_create_schema(stmt),
212        NodeEnum::NotifyStmt(stmt) => Ok(Statement::Notify {
213            channel: stmt.conditionname.clone(),
214            payload: stmt.payload.clone(),
215        }),
216        NodeEnum::ListenStmt(stmt) => Ok(Statement::Listen {
217            channel: stmt.conditionname.clone(),
218        }),
219        NodeEnum::UnlistenStmt(stmt) => Ok(Statement::Unlisten {
220            channel: (!stmt.conditionname.is_empty()).then(|| stmt.conditionname.clone()),
221        }),
222        NodeEnum::ExplainStmt(stmt) => compile_explain(stmt),
223        NodeEnum::VacuumStmt(stmt) => compile_analyze(stmt),
224        NodeEnum::TruncateStmt(stmt) => compile_truncate(stmt),
225        NodeEnum::TransactionStmt(stmt) => compile_transaction(stmt),
226        NodeEnum::DeclareCursorStmt(stmt) => compile_declare_cursor(stmt),
227        NodeEnum::FetchStmt(stmt) => compile_fetch_cursor(stmt),
228        NodeEnum::ClosePortalStmt(stmt) => Ok(compile_close_cursor(stmt)),
229        NodeEnum::CreateSeqStmt(stmt) => {
230            compile_create_sequence(stmt).map(Statement::CreateSequence)
231        }
232        NodeEnum::AlterSeqStmt(stmt) => compile_alter_sequence(stmt).map(Statement::AlterSequence),
233        NodeEnum::CreateTableAsStmt(stmt) => compile_create_table_as(stmt),
234        NodeEnum::RefreshMatViewStmt(stmt) => compile_refresh_materialized_view(stmt),
235        NodeEnum::PrepareStmt(stmt) => compile_prepare(stmt),
236        NodeEnum::ExecuteStmt(stmt) => compile_execute(stmt),
237        NodeEnum::DeallocateStmt(stmt) => compile_deallocate(stmt),
238        NodeEnum::CreateForeignServerStmt(stmt) => {
239            compile_create_foreign_server(stmt).map(Statement::CreateForeignServer)
240        }
241        NodeEnum::CreateForeignTableStmt(stmt) => compile_create_foreign_table_statement(stmt),
242        NodeEnum::MergeStmt(stmt) => compile_merge(stmt).map(Statement::Merge),
243        NodeEnum::CreateDomainStmt(stmt) => {
244            super::domains::compile_create_domain(stmt).map(Statement::CreateDomain)
245        }
246        NodeEnum::CreateFunctionStmt(stmt) => {
247            compile_create_function(stmt).map(|f| Statement::CreateFunction(Box::new(f)))
248        }
249        NodeEnum::DoStmt(stmt) => compile_do(stmt),
250        NodeEnum::CallStmt(stmt) => compile_call(stmt),
251        NodeEnum::AlterFunctionStmt(stmt) => {
252            compile_alter_routine(stmt).map(Statement::AlterRoutine)
253        }
254        NodeEnum::AlterOwnerStmt(stmt) => compile_alter_routine_owner(stmt),
255        NodeEnum::GrantStmt(stmt) => compile_grant(stmt),
256        NodeEnum::GrantRoleStmt(stmt) => compile_grant_role(stmt),
257        NodeEnum::CreateRoleStmt(stmt) => compile_create_role(stmt),
258        NodeEnum::AlterRoleStmt(stmt) => compile_alter_role(stmt),
259        NodeEnum::DropRoleStmt(stmt) => compile_drop_role(stmt),
260        NodeEnum::VariableSetStmt(stmt) => compile_variable_set(stmt),
261        NodeEnum::ConstraintsSetStmt(stmt) => compile_set_constraints(stmt),
262        NodeEnum::VariableShowStmt(stmt) => Ok(Statement::ShowVariable {
263            name: stmt.name.clone(),
264        }),
265        NodeEnum::DiscardStmt(stmt) => Ok(Statement::Discard {
266            target: discard_target(stmt.target)?,
267        }),
268        NodeEnum::LoadStmt(stmt) => Ok(Statement::Load {
269            library: stmt.filename.clone(),
270        }),
271        other => Err(SQLError::Unsupported(format!(
272            "{}",
273            other_node_label(other)
274        ))),
275    }
276}
277
278/// Map `pg_query`'s `DiscardMode` enum (1=ALL, 2=PLANS, 3=SEQUENCES,
279/// 4=TEMP) to the AST's [`DiscardTarget`].
280pub(super) fn other_node_label(node: &NodeEnum) -> &'static str {
281    match node {
282        NodeEnum::ExplainStmt(_) => "EXPLAIN",
283        NodeEnum::ViewStmt(_) => "CREATE VIEW",
284        NodeEnum::TransactionStmt(_) => "BEGIN/COMMIT/ROLLBACK",
285        NodeEnum::DeclareCursorStmt(_) => "DECLARE CURSOR",
286        NodeEnum::FetchStmt(_) => "FETCH/MOVE",
287        NodeEnum::ClosePortalStmt(_) => "CLOSE CURSOR",
288        NodeEnum::PrepareStmt(_) | NodeEnum::ExecuteStmt(_) => "PREPARE/EXECUTE",
289        _ => "unknown statement",
290    }
291}
292
293// -------------------------------------------------------------------------
294// DROP TABLE / DROP INDEX [IF EXISTS] [CASCADE]
295// -------------------------------------------------------------------------
296
297/// Lower `DROP FUNCTION` / `DROP PROCEDURE`. Each target arrives as
298/// an `ObjectWithArgs`; the argument type list (when spelled) is
299/// preserved as a typed signature because routine identity includes
300/// `(schema, name, argument types)`.
301pub fn plan_only_for_test(sql: &str) -> Result<Vec<Statement>> {
302    compile(sql)
303}
uqa_sql/compiler/dispatch.rs

uqa_sql/compiler/
dispatch.rs
