scythe_codegen/backends/
csharp_mysqlconnector.rs

1use std::fmt::Write;
2use std::path::Path;
3
4use scythe_backend::manifest::{BackendManifest, load_manifest};
5use scythe_backend::naming::{
6    enum_type_name, enum_variant_name, fn_name, row_struct_name, to_pascal_case,
7};
8use scythe_backend::types::resolve_type;
9
10use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
11use scythe_core::errors::{ErrorCode, ScytheError};
12use scythe_core::parser::QueryCommand;
13
14use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
15
16const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/csharp-mysqlconnector.toml");
17
18pub struct CsharpMysqlConnectorBackend {
19    manifest: BackendManifest,
20}
21
22impl CsharpMysqlConnectorBackend {
23    pub fn new(engine: &str) -> Result<Self, ScytheError> {
24        match engine {
25            "mysql" | "mariadb" => {}
26            _ => {
27                return Err(ScytheError::new(
28                    ErrorCode::InternalError,
29                    format!(
30                        "csharp-mysqlconnector only supports MySQL, got engine '{}'",
31                        engine
32                    ),
33                ));
34            }
35        }
36        let manifest_path = Path::new("backends/csharp-mysqlconnector/manifest.toml");
37        let manifest = if manifest_path.exists() {
38            load_manifest(manifest_path)
39                .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
40        } else {
41            toml::from_str(DEFAULT_MANIFEST_TOML)
42                .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
43        };
44        Ok(Self { manifest })
45    }
46}
47
48/// Map a neutral type to a MySqlDataReader method.
49fn reader_method(neutral_type: &str) -> &'static str {
50    match neutral_type {
51        "bool" => "GetBoolean",
52        "int16" => "GetInt16",
53        "int32" => "GetInt32",
54        "int64" => "GetInt64",
55        "float32" => "GetFloat",
56        "float64" => "GetDouble",
57        "string" | "json" | "inet" | "interval" | "uuid" => "GetString",
58        "decimal" => "GetDecimal",
59        "date" => "GetFieldValue<DateOnly>",
60        "time" | "time_tz" => "GetFieldValue<TimeOnly>",
61        "datetime" => "GetDateTime",
62        "datetime_tz" => "GetFieldValue<DateTimeOffset>",
63        _ => "GetValue",
64    }
65}
66
67/// Rewrite $1, $2, ... to @p1, @p2, ...
68fn rewrite_params(sql: &str) -> String {
69    let mut result = sql.to_string();
70    for i in (1..=99).rev() {
71        let from = format!("${}", i);
72        let to = format!("@p{}", i);
73        result = result.replace(&from, &to);
74    }
75    result
76}
77
78/// Build the expression to read a column from MySqlDataReader.
79fn column_read_expr(col: &ResolvedColumn, ordinal: usize) -> String {
80    if col.neutral_type.starts_with("enum::") {
81        format!(
82            "(Enum.TryParse<{typ}>(reader.GetString({ord}), true, out var enumVal{ord}) ? enumVal{ord} : throw new InvalidOperationException($\"Invalid enum value '{{reader.GetString({ord})}}' for {typ}\"))",
83            typ = col.lang_type,
84            ord = ordinal
85        )
86    } else {
87        let method = reader_method(&col.neutral_type);
88        format!("reader.{}({})", method, ordinal)
89    }
90}
91
92impl CodegenBackend for CsharpMysqlConnectorBackend {
93    fn name(&self) -> &str {
94        "csharp-mysqlconnector"
95    }
96
97    fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
98        &self.manifest
99    }
100
101    fn supported_engines(&self) -> &[&str] {
102        &["mysql"]
103    }
104
105    fn file_header(&self) -> String {
106        "// Auto-generated by scythe. Do not edit.\nusing MySqlConnector;\n\npublic static class Queries {"
107            .to_string()
108    }
109
110    fn file_footer(&self) -> String {
111        "}".to_string()
112    }
113
114    fn generate_row_struct(
115        &self,
116        query_name: &str,
117        columns: &[ResolvedColumn],
118    ) -> Result<String, ScytheError> {
119        let struct_name = row_struct_name(query_name, &self.manifest.naming);
120        let mut out = String::new();
121        let _ = writeln!(out, "public record {}(", struct_name);
122        for (i, c) in columns.iter().enumerate() {
123            let field = to_pascal_case(&c.field_name);
124            let sep = if i + 1 < columns.len() { "," } else { "" };
125            let _ = writeln!(out, "    {} {}{}", c.full_type, field, sep);
126        }
127        let _ = write!(out, ");");
128        Ok(out)
129    }
130
131    fn generate_model_struct(
132        &self,
133        table_name: &str,
134        columns: &[ResolvedColumn],
135    ) -> Result<String, ScytheError> {
136        let name = to_pascal_case(table_name);
137        self.generate_row_struct(&name, columns)
138    }
139
140    fn generate_query_fn(
141        &self,
142        analyzed: &AnalyzedQuery,
143        struct_name: &str,
144        columns: &[ResolvedColumn],
145        params: &[ResolvedParam],
146    ) -> Result<String, ScytheError> {
147        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
148        let sql = rewrite_params(&super::clean_sql_oneline(&analyzed.sql));
149        let mut out = String::new();
150
151        let param_list = params
152            .iter()
153            .map(|p| format!("{} {}", p.full_type, p.field_name))
154            .collect::<Vec<_>>()
155            .join(", ");
156        let sep = if param_list.is_empty() { "" } else { ", " };
157
158        let return_type = match &analyzed.command {
159            QueryCommand::One => format!("{}?", struct_name),
160            QueryCommand::Many | QueryCommand::Batch => {
161                format!("List<{}>", struct_name)
162            }
163            QueryCommand::Exec => "void".to_string(),
164            QueryCommand::ExecResult | QueryCommand::ExecRows => "int".to_string(),
165        };
166
167        let is_async_void = return_type == "void";
168        let task_type = if is_async_void {
169            "Task".to_string()
170        } else {
171            format!("Task<{}>", return_type)
172        };
173
174        let _ = writeln!(
175            out,
176            "public static async {} {}(MySqlConnection conn{}{}) {{",
177            task_type, func_name, sep, param_list
178        );
179
180        let _ = writeln!(
181            out,
182            "    await using var cmd = new MySqlCommand(\"{}\", conn);",
183            sql
184        );
185        for (i, p) in params.iter().enumerate() {
186            let value_expr = if p.neutral_type.starts_with("enum::") {
187                format!("{}.ToString().ToLower()", p.field_name)
188            } else {
189                p.field_name.clone()
190            };
191            let _ = writeln!(
192                out,
193                "    cmd.Parameters.AddWithValue(\"@p{}\", {});",
194                i + 1,
195                value_expr
196            );
197        }
198
199        match &analyzed.command {
200            QueryCommand::One => {
201                let _ = writeln!(
202                    out,
203                    "    await using var reader = await cmd.ExecuteReaderAsync();"
204                );
205                let _ = writeln!(out, "    if (!await reader.ReadAsync()) return null;");
206                let _ = writeln!(out, "    return new {}(", struct_name);
207                for (i, col) in columns.iter().enumerate() {
208                    let expr = column_read_expr(col, i);
209                    let sep = if i + 1 < columns.len() { "," } else { "" };
210                    if col.nullable {
211                        let _ = writeln!(out, "        reader.IsDBNull({i}) ? null : {expr}{sep}");
212                    } else {
213                        let _ = writeln!(out, "        {expr}{sep}");
214                    }
215                }
216                let _ = writeln!(out, "    );");
217            }
218            QueryCommand::Many | QueryCommand::Batch => {
219                let _ = writeln!(
220                    out,
221                    "    await using var reader = await cmd.ExecuteReaderAsync();"
222                );
223                let _ = writeln!(out, "    var results = new List<{}>();", struct_name);
224                let _ = writeln!(out, "    while (await reader.ReadAsync()) {{");
225                let _ = writeln!(out, "        results.Add(new {}(", struct_name);
226                for (i, col) in columns.iter().enumerate() {
227                    let expr = column_read_expr(col, i);
228                    let sep = if i + 1 < columns.len() { "," } else { "" };
229                    if col.nullable {
230                        let _ =
231                            writeln!(out, "            reader.IsDBNull({i}) ? null : {expr}{sep}");
232                    } else {
233                        let _ = writeln!(out, "            {expr}{sep}");
234                    }
235                }
236                let _ = writeln!(out, "        ));");
237                let _ = writeln!(out, "    }}");
238                let _ = writeln!(out, "    return results;");
239            }
240            QueryCommand::Exec => {
241                let _ = writeln!(out, "    await cmd.ExecuteNonQueryAsync();");
242            }
243            QueryCommand::ExecResult | QueryCommand::ExecRows => {
244                let _ = writeln!(out, "    return await cmd.ExecuteNonQueryAsync();");
245            }
246        }
247
248        let _ = write!(out, "}}");
249        Ok(out)
250    }
251
252    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
253        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
254        let mut out = String::new();
255        let _ = writeln!(out, "public enum {} {{", type_name);
256        for value in &enum_info.values {
257            let variant = enum_variant_name(value, &self.manifest.naming);
258            let _ = writeln!(out, "    {},", variant);
259        }
260        let _ = write!(out, "}}");
261        Ok(out)
262    }
263
264    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
265        let name = to_pascal_case(&composite.sql_name);
266        let mut out = String::new();
267        if composite.fields.is_empty() {
268            let _ = writeln!(out, "public record {}();", name);
269        } else {
270            let _ = writeln!(out, "public record {}(", name);
271            for (i, field) in composite.fields.iter().enumerate() {
272                let cs_type = resolve_type(&field.neutral_type, &self.manifest, false)
273                    .map(|t| t.into_owned())
274                    .unwrap_or_else(|_| "object".to_string());
275                let field_name = to_pascal_case(&field.name);
276                let sep = if i + 1 < composite.fields.len() {
277                    ","
278                } else {
279                    ""
280                };
281                let _ = writeln!(out, "    {} {}{}", cs_type, field_name, sep);
282            }
283            let _ = write!(out, ");");
284        }
285        Ok(out)
286    }
287}
scythe_codegen/backends/csharp_mysqlconnector.rs

scythe_codegen/backends/
csharp_mysqlconnector.rs
