mdql_core/
database.rs

1//! Load and validate database-level _mdql.md files (type: database).
2
3use std::path::Path;
4
5use crate::errors::MdqlError;
6use crate::parser::parse_file;
7use crate::schema::MDQL_FILENAME;
8
9#[derive(Debug, Clone)]
10pub struct ForeignKey {
11    pub from_table: String,
12    pub from_column: String,
13    pub to_table: String,
14    pub to_column: String,
15}
16
17#[derive(Debug, Clone)]
18pub struct ViewDef {
19    pub name: String,
20    pub query: String,
21}
22
23#[derive(Debug, Clone)]
24pub struct DatabaseConfig {
25    pub name: String,
26    pub foreign_keys: Vec<ForeignKey>,
27    pub views: Vec<ViewDef>,
28}
29
30pub fn is_database_dir(folder: &Path) -> bool {
31    let mdql_file = folder.join(MDQL_FILENAME);
32    if !mdql_file.exists() {
33        return false;
34    }
35    if let Ok(text) = std::fs::read_to_string(&mdql_file) {
36        if let Some(fm_text) = text
37            .strip_prefix("---\n")
38            .and_then(|rest| rest.split_once("\n---").map(|(fm, _)| fm))
39        {
40            if let Ok(val) = serde_yaml::from_str::<serde_yaml::Value>(fm_text) {
41                if let Some(m) = val.as_mapping() {
42                    return m
43                        .get(&serde_yaml::Value::String("type".into()))
44                        .and_then(|v| v.as_str())
45                        == Some("database");
46                }
47            }
48        }
49    }
50    false
51}
52
53pub fn load_database_config(db_dir: &Path) -> crate::errors::Result<DatabaseConfig> {
54    let db_path = db_dir.join(MDQL_FILENAME);
55    if !db_path.exists() {
56        return Err(MdqlError::DatabaseConfig(format!(
57            "No {} in {}",
58            MDQL_FILENAME,
59            db_dir.display()
60        )));
61    }
62
63    let parsed = parse_file(&db_path, Some(db_dir), false)?;
64
65    if !parsed.parse_errors.is_empty() {
66        return Err(MdqlError::DatabaseConfig(format!(
67            "Cannot parse {}: {}",
68            MDQL_FILENAME,
69            parsed.parse_errors.join("; ")
70        )));
71    }
72
73    let fm = &parsed.raw_frontmatter;
74    let fm_map = fm.as_mapping().ok_or_else(|| {
75        MdqlError::DatabaseConfig(format!(
76            "{}: frontmatter must be a mapping",
77            MDQL_FILENAME
78        ))
79    })?;
80
81    let type_val = fm_map.get(&serde_yaml::Value::String("type".into()));
82    if type_val.and_then(|v| v.as_str()) != Some("database") {
83        return Err(MdqlError::DatabaseConfig(format!(
84            "{}: frontmatter must have 'type: database'",
85            MDQL_FILENAME
86        )));
87    }
88
89    let name = fm_map
90        .get(&serde_yaml::Value::String("name".into()))
91        .and_then(|v| v.as_str())
92        .ok_or_else(|| {
93            MdqlError::DatabaseConfig(format!(
94                "{}: frontmatter must have 'name' as a string",
95                MDQL_FILENAME
96            ))
97        })?
98        .to_string();
99
100    let mut fks = Vec::new();
101    if let Some(fk_list) = fm_map.get(&serde_yaml::Value::String("foreign_keys".into())) {
102        if let Some(seq) = fk_list.as_sequence() {
103            for fk_def in seq {
104                let fk_map = fk_def.as_mapping().ok_or_else(|| {
105                    MdqlError::DatabaseConfig(format!(
106                        "{}: each foreign_key must be a mapping",
107                        MDQL_FILENAME
108                    ))
109                })?;
110
111                let from_spec = fk_map
112                    .get(&serde_yaml::Value::String("from".into()))
113                    .and_then(|v| v.as_str())
114                    .unwrap_or("");
115                let to_spec = fk_map
116                    .get(&serde_yaml::Value::String("to".into()))
117                    .and_then(|v| v.as_str())
118                    .unwrap_or("");
119
120                if !from_spec.contains('.') || !to_spec.contains('.') {
121                    return Err(MdqlError::DatabaseConfig(format!(
122                        "{}: foreign_key 'from' and 'to' must be 'table.column' format",
123                        MDQL_FILENAME
124                    )));
125                }
126
127                let (from_table, from_col) = from_spec.split_once('.').unwrap();
128                let (to_table, to_col) = to_spec.split_once('.').unwrap();
129
130                fks.push(ForeignKey {
131                    from_table: from_table.to_string(),
132                    from_column: from_col.to_string(),
133                    to_table: to_table.to_string(),
134                    to_column: to_col.to_string(),
135                });
136            }
137        }
138    }
139
140    let mut views = Vec::new();
141    if let Some(view_list) = fm_map.get(&serde_yaml::Value::String("views".into())) {
142        if let Some(seq) = view_list.as_sequence() {
143            for view_def in seq {
144                let view_map = view_def.as_mapping().ok_or_else(|| {
145                    MdqlError::DatabaseConfig(format!(
146                        "{}: each view must be a mapping with 'name' and 'query'",
147                        MDQL_FILENAME
148                    ))
149                })?;
150
151                let view_name = view_map
152                    .get(&serde_yaml::Value::String("name".into()))
153                    .and_then(|v| v.as_str())
154                    .ok_or_else(|| {
155                        MdqlError::DatabaseConfig(format!(
156                            "{}: each view must have a 'name' string",
157                            MDQL_FILENAME
158                        ))
159                    })?
160                    .to_string();
161
162                let view_query = view_map
163                    .get(&serde_yaml::Value::String("query".into()))
164                    .and_then(|v| v.as_str())
165                    .ok_or_else(|| {
166                        MdqlError::DatabaseConfig(format!(
167                            "{}: view '{}' must have a 'query' string",
168                            MDQL_FILENAME, view_name
169                        ))
170                    })?
171                    .to_string();
172
173                views.push(ViewDef {
174                    name: view_name,
175                    query: view_query,
176                });
177            }
178        }
179    }
180
181    Ok(DatabaseConfig {
182        name,
183        foreign_keys: fks,
184        views,
185    })
186}
187
188pub fn save_database_config(db_dir: &Path, config: &DatabaseConfig) -> crate::errors::Result<()> {
189    let db_path = db_dir.join(MDQL_FILENAME);
190    let text = std::fs::read_to_string(&db_path)?;
191
192    let (_before_fm, fm_text, after_fm) = if let Some(rest) = text.strip_prefix("---\n") {
193        if let Some((fm, after)) = rest.split_once("\n---") {
194            ("---\n".to_string(), fm.to_string(), format!("\n---{}", after))
195        } else {
196            return Err(MdqlError::DatabaseConfig("Malformed frontmatter".into()));
197        }
198    } else {
199        return Err(MdqlError::DatabaseConfig("No frontmatter found".into()));
200    };
201
202    let mut fm: serde_yaml::Value = serde_yaml::from_str(&fm_text)
203        .map_err(|e| MdqlError::DatabaseConfig(format!("YAML parse error: {}", e)))?;
204
205    let fm_map = fm.as_mapping_mut().ok_or_else(|| {
206        MdqlError::DatabaseConfig("Frontmatter is not a mapping".into())
207    })?;
208
209    let views_key = serde_yaml::Value::String("views".into());
210    if config.views.is_empty() {
211        fm_map.remove(&views_key);
212    } else {
213        let views_seq: Vec<serde_yaml::Value> = config
214            .views
215            .iter()
216            .map(|v| {
217                let mut m = serde_yaml::Mapping::new();
218                m.insert(
219                    serde_yaml::Value::String("name".into()),
220                    serde_yaml::Value::String(v.name.clone()),
221                );
222                m.insert(
223                    serde_yaml::Value::String("query".into()),
224                    serde_yaml::Value::String(v.query.clone()),
225                );
226                serde_yaml::Value::Mapping(m)
227            })
228            .collect();
229        fm_map.insert(views_key, serde_yaml::Value::Sequence(views_seq));
230    }
231
232    let new_fm_text = serde_yaml::to_string(&fm)
233        .map_err(|e| MdqlError::DatabaseConfig(format!("YAML serialize error: {}", e)))?;
234
235    let new_content = format!("---\n{}---{}", new_fm_text, &after_fm[4..]);
236    crate::txn::atomic_write(&db_path, &new_content)?;
237    Ok(())
238}
mdql_core/database.rs

mdql_core/
database.rs
