1 files changed, 238 insertions, 0 deletions
diff --git a/libdino/src/qlite/query_builder.vala b/libdino/src/qlite/query_builder.vala
new file mode 100644
index 00000000..40514fd5
--- /dev/null
+++ b/libdino/src/qlite/query_builder.vala
@@ -0,0 +1,238 @@
+using Sqlite;
+
+namespace Dino.Qlite {
+
+public class QueryBuilder : StatementBuilder {
+    private bool single_result;
+
+    // SELECT [...]
+    private string column_selector = "*";
+    private Column[] columns = {};
+
+    // FROM [...]
+    protected Table? table;
+    protected string? table_name;
+
+    // JOIN [...]
+    private string joins = "";
+
+    // WHERE [...]
+    protected string selection = "1";
+    internal StatementBuilder.AbstractField[] selection_args = {};
+
+    // ORDER BY [...]
+    private OrderingTerm[]? order_by_terms = {};
+
+    // GROUP BY [...]
+    private string? group_by_term;
+
+    // LIMIT [...] OFFSET [...]
+    private int limit_val;
+    private int offset_val;
+
+    internal QueryBuilder(Database db) {
+        base(db);
+    }
+
+    public QueryBuilder select(Column[] columns = {}) {
+        this.columns = columns;
+        if (columns.length != 0) {
+            for (int i = 0; i < columns.length; i++) {
+                if (column_selector == "*") {
+                    column_selector = columns[i].to_string();
+                } else {
+                    column_selector += ", " + columns[i].to_string();
+                }
+            }
+        } else {
+            column_selector = "*";
+        }
+        return this;
+    }
+
+    public QueryBuilder select_string(string column_selector) {
+        this.columns = {};
+        this.column_selector = column_selector;
+        return this;
+    }
+
+    public virtual QueryBuilder from(Table table) {
+        if (this.table_name != null) error("cannot use from() multiple times.");
+        this.table = table;
+        this.table_name = table.name;
+        return this;
+    }
+
+    public virtual QueryBuilder from_name(string table) {
+        this.table_name = table;
+        return this;
+    }
+
+    public QueryBuilder outer_join_with<T>(Table table, Column<T> lhs, Column<T> rhs, string? as = null) {
+        return outer_join_on(table, @"$lhs = $rhs", as);
+    }
+
+    public QueryBuilder outer_join_on(Table table, string on, string? as = null) {
+        if (as == null) as = table.name;
+        joins += @" LEFT OUTER JOIN $(table.name) AS $as ON $on";
+        return this;
+    }
+
+    public QueryBuilder join_with<T>(Table table, Column<T> lhs, Column<T> rhs, string? as = null) {
+        return join_on(table, @"$lhs = $rhs", as);
+    }
+
+    public QueryBuilder join_on(Table table, string on, string? as = null) {
+        if (as == null) as = table.name;
+        joins += @" JOIN $(table.name) AS $as ON $on";
+        return this;
+    }
+
+    internal QueryBuilder join_name(string table_name, string on) {
+        joins += @" JOIN $table_name ON $on";
+        return this;
+    }
+
+    public QueryBuilder where(string selection, string[] selection_args = {}) {
+        this.selection = @"($(this.selection)) AND ($selection)";
+        foreach (string arg in selection_args) {
+            this.selection_args += new StatementBuilder.StringField(arg);
+        }
+        return this;
+    }
+
+    public QueryBuilder with<T>(Column<T> column, string comp, T value) {
+        if ((column.unique || column.primary_key) && comp == "=") single_result = true;
+        selection_args += new Field<T>(column, value);
+        selection = @"($selection) AND $column $comp ?";
+        return this;
+    }
+
+    public QueryBuilder with_null<T>(Column<T> column) {
+        selection = @"($selection) AND $column ISNULL";
+        return this;
+    }
+
+    public QueryBuilder without_null<T>(Column<T> column) {
+        selection = @"($selection) AND $column NOT NULL";
+        return this;
+    }
+
+    public QueryBuilder order_by(Column column, string dir = "ASC") {
+        order_by_terms += new OrderingTerm(column, dir);
+        return this;
+    }
+
+    public QueryBuilder order_by_name(string name, string dir) {
+        order_by_terms += new OrderingTerm.by_name(name, dir);
+        return this;
+    }
+
+    public QueryBuilder group_by(Column[] columns) {
+        foreach(Column col in columns) {
+            if (group_by_term == null) {
+                group_by_term = col.to_string();
+            } else {
+                group_by_term += @", $col";
+            }
+        }
+        return this;
+    }
+
+    public QueryBuilder limit(int limit) {
+        if (this.limit_val != 0 && limit > this.limit_val) error("tried to increase an existing limit");
+        this.limit_val = limit;
+        return this;
+    }
+
+    public QueryBuilder offset(int offset) {
+        if (this.limit_val == 0) error("limit required before offset");
+        this.offset_val = offset;
+        return this;
+    }
+
+    public QueryBuilder single() {
+        this.single_result = true;
+        return limit(1);
+    }
+
+    public int64 count() {
+        this.column_selector = @"COUNT($column_selector) AS count";
+        this.single_result = true;
+        return row().get_integer("count");
+    }
+
+    private Row? row_() {
+        if (!single_result) error("query is not suited to return a single row, but row() was called.");
+        return iterator().get_next();
+    }
+
+    public RowOption row() {
+        return new RowOption(row_());
+    }
+
+    public T get<T>(Column<T> field, T def = null) {
+        return row().get(field, def);
+    }
+
+    internal override Statement prepare() {
+        Statement stmt = db.prepare(@"SELECT $column_selector $(table_name == null ? "" : @"FROM $((!) table_name)") $joins WHERE $selection $(group_by_term == null ? "" : @"GROUP BY $group_by_term") $(OrderingTerm.all_to_string(order_by_terms)) $(limit_val > 0 ? @" LIMIT $limit_val OFFSET $offset_val" : "")");
+        for (int i = 0; i < selection_args.length; i++) {
+            selection_args[i].bind(stmt, i+1);
+        }
+        return stmt;
+    }
+
+    public RowIterator iterator() {
+        return new RowIterator.from_query_builder(db, this);
+    }
+
+    class OrderingTerm {
+        Column? column;
+        string column_name;
+        string dir;
+
+        public OrderingTerm(Column column, string dir) {
+            this.column = column;
+            this.column_name = column.to_string();
+            this.dir = dir;
+        }
+
+        public OrderingTerm.by_name(string column_name, string dir) {
+            this.column_name = column_name;
+            this.dir = dir;
+        }
+
+        public string to_string() {
+            return @"$column_name $dir";
+        }
+
+        public static string all_to_string(OrderingTerm[]? terms) {
+            if (terms == null || terms.length == 0) return "";
+            string res = "ORDER BY "+terms[0].to_string();
+            for (int i = 1; i < terms.length; i++) {
+                res += @", $(terms[i])";
+            }
+            return res;
+        }
+    }
+}
+
+public class MatchQueryBuilder : QueryBuilder {
+    internal MatchQueryBuilder(Database db, Table table) {
+        base(db);
+        if (table.fts_columns == null) error("MATCH query on non FTS table");
+        from(table);
+        join_name(@"_fts_$table_name", @"_fts_$table_name.docid = $table_name.rowid");
+    }
+
+    public MatchQueryBuilder match(Column<string> column, string match) {
+        if (table == null) error("MATCH must occur after FROM statement");
+        if (!(column in table.fts_columns)) error("MATCH selection on non FTS column");
+        selection_args += new StatementBuilder.StringField(match);
+        selection = @"($selection) AND _fts_$table_name.$(column.name) MATCH ?";
+        return this;
+    }
+}
+
+}