The editor now has context aware completions

core/SqlContext.h

@@ -0,0 +1,70 @@
+#ifndef SQLCONTEXT_H
+#define SQLCONTEXT_H
+
+#include <QString>
+#include <vector>
+
+/**
+ * Kind of names that are expected at the cursor position.
+ */
+enum class CompletionKind {
+	None,
+	Relation,        // schema, table or view name
+	Column,          // column name of the relations in scope
+	QualifiedColumn, // column after "alias." or "table."
+	Schema,
+	Function,
+	JoinTarget       // complete "table alias ON ..." proposal after JOIN
+};
+
+/**
+ * Part of the statement the cursor is in.
+ */
+enum class SqlClause {
+	None,
+	Select,
+	From,
+	Join,
+	On,
+	Where,
+	GroupBy,
+	OrderBy,
+	Having,
+	Set,
+	Update,
+	InsertInto,
+	Returning,
+	Values
+};
+
+/**
+ * An item of a FROM clause (or UPDATE/INSERT target, CTE, derived table).
+ * Names are normalised: unquoted identifiers are folded to lower case.
+ */
+struct RelationRef {
+	QString schema;
+	QString name;  // may be a CTE name or the alias of a derived table
+	QString alias;
+	bool quoted = false; // name was written as quoted identifier
+	bool derived = false; // CTE or sub query, columns are not in the catalog
+};
+
+struct SqlContext {
+	CompletionKind kind = CompletionKind::None;
+	SqlClause clause = SqlClause::None;
+	QString prefix;                // identifier text typed so far (without opening quote)
+	int prefixStart = 0;           // replace range in document
+	int prefixLen = 0;
+	QString qualifier;             // text before '.', if any
+	QString qualifierSchema;       // for schema.table.
+	std::vector<RelationRef> relations; // relations in scope, innermost query first
+	bool prefixWasQuoted = false;
+};
+
+/**
+ * Tolerant analysis of possibly incomplete SQL around the cursor.
+ * @param cursorPos position in text (between characters) where completion is requested.
+ */
+SqlContext analyzeSqlContext(const QString &text, int cursorPos);
+
+#endif // SQLCONTEXT_H