The editor now has context aware completions

pglablib/SqlCompletionProvider.h

@@ -0,0 +1,69 @@
+#ifndef SQLCOMPLETIONPROVIDER_H
+#define SQLCOMPLETIONPROVIDER_H
+
+#include "SqlContext.h"
+#include <QString>
+#include <memory>
+#include <vector>
+
+class PgDatabaseCatalog;
+
+struct CompletionItem {
+	QString display;     // text shown in the list
+	QString detail;      // dimmed extra information, for example the relation a column belongs to
+	QString insertText;  // replaces the typed prefix when accepted
+	CompletionKind kind = CompletionKind::None;
+	bool ambiguous = false; // name occurs in more than one relation in scope
+};
+
+/// Plain snapshot of the parts of the catalog needed for completion, so the provider does not need a database.
+struct CompletionRelation {
+	QString schema;
+	QString name;
+	char kind = 'r'; // pg_class.relkind
+	std::vector<QString> columns; // in column order, without dropped and system columns
+};
+
+struct CompletionFunction {
+	QString schema;
+	QString name;
+	char kind = 'f'; // pg_proc.prokind: f function, a aggregate, w window
+};
+
+struct CompletionForeignKey {
+	QString childSchema, childTable;   // table that has the constraint
+	QString parentSchema, parentTable; // referenced table
+	std::vector<QString> childColumns;
+	std::vector<QString> parentColumns; // same length as childColumns
+};
+
+struct CompletionCatalog {
+	std::vector<QString> schemas;
+	std::vector<CompletionRelation> relations;
+	std::vector<CompletionFunction> functions;
+	std::vector<CompletionForeignKey> foreignKeys;
+	/// Schemas that are searched when a relation is not schema qualified, in order
+	std::vector<QString> searchPath = { QStringLiteral("public"), QStringLiteral("pg_catalog") };
+};
+
+CompletionCatalog buildCompletionCatalog(const PgDatabaseCatalog &catalog);
+
+class SqlCompletionProvider {
+public:
+	SqlCompletionProvider() = default;
+	explicit SqlCompletionProvider(CompletionCatalog catalog);
+
+	std::vector<CompletionItem> complete(const SqlContext &ctx) const;
+
+private:
+	CompletionCatalog m_catalog;
+
+	const CompletionRelation* resolve(const RelationRef &ref) const;
+	std::vector<CompletionItem> relationItems(const SqlContext &ctx, const QString &schema) const;
+	std::vector<CompletionItem> columnItems(const SqlContext &ctx) const;
+	std::vector<CompletionItem> qualifiedColumnItems(const SqlContext &ctx) const;
+	std::vector<CompletionItem> joinItems(const SqlContext &ctx) const;
+	void addFunctionItems(const SqlContext &ctx, std::vector<CompletionItem> &items) const;
+};
+
+#endif // SQLCOMPLETIONPROVIDER_H