1 files changed, 80 insertions, 21 deletions

diff --git a/platform/default/sqlite3.hpp b/platform/default/sqlite3.hpp
index 82e3ceff6d..20d09b550c 100644
--- a/platform/default/sqlite3.hpp
+++ b/platform/default/sqlite3.hpp
@@ -19,21 +19,55 @@ enum OpenFlag : int {
     PrivateCache = 0x00040000,
 };
 
-struct Exception : std::runtime_error {
-    enum Code : int {
-        OK = 0,
-        CANTOPEN = 14,
-        NOTADB = 26
-    };
+enum class ResultCode : int {
+    OK = 0,
+    Error = 1,
+    Internal = 2,
+    Perm = 3,
+    Abort = 4,
+    Busy = 5,
+    Locked = 6,
+    NoMem = 7,
+    ReadOnly = 8,
+    Interrupt = 9,
+    IOErr = 10,
+    Corrupt = 11,
+    NotFound = 12,
+    Full = 13,
+    CantOpen = 14,
+    Protocol = 15,
+    Schema = 17,
+    TooBig = 18,
+    Constraint = 19,
+    Mismatch = 20,
+    Misuse = 21,
+    NoLFS = 22,
+    Auth = 23,
+    Range = 25,
+    NotADB = 26
+};
 
-    Exception(int err, const char *msg) : std::runtime_error(msg), code(err) {}
-    Exception(int err, const std::string& msg) : std::runtime_error(msg), code(err) {}
-    const int code = OK;
+class Exception : public std::runtime_error {
+public:
+    Exception(int err, const char* msg)
+        : std::runtime_error(msg), code(static_cast<ResultCode>(err)) {
+    }
+    Exception(ResultCode err, const char* msg)
+        : std::runtime_error(msg), code(err) {
+    }
+    Exception(int err, const std::string& msg)
+        : std::runtime_error(msg), code(static_cast<ResultCode>(err)) {
+    }
+    Exception(ResultCode err, const std::string& msg)
+        : std::runtime_error(msg), code(err) {
+    }
+    const ResultCode code = ResultCode::OK;
 };
 
 class DatabaseImpl;
 class Statement;
 class StatementImpl;
+class Query;
 
 class Database {
 private:
@@ -48,7 +82,6 @@ public:
 
     void setBusyTimeout(std::chrono::milliseconds);
     void exec(const std::string &sql);
-    Statement prepare(const char *query);
 
 private:
     std::unique_ptr<DatabaseImpl> impl;
@@ -56,28 +89,54 @@ private:
     friend class Statement;
 };
 
+// A Statement object represents a prepared statement that can be run repeatedly run with a Query object.
 class Statement {
+public:
+    Statement(Database& db, const char* sql);
+    Statement(const Statement&) = delete;
+    Statement(Statement&&) = delete;
+    Statement& operator=(const Statement&) = delete;
+    Statement& operator=(Statement&&) = delete;
+    ~Statement();
+
+    friend class Query;
+
 private:
-    Statement(const Statement &) = delete;
-    Statement &operator=(const Statement &) = delete;
+    std::unique_ptr<StatementImpl> impl;
+
+#ifndef NDEBUG
+    // This flag stores whether there exists a Query object that uses this prepared statement.
+    // There may only be one Query object at a time. Statement objects must outlive Query objects.
+    // While a Query object exists, a Statement object may not be moved or deleted.
+    bool used = false;
+#endif
+};
 
+// A Query object is used to run a database query with a prepared statement (stored in a Statement
+// object). There may only exist one Query object per Statement object. Query objects are designed
+// to be constructed and destroyed frequently.
+class Query {
 public:
-    Statement(Database *db, const char *sql);
-    Statement(Statement &&);
-    ~Statement();
-    Statement &operator=(Statement &&);
+    Query(Statement&);
+    Query(const Query&) = delete;
+    Query(Query&&) = delete;
+    Query& operator=(const Query&) = delete;
+    Query& operator=(Query&&) = delete;
+    ~Query();
 
-    template <typename T> void bind(int offset, T value);
+    template <typename T>
+    void bind(int offset, T value);
 
     // Text
-    void bind(int offset, const char *, std::size_t length, bool retain = true);
+    void bind(int offset, const char*, std::size_t length, bool retain = true);
     void bind(int offset, const std::string&, bool retain = true);
 
     // Blob
-    void bindBlob(int offset, const void *, std::size_t length, bool retain = true);
+    void bindBlob(int offset, const void*, std::size_t length, bool retain = true);
     void bindBlob(int offset, const std::vector<uint8_t>&, bool retain = true);
 
-    template <typename T> T get(int offset);
+    template <typename T>
+    T get(int offset);
 
     bool run();
     void reset();
@@ -87,7 +146,7 @@ public:
     uint64_t changes() const;
 
 private:
-    std::unique_ptr<StatementImpl> impl;
+    Statement& stmt;
 };
 
 class Transaction {