Add support for C++ modules

CMakeLists.txt

@@ -153,6 +153,20 @@ set(SQLITECPP_INC
 )
 source_group(include FILES ${SQLITECPP_INC})
 
+# modules
+option(SQLITECPP_BUILD_MODULES "Build C++ modules support" OFF)
+
+if(SQLITECPP_BUILD_MODULES)
+    if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.28)
+        message(STATUS "Building SQLiteCpp C++ modules (CMake ${CMAKE_VERSION} supports modules)")
+        add_subdirectory(src/modules)
+    else()
+        message(WARNING "Skipping SQLiteCpp C++ modules (requires CMake 3.28+, found ${CMAKE_VERSION})")
+    endif()
+else()
+    message(STATUS "SQLiteCpp C++ modules support is disabled. Enable with -DSQLITECPP_BUILD_MODULES=ON")
+endif()
+
 # list of test files of the library
 set(SQLITECPP_TESTS
  tests/Column_test.cpp

README.md

@@ -192,6 +192,8 @@ cmake --build .
 ctest --output-on-failure
 ```
 
+To enable building with C++20 modules (and importing the library with `import sqlite;`), pass `SQLITECPP_BUILD_MODULES` to the build system.
+
 #### Building with meson
 
 You can build SQLiteCpp with [meson](https://mesonbuild.com/) using the provided meson project.

docs/README.md

@@ -193,6 +193,8 @@ cmake --build .
 ctest --output-on-failure
 ```
 
+To enable building with C++20 modules (and importing the library with `import sqlite;`), pass `SQLITECPP_BUILD_MODULES` to the build system.
+
 #### CMake options
 
   * For more options on customizing the build, see the [CMakeLists.txt](https://github.com/SRombauts/SQLiteCpp/blob/master/CMakeLists.txt) file.

src/modules/CMakeLists.txt

@@ -0,0 +1,30 @@
+file(GLOB_RECURSE SQLITECPP_MODULES *.cppm)
+
+add_library(sqlitecpp_modules)
+
+cmake_minimum_required(VERSION 3.28)
+
+if(NOT COMMAND configure_cpp_module_target)
+  function(configure_cpp_module_target target)
+    if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.28)
+      target_sources(${target} PUBLIC FILE_SET CXX_MODULES FILES ${SQLITECPP_MODULES})
+    else()
+      message(WARNING "C++ modules require CMake 3.28+. Using standard compilation.")
+      target_sources(${target} PRIVATE ${SQLITECPP_MODULES})
+    endif()
+  endfunction()
+endif()
+
+configure_cpp_module_target(sqlitecpp_modules)
+
+target_link_libraries(sqlitecpp_modules
+  PUBLIC
+    sqlitecpp
+)
+
+target_include_directories(sqlitecpp_modules
+  PRIVATE
+    ${PROJECT_SOURCE_DIR}/include
+)
+
+target_compile_features(sqlitecpp_modules PUBLIC cxx_std_20)

src/modules/Column.cppm

@@ -0,0 +1,30 @@
+/**
+ * @file Column.cppm
+ * @brief Module file for SQLiteCpp Column class.
+ */
+
+module;
+
+#include <SQLiteCpp/Column.h>
+
+export module sqlite.column;
+
+import sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using SQLite::INTEGER;
+    using SQLite::FLOAT;
+    using SQLite::TEXT;
+    using SQLite::BLOB;
+    using SQLite::Null;
+
+    using SQLite::Column;
+
+    using SQLite::operator<<;
+}
+
+export namespace sqlite = SQLite;

src/modules/Database.cppm

@@ -0,0 +1,40 @@
+/**
+ * @file Exception.cppm
+ * @brief Module file for SQLiteCpp Exception class.
+ */
+
+module;
+
+#include <SQLiteCpp/Database.h>
+
+export module sqlite.database;
+
+import sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using SQLite::OPEN_READONLY;
+    using SQLite::OPEN_READWRITE;
+    using SQLite::OPEN_CREATE;
+    using SQLite::OPEN_URI;
+    using SQLite::OPEN_MEMORY;
+    using SQLite::OPEN_NOMUTEX;
+    using SQLite::OPEN_FULLMUTEX;
+    using SQLite::OPEN_SHAREDCACHE;
+    using SQLite::OPEN_PRIVATECACHE;
+    using SQLite::OPEN_NOFOLLOW;
+    using SQLite::OK;
+    using SQLite::VERSION;
+    using SQLite::VERSION_NUMBER;
+
+    using SQLite::getLibVersion;
+    using SQLite::getLibVersionNumber;
+
+    using SQLite::Header;
+    using SQLite::Database;
+}
+
+export namespace sqlite = SQLite;

src/modules/Exception.cppm

@@ -0,0 +1,22 @@
+/**
+ * @file Exception.cppm
+ * @brief Module file for SQLiteCpp Exception class.
+ */
+
+module;
+
+#include <SQLiteCpp/Exception.h>
+
+export module sqlite.exception;
+
+import sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using SQLite::Exception;
+}
+
+export namespace sqlite = SQLite;

src/modules/SQLiteCpp.cppm

@@ -0,0 +1,12 @@
+/**
+ * @file SQLiteCpp.cppm
+ * @brief File containing the module declaration for SQLiteC++.
+ */
+
+export module sqlite;
+
+export import sqlite.column;
+export import sqlite.database;
+export import sqlite.exception;
+export import sqlite.statement;
+export import sqlite.transaction;

src/modules/Statement.cppm

@@ -0,0 +1,25 @@
+/**
+ * @file Statement.cppm
+ * @brief Module file for SQLiteCpp Statement class.
+ */
+
+module;
+
+#include <SQLiteCpp/Statement.h>
+
+export module sqlite.statement;
+
+export import sqlite.column;
+export import sqlite.database;
+
+import sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using SQLite::Statement;
+}
+
+export namespace sqlite = SQLite;

src/modules/Transaction.cppm

@@ -0,0 +1,25 @@
+/**
+ * @file Transaction.cppm
+ * @brief Module file for SQLiteCpp Transaction class.
+ */
+
+module;
+
+#include <SQLiteCpp/Transaction.h>
+
+export module sqlite.transaction;
+
+export import sqlite.database;
+
+import sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using SQLite::TransactionBehavior;
+    using SQLite::Transaction;
+}
+
+export namespace sqlite = SQLite;

src/modules/sqlite3forward.cppm

@@ -0,0 +1,35 @@
+/**
+ * @file sqlite3forward.cppm
+ * @brief Module file containing forward declarations of sqlite3 structs.
+ */
+
+module;
+
+#include <sqlite3.h>
+
+export module sqlite.sqlite3forward;
+
+/**
+ * @namespace SQLite
+ * @brief The SQLite SQLite:: namespace
+ */
+export namespace SQLite {
+    using ::sqlite3;
+    using ::sqlite3_context;
+    using ::sqlite3_stmt;
+    using ::sqlite3_value;
+
+    using ::sqlite3_open;
+    using ::sqlite3_close;
+    using ::sqlite3_prepare_v2;
+    using ::sqlite3_step;
+    using ::sqlite3_finalize;
+    using ::sqlite3_bind_text;
+    using ::sqlite3_bind_int;
+    using ::sqlite3_bind_double;
+    using ::sqlite3_column_text;
+    using ::sqlite3_column_int;
+    using ::sqlite3_column_double;
+    using ::sqlite3_errmsg;
+    using ::sqlite3_errcode;
+}