quickjs.h: Add JS_MODULE_EXTERN macro and use it in examples/

The new macro is a counterpart to JS_EXTERN, but for binary C modules.
This commit introduces one more preprocessor define that must be set
when building C modules.

This commit changes examples/fib.c and examples/point.c to use the new
macro, while also removing redundant JS_SHARED_LIBRARY. Additionally,
the includes use the angled brackets now since quickjs.h is supposed to
be external to the binary modules.

meson.build is fixed to properly add the include directory; the manual
header copying has also been removed as it is redundant.

Signed-off-by: Zurab Kvachadze <[email protected]>

CMakeLists.txt

@@ -304,6 +304,23 @@ if(QJS_LIB_TYPE STREQUAL "SHARED_LIBRARY")
     )
 endif()
 
+# An interface library for modules.
+add_library(qjs_module_lib INTERFACE)
+target_include_directories(qjs_module_lib INTERFACE
+    $<TARGET_PROPERTY:qjs,INTERFACE_INCLUDE_DIRECTORIES>
+)
+target_compile_definitions(qjs_module_lib INTERFACE
+    QUICKJS_NG_MODULE_BUILD
+    $<TARGET_PROPERTY:qjs,INTERFACE_COMPILE_DEFINITIONS>
+)
+if(WIN32)
+    # Since Windows cannot resolve symbols at load time, we need to
+    # explicitly link it to qjs.
+    target_link_libraries(qjs_module_lib INTERFACE
+        qjs
+    )
+endif()
+
 if(NOT QJS_BUILD_LIBC)
     add_library(qjs-libc STATIC quickjs-libc.c)
     target_compile_definitions(qjs-libc PRIVATE ${qjs_defines})
@@ -442,6 +459,15 @@ target_link_libraries(function_source PRIVATE qjs)
 #
 
 if(QJS_BUILD_EXAMPLES)
+    if(WIN32 AND NOT (QJS_LIB_TYPE STREQUAL "SHARED_LIBRARY"))
+        message(AUTHOR_WARNING
+            "Binary modules used with static qjs on Windows. There might be\n"
+            "runtime errors when the module is used due to two copies of qjs\n"
+            "in memory.\n"
+            "Please use \"-DBUILD_SHARED_LIBS=true\" if possible."
+        )
+    endif()
+
     add_executable(hello
         gen/hello.c
     )
@@ -461,35 +487,30 @@ if(QJS_BUILD_EXAMPLES)
     add_library(fib MODULE examples/fib.c)
     set_target_properties(fib PROPERTIES
         PREFIX ""
-        C_VISIBILITY_PRESET default
     )
-    target_compile_definitions(fib PRIVATE JS_SHARED_LIBRARY)
-    if(WIN32)
-        target_link_libraries(fib PRIVATE qjs)
-    elseif(APPLE)
+    target_link_libraries(fib PRIVATE qjs_module_lib)
+    if(APPLE)
         target_link_options(fib PRIVATE -undefined dynamic_lookup)
     endif()
 
     add_library(point MODULE examples/point.c)
     set_target_properties(point PROPERTIES
         PREFIX ""
-        C_VISIBILITY_PRESET default
     )
-    target_compile_definitions(point PRIVATE JS_SHARED_LIBRARY)
-    if(WIN32)
-        target_link_libraries(point PRIVATE qjs)
-    elseif(APPLE)
+    target_link_libraries(point PRIVATE qjs_module_lib)
+    if(APPLE)
         target_link_options(point PRIVATE -undefined dynamic_lookup)
     endif()
 
     add_executable(test_fib
-        examples/fib.c
         gen/test_fib.c
     )
     add_qjs_libc_if_needed(test_fib)
     target_include_directories(test_fib PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
     target_compile_definitions(test_fib PRIVATE ${qjs_defines})
     target_link_libraries(test_fib PRIVATE qjs)
+    # Loads fib.so which depends on symbols from libqjs.
+    set_target_properties(test_fib PROPERTIES ENABLE_EXPORTS TRUE)
 endif()
 
 # Install target

examples/fib.c

@@ -21,7 +21,8 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#include "../quickjs.h"
+
+#include <quickjs.h>
 
 #define countof(x) (sizeof(x) / sizeof((x)[0]))
 
@@ -55,21 +56,7 @@ static int js_fib_init(JSContext *ctx, JSModuleDef *m)
                                   countof(js_fib_funcs));
 }
 
-#ifdef JS_SHARED_LIBRARY
-#define JS_INIT_MODULE js_init_module
-#else
-#define JS_INIT_MODULE js_init_module_fib
-#endif
-
-#ifndef JS_EXTERN
-#ifdef _WIN32
-#define JS_EXTERN __declspec(dllexport)
-#else
-#define JS_EXTERN
-#endif
-#endif
-
-JS_EXTERN JSModuleDef *JS_INIT_MODULE(JSContext *ctx, const char *module_name)
+JS_MODULE_EXTERN JSModuleDef *js_init_module(JSContext *ctx, const char *module_name)
 {
     JSModuleDef *m;
     m = JS_NewCModule(ctx, module_name, js_fib_init);

examples/meson.build

@@ -3,9 +3,8 @@ shared_module(
   'fib.c',
 
   name_prefix: '',
-  gnu_symbol_visibility: 'default',
-  c_args: ['-DJS_SHARED_LIBRARY'],
-  dependencies: host_system == 'windows' ? qjs_dep : [],
+  gnu_symbol_visibility: 'hidden',
+  dependencies: qjs_module_dep,
 )
 
 shared_module(
@@ -13,7 +12,6 @@ shared_module(
   'point.c',
 
   name_prefix: '',
-  gnu_symbol_visibility: 'default',
-  c_args: ['-DJS_SHARED_LIBRARY'],
-  dependencies: host_system == 'windows' ? qjs_dep : [],
+  gnu_symbol_visibility: 'hidden',
+  dependencies: qjs_module_dep,
 )

examples/point.c

@@ -21,9 +21,11 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#include "../quickjs.h"
+
 #include <math.h>
 
+#include <quickjs.h>
+
 #define countof(x) (sizeof(x) / sizeof((x)[0]))
 
 /* Point Class */
@@ -141,15 +143,7 @@ static int js_point_init(JSContext *ctx, JSModuleDef *m)
     return 0;
 }
 
-#ifndef JS_EXTERN
-#ifdef _WIN32
-#define JS_EXTERN __declspec(dllexport)
-#else
-#define JS_EXTERN
-#endif
-#endif
-
-JS_EXTERN JSModuleDef *js_init_module(JSContext *ctx, const char *module_name)
+JS_MODULE_EXTERN JSModuleDef *js_init_module(JSContext *ctx, const char *module_name)
 {
     JSModuleDef *m;
     m = JS_NewCModule(ctx, module_name, js_point_init);

meson.build

@@ -181,13 +181,6 @@ qjs_lib = library(
   qjs_srcs,
   qjs_libc ? qjs_libc_srcs : [],
 
-  # export public headers
-  generator(
-    find_program('cp', 'xcopy'),
-    output: ['@PLAINNAME@'],
-    arguments: ['@INPUT@', '@OUTPUT@'],
-  ).process(qjs_hdrs),
-
   dependencies: qjs_sys_deps,
   link_with: cutils_lib,
   c_args: qjs_c_args,
@@ -214,10 +207,23 @@ qjs_dep = declare_dependency(
   compile_args: qjs_dep_args,
   link_with: qjs_lib,
   dependencies: qjs_sys_deps,
-  include_directories: qjs_lib.private_dir_include(),
+  include_directories: include_directories('.'),
   variables: qjs_export_variables,
 )
 
+if host_system != 'windows'
+  qjs_module_dep = declare_dependency(
+    compile_args: [qjs_dep_args, '-DQUICKJS_NG_MODULE_BUILD'],
+    include_directories: include_directories('.'),
+  )
+else
+  qjs_module_dep = declare_dependency(
+    compile_args: [qjs_dep_args, '-DQUICKJS_NG_MODULE_BUILD'],
+    include_directories: include_directories('.'),
+    # Windows can't resolve symbols at runtime thus we explicitly link to qjs.
+    dependencies: qjs_dep,
+  )
+endif
 
 if qjs_libc
   qjs_libc_dep = declare_dependency(
@@ -643,6 +649,14 @@ alias_target('codegen',
 )
 
 if examples.allowed()
+  if host_system == 'windows' and get_option('default_library') != 'shared'
+    warning('Binary modules used with static qjs on Windows.')
+    warning(
+      'There might be runtime errors when the modules are used due to',
+      'two copies of qjs in memory.'
+    )
+    warning('Please use "-Ddefault_library=shared" if possible.')
+  endif
   executable(
     'hello',
     'gen/hello.c',
@@ -663,7 +677,6 @@ if examples.allowed()
 
   executable(
     'test_fib',
-    'examples/fib.c',
     'gen/test_fib.c',
 
     c_args: qjs_c_args,

quickjs.h

@@ -111,6 +111,28 @@ extern "C" {
 # define JS_LIBC_EXTERN JS_EXTERN
 #endif
 
+/*
+ * `JS_MODULE_EXTERN` -- helper macro that must be used to mark `js_init_module`
+ * and other public functions of the binary modules. See examples/ for examples
+ * of the usage.
+ *
+ * Windows note: -DQUICKJS_NG_MODULE_BUILD must be set when building a binary
+ * module to properly set __declspec.
+ */
+#ifdef QUICKJS_NG_PLAT_WIN32
+# ifdef QUICKJS_NG_MODULE_BUILD
+#  define JS_MODULE_EXTERN __declspec(dllexport)
+# else
+#  define JS_MODULE_EXTERN __declspec(dllimport)
+# endif
+#else
+# ifdef QUICKJS_NG_CC_GNULIKE
+#  define JS_MODULE_EXTERN __attribute__((visibility("default")))
+# else
+#  define JS_MODULE_EXTERN /* nothing */
+# endif
+#endif /* QUICKJS_NG_PLAT_WIN32 */
+
 /* Borrowed from Folly */
 #ifndef JS_PRINTF_FORMAT
 #ifdef _MSC_VER