rb_ext_resolve_symbol: C API to resolve and return externed symbols [Feature #20005]

This is a C API for extensions to resolve and get function symbols of other extensions.
Extensions can check the expected symbol is correctly loaded and accessible, and
use it if it is available.
Otherwise, extensions can raise their own error to guide users to setup their
environments correctly and what's missing.

12 files changed, 129 insertions, 0 deletions

diff --git a/ext/-test-/load/resolve_symbol_resolver/extconf.rb b/ext/-test-/load/resolve_symbol_resolver/extconf.rb
new file mode 100644
index 0000000000..2299efcfd3
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_resolver/extconf.rb
@@ -0,0 +1 @@
+create_makefile('-test-/load/resolve_symbol_resolver')
diff --git a/ext/-test-/load/resolve_symbol_resolver/resolve_symbol_resolver.c b/ext/-test-/load/resolve_symbol_resolver/resolve_symbol_resolver.c
new file mode 100644
index 0000000000..a996e2e26e
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_resolver/resolve_symbol_resolver.c
@@ -0,0 +1,50 @@
+#include <ruby.h>
+#include "ruby/internal/intern/load.h"
+
+typedef VALUE(*target_func)(VALUE);
+
+static target_func rst_any_method;
+
+VALUE
+rsr_any_method(VALUE klass)
+{
+    return rst_any_method((VALUE)NULL);
+}
+
+VALUE
+rsr_try_resolve_fname(VALUE klass)
+{
+    target_func rst_something_missing =
+        (target_func) rb_ext_resolve_symbol("-test-/load/resolve_symbol_missing", "rst_any_method");
+    if (rst_something_missing == NULL) {
+        // This should be done in Init_*, so the error is LoadError
+        rb_raise(rb_eLoadError, "symbol not found: missing fname");
+    }
+    return Qtrue;
+}
+
+VALUE
+rsr_try_resolve_sname(VALUE klass)
+{
+    target_func rst_something_missing =
+        (target_func)rb_ext_resolve_symbol("-test-/load/resolve_symbol_target", "rst_something_missing");
+    if (rst_something_missing == NULL) {
+        // This should be done in Init_*, so the error is LoadError
+        rb_raise(rb_eLoadError, "symbol not found: missing sname");
+    }
+    return Qtrue;
+}
+
+void
+Init_resolve_symbol_resolver(void)
+{
+    VALUE mod = rb_define_module("ResolveSymbolResolver");
+    rb_define_singleton_method(mod, "any_method", rsr_any_method, 0);
+    rb_define_singleton_method(mod, "try_resolve_fname", rsr_try_resolve_fname, 0);
+    rb_define_singleton_method(mod, "try_resolve_sname", rsr_try_resolve_sname, 0);
+
+    rst_any_method = (target_func)rb_ext_resolve_symbol("-test-/load/resolve_symbol_target", "rst_any_method");
+    if (rst_any_method == NULL) {
+        rb_raise(rb_eLoadError, "resolve_symbol_target is not loaded");
+    }
+}
diff --git a/ext/-test-/load/resolve_symbol_target/extconf.rb b/ext/-test-/load/resolve_symbol_target/extconf.rb
new file mode 100644
index 0000000000..b5a99ca7f1
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_target/extconf.rb
@@ -0,0 +1 @@
+create_makefile('-test-/load/resolve_symbol_target')
diff --git a/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.c b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.c
new file mode 100644
index 0000000000..b5bc9e8ee0
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.c
@@ -0,0 +1,15 @@
+#include <ruby.h>
+#include "resolve_symbol_target.h"
+
+VALUE
+rst_any_method(VALUE klass)
+{
+    return rb_str_new_cstr("from target");
+}
+
+void
+Init_resolve_symbol_target(void)
+{
+    VALUE mod = rb_define_module("ResolveSymbolTarget");
+    rb_define_singleton_method(mod, "any_method", rst_any_method, 0);
+}
diff --git a/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.def b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.def
new file mode 100644
index 0000000000..c2ed3610fe
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.def
@@ -0,0 +1,4 @@
+LIBRARY resolve_symbol_target
+EXPORTS
+  Init_resolve_symbol_target
+  rst_any_method
diff --git a/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.h b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.h
new file mode 100644
index 0000000000..7d471bf360
--- /dev/null
+++ b/ext/-test-/load/resolve_symbol_target/resolve_symbol_target.h
@@ -0,0 +1,4 @@
+#include <ruby.h>
+#include "ruby/internal/dllexport.h"
+
+RUBY_EXTERN VALUE rst_any_method(VALUE);
diff --git a/ext/-test-/load/stringify_symbols/extconf.rb b/ext/-test-/load/stringify_symbols/extconf.rb
new file mode 100644
index 0000000000..ac39c15f09
--- /dev/null
+++ b/ext/-test-/load/stringify_symbols/extconf.rb
@@ -0,0 +1 @@
+create_makefile('-test-/load/stringify_symbols')
diff --git a/ext/-test-/load/stringify_symbols/stringify_symbols.c b/ext/-test-/load/stringify_symbols/stringify_symbols.c
new file mode 100644
index 0000000000..11a5ee3bc5
--- /dev/null
+++ b/ext/-test-/load/stringify_symbols/stringify_symbols.c
@@ -0,0 +1,29 @@
+#include <ruby.h>
+#include "ruby/internal/intern/load.h"
+#include "ruby/util.h"
+
+#if SIZEOF_INTPTR_T == SIZEOF_LONG_LONG
+#   define UINTPTR2NUM ULL2NUM
+#elif SIZEOF_INTPTR_T == SIZEOF_LONG
+#   define UINTPTR2NUM ULONG2NUM
+#else
+#   define UINTPTR2NUM UINT2NUM
+#endif
+
+static VALUE
+stringify_symbol(VALUE klass, VALUE fname, VALUE sname)
+{
+    void *ptr = rb_ext_resolve_symbol(StringValueCStr(fname), StringValueCStr(sname));
+    if (ptr == NULL) {
+        return Qnil;
+    }
+    uintptr_t uintptr = (uintptr_t)ptr;
+    return UINTPTR2NUM(uintptr);
+}
+
+void
+Init_stringify_symbols(void)
+{
+    VALUE mod = rb_define_module("StringifySymbols");
+    rb_define_singleton_method(mod, "stringify_symbol", stringify_symbol, 2);
+}
diff --git a/ext/-test-/load/stringify_target/extconf.rb b/ext/-test-/load/stringify_target/extconf.rb
new file mode 100644
index 0000000000..4aa201cb09
--- /dev/null
+++ b/ext/-test-/load/stringify_target/extconf.rb
@@ -0,0 +1 @@
+create_makefile('-test-/load/stringify_target')
diff --git a/ext/-test-/load/stringify_target/stringify_target.c b/ext/-test-/load/stringify_target/stringify_target.c
new file mode 100644
index 0000000000..ce09b8fd77
--- /dev/null
+++ b/ext/-test-/load/stringify_target/stringify_target.c
@@ -0,0 +1,15 @@
+#include <ruby.h>
+#include "stringify_target.h"
+
+VALUE
+stt_any_method(VALUE klass)
+{
+    return rb_str_new_cstr("from target");
+}
+
+void
+Init_stringify_target(void)
+{
+    VALUE mod = rb_define_module("StringifyTarget");
+    rb_define_singleton_method(mod, "any_method", stt_any_method, 0);
+}
diff --git a/ext/-test-/load/stringify_target/stringify_target.def b/ext/-test-/load/stringify_target/stringify_target.def
new file mode 100644
index 0000000000..89c2b762de
--- /dev/null
+++ b/ext/-test-/load/stringify_target/stringify_target.def
@@ -0,0 +1,4 @@
+LIBRARY stringify_target
+EXPORTS
+  Init_stringify_target
+  stt_any_method
diff --git a/ext/-test-/load/stringify_target/stringify_target.h b/ext/-test-/load/stringify_target/stringify_target.h
new file mode 100644
index 0000000000..5081f8cbd6
--- /dev/null
+++ b/ext/-test-/load/stringify_target/stringify_target.h
@@ -0,0 +1,4 @@
+#include <ruby.h>
+#include "ruby/internal/dllexport.h"
+
+RUBY_EXTERN VALUE stt_any_method(VALUE);