From 61143f5d126c2bc0cf8af12857c82ab45f6e2128 Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
Date: Tue, 8 Jun 2021 11:28:01 +0200
Subject: [PATCH] experimental PVLV support

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
 perlmod-test/src/pkg142.rs | 12 ++++++++++++
 perlmod/src/ffi.rs         |  4 ++++
 perlmod/src/glue.c         | 13 +++++++++++++
 perlmod/src/scalar.rs      | 17 +++++++++++++++++
 test.pl                    |  8 ++++++++
 5 files changed, 54 insertions(+)

diff --git a/perlmod-test/src/pkg142.rs b/perlmod-test/src/pkg142.rs
index b45e0cf..6a9b75a 100644
--- a/perlmod-test/src/pkg142.rs
+++ b/perlmod-test/src/pkg142.rs
@@ -10,4 +10,16 @@ mod export {
 
         Ok(a + b)
     }
+
+    #[export]
+    fn test(t: Option<String>) -> Result<(), Error> {
+        println!("test called with {:?}", t);
+        Ok(())
+    }
+
+    #[export]
+    fn teststr(t: Option<&str>) -> Result<(), Error> {
+        println!("teststr called with {:?}", t);
+        Ok(())
+    }
 }
diff --git a/perlmod/src/ffi.rs b/perlmod/src/ffi.rs
index 1703ecd..b37c661 100644
--- a/perlmod/src/ffi.rs
+++ b/perlmod/src/ffi.rs
@@ -107,6 +107,10 @@ extern "C" {
     pub fn RSPL_LEAVE();
 
     pub fn RSPL_sv_reftype(sv: *const SV, ob: libc::c_int) -> *const libc::c_char;
+
+    pub fn RSPL_PVLV() -> u32;
+    pub fn RSPL_LvTARG(sv: *mut SV) -> *mut SV;
+    pub fn RSPL_vivify_defelem(sv: *mut SV);
 }
 
 /// Argument marker for the stack.
diff --git a/perlmod/src/glue.c b/perlmod/src/glue.c
index fcafdd3..63548ca 100644
--- a/perlmod/src/glue.c
+++ b/perlmod/src/glue.c
@@ -301,6 +301,19 @@ extern const char* RSPL_sv_reftype(const SV *const sv, const int ob) {
     return sv_reftype(sv, ob);
 }
 
+// We we don't need to generate the numeric value:
+extern uint32_t RSPL_PVLV() {
+    return SVt_PVLV;
+}
+
+extern SV* RSPL_LvTARG(SV *sv) {
+    return LvTARG(sv);
+}
+
+extern void RSPL_vivify_defelem(SV *sv) {
+    Perl_vivify_defelem(aTHX_ sv);
+}
+
 /*
 These make are convoluted brainfarts:
         SVt_NULL                 undef
diff --git a/perlmod/src/scalar.rs b/perlmod/src/scalar.rs
index 7c92191..fb84f04 100644
--- a/perlmod/src/scalar.rs
+++ b/perlmod/src/scalar.rs
@@ -205,6 +205,10 @@ impl ScalarRef {
                     let ty = ffi::RSPL_svtype(self.sv());
                     if ty == 0 {
                         Type::Scalar(Flags::empty())
+                    } else if ty == ffi::RSPL_PVLV() {
+                        self.get_target()
+                            .map(|s| s.ty())
+                            .unwrap_or(Type::Other(99))
                     } else {
                         Type::Other(ty as u8)
                     }
@@ -213,6 +217,19 @@ impl ScalarRef {
         }
     }
 
+    /// Dereference this PVLV.
+    pub fn get_target(&self) -> Option<Scalar> {
+        let ptr = unsafe {
+            ffi::RSPL_vivify_defelem(self.sv());
+            ffi::RSPL_LvTARG(self.sv())
+        };
+        if ptr.is_null() {
+            None
+        } else {
+            Some(unsafe { Scalar::from_raw_ref(ptr) })
+        }
+    }
+
     /// Dereference this reference.
     pub fn dereference(&self) -> Option<Scalar> {
         let ptr = unsafe { ffi::RSPL_dereference(self.sv()) };
diff --git a/test.pl b/test.pl
index 591a462..ea67f69 100644
--- a/test.pl
+++ b/test.pl
@@ -4,6 +4,7 @@ use v5.28.0;
 
 use lib '.';
 use RSPM::Bless;
+use RSPM::Foo142;
 
 my $v = RSPM::Bless->new("Hello");
 $v->something();
@@ -13,3 +14,10 @@ my @ret = $v->multi_return();
 say "Got: ".scalar(@ret)." values: @ret";
 
 $v->another(54);
+
+my $param = { a => 1 };
+my $s = "Hello You";
+RSPM::Foo142::test(substr($s, 3, 3));
+RSPM::Foo142::teststr(substr($s, 3, 3));
+RSPM::Foo142::test($param->{x});
+RSPM::Foo142::teststr($param->{x});