Add ALTREP view support

R/altrep.R

@@ -0,0 +1,3 @@
+is_altrep <- function(x) {
+  .Call(ffi_is_altrep, x)
+}

R/view.R

@@ -0,0 +1,17 @@
+vec_view <- function(x, start, size) {
+  check_number_whole(start)
+  check_number_whole(size)
+  .Call(ffi_vec_view, x, start, size)
+}
+
+view_inspect <- function(x) {
+  invisible(.Call(ffi_view_inspect, x))
+}
+
+view_is_materialized <- function(x) {
+  .Call(ffi_view_is_materialized, x)
+}
+
+view_materialize <- function(x) {
+  .Call(ffi_view_materialize, x)
+}

src/Makevars

@@ -30,6 +30,7 @@ lib-files = \
         rlang/vec.c \
         rlang/vec-chr.c \
         rlang/vec-lgl.c \
+        rlang/view.c \
         rlang/vendor.c \
         rlang/walk.c
 

src/internal/exported.c

@@ -2,6 +2,9 @@
 #include "../internal/utils.h"
 #include "../internal/vec.h"
 
+// From rlang/rlang.c
+void r_init_library_with_dll(DllInfo* dll, const char* package);
+
 // From rlang/vec.c
 void r_vec_poke_n(r_obj* x, r_ssize offset,
                   r_obj* y, r_ssize from, r_ssize n);
@@ -18,6 +21,13 @@
 }
 
 
+// altrep.h
+
+r_obj* ffi_is_altrep(r_obj* x) {
+  return r_lgl(r_is_altrep(x));
+}
+
+
 // cnd.c
 
 r_obj* ffi_cnd_signal(r_obj* cnd) {
@@ -1053,6 +1063,30 @@
 }
 
 
+// view.c
+
+r_obj* ffi_vec_view(r_obj* x, r_obj* ffi_start, r_obj* ffi_size) {
+  const r_ssize start = r_arg_as_ssize(ffi_start, "start") - 1;
+  const r_ssize size = r_arg_as_ssize(ffi_size, "size");
+  return r_vec_view(x, start, size);
+}
+
+r_obj* ffi_view_inspect(r_obj* x) {
+  r_check_view(x);
+  return r_lgl(r_view_inspect(x));
+}
+
+r_obj* ffi_view_is_materialized(r_obj* x) {
+  r_check_view(x);
+  return r_lgl(r_view_is_materialized(x));
+}
+
+r_obj* ffi_view_materialize(r_obj* x) {
+  r_check_view(x);
+  return r_view_materialize(x);
+}
+
+
 // walk.c
 
 static inline

src/internal/init.c

@@ -111,6 +111,7 @@ static const R_CallMethodDef r_callables[] = {
   {"ffi_init_rlang",                   (DL_FUNC) &ffi_init_rlang, 1},
   {"ffi_interp",                       (DL_FUNC) &ffi_interp, 2},
   {"ffi_interrupt",                    (DL_FUNC) &ffi_interrupt, 0},
+  {"ffi_is_altrep",                    (DL_FUNC) &ffi_is_altrep, 1},
   {"ffi_is_atomic",                    (DL_FUNC) &ffi_is_atomic, 2},
   {"ffi_is_call",                      (DL_FUNC) &ffi_is_call, 4},
   {"ffi_is_character",                 (DL_FUNC) &ffi_is_character, 4},
@@ -238,6 +239,10 @@ static const R_CallMethodDef r_callables[] = {
   {"ffi_vec_poke_n",                   (DL_FUNC) &ffi_vec_poke_n, 5},
   {"ffi_vec_poke_range",               (DL_FUNC) &ffi_vec_poke_range, 5},
   {"ffi_vec_resize",                   (DL_FUNC) &ffi_vec_resize, 2},
+  {"ffi_vec_view",                     (DL_FUNC) &ffi_vec_view, 3},
+  {"ffi_view_inspect",                 (DL_FUNC) &ffi_view_inspect, 1},
+  {"ffi_view_is_materialized",         (DL_FUNC) &ffi_view_is_materialized, 1},
+  {"ffi_view_materialize",             (DL_FUNC) &ffi_view_materialize, 1},
   {"ffi_which_operator",               (DL_FUNC) &ffi_which_operator, 1},
   {"ffi_wref_key",                     (DL_FUNC) &ffi_wref_key, 1},
   {"ffi_wref_value",                   (DL_FUNC) &ffi_wref_value, 1},
@@ -321,6 +326,8 @@ void R_init_rlang(DllInfo* dll) {
 
   R_registerRoutines(dll, NULL, r_callables, NULL, externals);
   R_useDynamicSymbols(dll, FALSE);
+
+  r_init_library_with_dll(dll, "rlang");
 }
 
 

src/rlang/altrep.h

@@ -13,5 +13,26 @@
 # define ALTREP(x) false
 #endif
 
+#if R_VERSION >= R_Version(4, 3, 0)
+#define RLANG_R_HAS_ALTLIST 1
+#else
+#define RLANG_R_HAS_ALTLIST 0
+#endif
+
+static inline
+bool r_is_altrep(r_obj* x) {
+  return ALTREP(x);
+}
+
+static inline
+r_obj* r_altrep_data1(r_obj* x) {
+  return R_altrep_data1(x);
+}
+
+static inline
+r_obj* r_altrep_data2(r_obj* x) {
+  return R_altrep_data2(x);
+}
+
 
 #endif

src/rlang/rlang-types.h

@@ -22,6 +22,7 @@
 
 typedef struct SEXPREC r_obj;
 typedef Rcomplex r_complex;
+typedef Rbyte r_byte;
 
 typedef R_xlen_t r_ssize;
 #define R_SSIZE_MAX R_XLEN_T_MAX

src/rlang/rlang.c

@@ -29,6 +29,7 @@
 #include "vec-chr.c"
 #include "vec-lgl.c"
 #include "vendor.c"
+#include "view.c"
 #include "walk.c"
 
 
@@ -120,4 +121,11 @@ r_obj* r_init_library(r_obj* ns) {
   return r_null;
 }
 
+// This *must* be called before making any calls to the functions
+// provided in the library. Call this function from your `R_init_<package>()`
+// function, passing along the `dll` and your package's name.
+void r_init_library_with_dll(DllInfo* dll, const char* package) {
+  r_init_library_view(dll, package);
+}
+
 bool _r_use_local_precious_list = false;

src/rlang/rlang.h

@@ -72,6 +72,7 @@ bool _r_use_local_precious_list;
 #include "vec-chr.h"
 #include "vec-lgl.h"
 #include "vendor.h"
+#include "view.h"
 #include "walk.h"
 
 

src/rlang/vec.h

@@ -21,9 +21,13 @@ r_complex* r_cpl_begin(r_obj* x) {
   return COMPLEX(x);
 }
 static inline
-void* r_raw_begin(r_obj* x) {
+r_byte* r_raw_begin0(r_obj* x) {
   return RAW(x);
 }
+static inline
+void* r_raw_begin(r_obj* x) {
+  return r_raw_begin0(x);
+}
 
 static inline
 const int* r_int_cbegin(r_obj* x) {
@@ -42,8 +46,12 @@ const r_complex* r_cpl_cbegin(r_obj* x) {
   return (const r_complex*) COMPLEX(x);
 }
 static inline
+const r_byte* r_raw_cbegin0(r_obj* x) {
+  return (const r_byte*) RAW(x);
+}
+static inline
 const void* r_raw_cbegin(r_obj* x) {
-  return (const void*) RAW(x);
+  return (const void*) r_raw_cbegin0(x);
 }
 static inline
 r_obj* const * r_chr_cbegin(r_obj* x) {