Use cbindgen

If we're going to scale out our oxidation, let's follow
the path of Firefox (and other projects) further and use
cbindgen: https://github.com/eqrion/cbindgen

It's actually nice that `cbindgen` is packaged today in Fedora,
but I doubt it is elsewhere; we may end up needing to push
that forward, or just vendor it via a `build.rs` script and Cargo.

I chose to rename things to `ROR`/`ror_` since it's shorter.  I
am tempted a bit to rename our internal functions to just `ro_` to
or so.

Closes: #1516
Approved by: jlebon

Makefile-rpm-ostree.am

@@ -95,8 +95,13 @@ $(librpmostree_rust_path): Makefile $(LIBRPMOSTREE_RUST_SRCS)
 	  $(cargo) build --verbose $${frozen} $(CARGO_RELEASE_ARGS)
 EXTRA_DIST += $(LIBRPMOSTREE_RUST_SRCS) rust/Cargo.lock
 
-rpm_ostree_CFLAGS += -Irust/include $(PKGDEP_RPMOSTREE_RS_CFLAGS)
-rpm_ostree_SOURCES += rust/include/librpmostree-rust.h
+# See rust/build.rs - it uses cbindgen as part of the Rust build
+rpmostree-rust.h: $(librpmostree_rust_path)
+	$(AM_V_GEN) src=$$(find @abs_top_builddir@/target/@RUST_TARGET_SUBDIR@/ -name 'rpmostree-rust.h') && \
+	  test -n "$${src}" && ln -sfr "$${src}" rpmostree-rust.h
+BUILT_SOURCES += rpmostree-rust.h
+
+rpm_ostree_CFLAGS += $(PKGDEP_RPMOSTREE_RS_CFLAGS)
 rpm_ostree_LDADD += $(librpmostree_rust_path) $(PKGDEP_RPMOSTREE_RS_LIBS)
 rustfmt:
 	rustfmt $(LIBRPMOSTREE_RUST_SRCS)

rust/Cargo.toml

@@ -2,6 +2,7 @@
 name = "rpmostree-rust"
 version = "0.1.0"
 authors = ["Colin Walters <walters@verbum.org>"]
+build = "build.rs"
 
 [dependencies]
 serde = "1.0"
@@ -16,6 +17,9 @@ tempfile = "3.0.3"
 openat = "0.1.15"
 curl = "0.4.14"
 
+[build-dependencies]
+cbindgen = "0.6.3"
+
 [lib]
 name = "rpmostree_rust"
 path = "src/lib.rs"

rust/build.rs

@@ -0,0 +1,24 @@
+// See https://bugzilla.redhat.com/show_bug.cgi?id=1608670#c3
+// and https://github.com/projectatomic/rpm-ostree/pull/1516
+
+extern crate cbindgen;
+
+fn run() -> Result<(), String> {
+    let out_dir_v = std::env::var("OUT_DIR").expect("OUT_DIR is unset");
+    let out_dir = std::path::Path::new(&out_dir_v);
+    let bindings = cbindgen::generate(std::path::Path::new(".")).map_err(|e| e.to_string())?;
+    // This uses unwraps internally; it'd be good to submit a patch
+    // to add a Result-based API.
+    bindings.write_to_file(out_dir.join("rpmostree-rust.h"));
+    Ok(())
+}
+
+fn main() {
+    match run() {
+        Ok(_) => {}
+        Err(e) => {
+            eprintln!("error: {}", e);
+            std::process::exit(1)
+        }
+    }
+}

rust/cbindgen.toml

@@ -0,0 +1,6 @@
+autogen_warning = "/* Warning, this file is autogenerated by cbindgen. Don't modify this manually. */"
+language = "C"
+header = "#include <gio/gio.h>\ntypedef GError RORGError;"
+
+[export]
+prefix = "ROR"

rust/src/lib.rs

@@ -69,7 +69,7 @@ fn dir_from_dfd(fd: libc::c_int) -> io::Result<openat::Dir> {
 }
 
 #[no_mangle]
-pub extern "C" fn rpmostree_rs_treefile_new(
+pub extern "C" fn ror_treefile_new(
     filename: *const libc::c_char,
     arch: *const libc::c_char,
     workdir_dfd: libc::c_int,
@@ -94,7 +94,7 @@ pub extern "C" fn rpmostree_rs_treefile_new(
 }
 
 #[no_mangle]
-pub extern "C" fn rpmostree_rs_treefile_to_json(
+pub extern "C" fn ror_treefile_to_json(
     tf: *mut Treefile,
     gerror: *mut *mut glib_sys::GError,
 ) -> libc::c_int {
@@ -110,7 +110,7 @@ pub extern "C" fn rpmostree_rs_treefile_to_json(
 }
 
 #[no_mangle]
-pub extern "C" fn rpmostree_rs_treefile_get_rojig_spec_path(
+pub extern "C" fn ror_treefile_get_rojig_spec_path(
     tf: *mut Treefile,
 ) -> *const libc::c_char {
     assert!(!tf.is_null());
@@ -123,7 +123,7 @@ pub extern "C" fn rpmostree_rs_treefile_get_rojig_spec_path(
 }
 
 #[no_mangle]
-pub extern "C" fn rpmostree_rs_treefile_free(tf: *mut Treefile) {
+pub extern "C" fn ror_treefile_free(tf: *mut Treefile) {
     if tf.is_null() {
         return;
     }
@@ -133,7 +133,7 @@ pub extern "C" fn rpmostree_rs_treefile_free(tf: *mut Treefile) {
 }
 
 #[no_mangle]
-pub extern "C" fn rpmostree_rs_download_to_fd(
+pub extern "C" fn ror_download_to_fd(
     url: *const libc::c_char,
     gerror: *mut *mut glib_sys::GError,
 ) -> libc::c_int {

src/app/rpmostree-compose-builtin-tree.c

@@ -125,7 +125,7 @@ typedef struct {
   gboolean rojig_spec_in_workdir;
   char *previous_checksum;
 
-  RpmOstreeRsTreefile *treefile_rs;
+  RORTreefile *treefile_rs;
   JsonParser *treefile_parser;
   JsonNode *treefile_rootval; /* Unowned */
   JsonObject *treefile; /* Unowned */
@@ -156,7 +156,7 @@ rpm_ostree_tree_compose_context_free (RpmOstreeTreeComposeContext *ctx)
   g_free (ctx->ref);
   g_free (ctx->rojig_spec);
   g_free (ctx->previous_checksum);
-  g_clear_pointer (&ctx->treefile_rs, (GDestroyNotify) rpmostree_rs_treefile_free);
+  g_clear_pointer (&ctx->treefile_rs, (GDestroyNotify) ror_treefile_free);
   g_clear_object (&ctx->treefile_parser);
   g_clear_pointer (&ctx->serialized_treefile, (GDestroyNotify)g_bytes_unref);
   g_free (ctx);
@@ -702,13 +702,13 @@ parse_treefile_to_json (RpmOstreeTreeComposeContext  *self,
       g_str_has_suffix (treefile_path, ".yml"))
     {
       const char *arch = self ? dnf_context_get_base_arch (rpmostree_context_get_dnf (self->corectx)) : NULL;
-      self->treefile_rs = rpmostree_rs_treefile_new (treefile_path, arch,
+      self->treefile_rs = ror_treefile_new (treefile_path, arch,
                                                      self->workdir_tmp.fd,
                                                      error);
       if (!self->treefile_rs)
         return glnx_prefix_error (error, "Failed to load YAML treefile");
 
-      glnx_fd_close int json_fd = rpmostree_rs_treefile_to_json (self->treefile_rs, error);
+      glnx_fd_close int json_fd = ror_treefile_to_json (self->treefile_rs, error);
       if (json_fd < 0)
         return FALSE;
       g_autoptr(GInputStream) json_s = g_unix_input_stream_new (json_fd, FALSE);
@@ -1007,7 +1007,7 @@ rpm_ostree_compose_context_new (const char    *treefile_pathstr,
     self->rojig_spec = g_build_filename (gs_file_get_path_cached (treefile_dir), rojig_spec, NULL);
   else if (self->treefile_rs)
     {
-      self->rojig_spec = g_strdup (rpmostree_rs_treefile_get_rojig_spec_path (self->treefile_rs));
+      self->rojig_spec = g_strdup (ror_treefile_get_rojig_spec_path (self->treefile_rs));
       self->rojig_spec_in_workdir = TRUE;
     }
 

src/app/rpmostree-dbus-helpers.c

@@ -1047,7 +1047,7 @@ rpmostree_sort_pkgs_strv (const char *const* pkgs,
           g_str_has_prefix (*pkg, "https://"))
         {
           g_print ("Downloading '%s'... ", *pkg);
-          glnx_autofd int fd = rpmostree_rs_download_to_fd (*pkg, error);
+          glnx_autofd int fd = ror_download_to_fd (*pkg, error);
           if (fd < 0)
             {
               g_print ("failed!\n");