Implemented dynamic loading of xcb, xlib_xcb and xlib.

.github/workflows/build_test.yml

@@ -36,7 +36,13 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --all-features
+          args: --features all-extensions,xlib_xcb
+
+      - name: Run cargo test (dl)
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --features all-extensions,xlib_xcb_dl
 
       - name: Run cargo doc
         uses: actions-rs/cargo@v1

Cargo.toml

@@ -1,15 +1,21 @@
 [package]
 name = "xcb"
 version = "1.6.0"
-authors = [ "Remi Thebault <[email protected]>" ]
+authors = ["Remi Thebault <[email protected]>"]
 description = "Rust safe bindings for XCB"
 repository = "https://github.com/rust-x-bindings/rust-xcb"
 documentation = "https://docs.rs/xcb/latest/xcb"
 readme = "README.md"
 keywords = ["xcb", "window", "xlib", "x11", "opengl"]
 license = "MIT"
 build = "build/main.rs"
-exclude = [".github", "examples/todo/*", "gen", "xml/upstream", "xml/upstream_normalized"]
+exclude = [
+    ".github",
+    "examples/todo/*",
+    "gen",
+    "xml/upstream",
+    "xml/upstream_normalized",
+]
 autoexamples = false
 edition = "2018"
 
@@ -23,28 +29,67 @@ quick-xml = "0.30.0"
 libc = "0.2.102"
 bitflags = "1.3.2"
 as-raw-xcb-connection = { version = "1.0", optional = true }
+libloading = { version = "0.9.0", optional = true }
 tiny-xlib = { version = "0.2.4", optional = true }
 
 [dependencies.x11]
 version = "2.19.0"
 optional = true
 features = ["xlib"]
 
+[dependencies.x11-dl]
+version = "2.19.0"
+optional = true
+
 [features]
 default = ["libxcb_v1_14"]
 debug_atom_names = []
-xlib_xcb = ["x11/xlib"]
+dl = ["dep:libloading"]
 libxcb_v1_14 = []
-
-composite = [ "xfixes" ]
-damage = [ "xfixes" ]
+xlib_xcb = ["x11/xlib"]
+xlib_xcb_dl = ["dl", "dep:x11-dl"]
+
+all-extensions = [
+    "composite",
+    "damage",
+    "dpms",
+    "dri2",
+    "dri3",
+    "ge",
+    "glx",
+    "present",
+    "randr",
+    "record",
+    "render",
+    "res",
+    "screensaver",
+    "shape",
+    "shm",
+    "sync",
+    "xevie",
+    "xf86dri",
+    "xf86vidmode",
+    "xfixes",
+    "xinerama",
+    "xinput",
+    "xkb",
+    "xprint",
+    "xselinux",
+    "xtest",
+    "xv",
+    "xvmc",
+]
+
+# Extension features
+composite = ["xfixes"]
+damage = ["xfixes"]
 dpms = []
 dri2 = []
 dri3 = []
 ge = []
 glx = []
-present = [ "render", "xfixes", "sync" ]
-randr = [ "render" ]
+present = ["render", "xfixes", "sync"]
+randr = ["render"]
 record = []
 render = []
 res = []
@@ -55,15 +100,16 @@ sync = []
 xevie = []
 xf86dri = []
 xf86vidmode = []
-xfixes = [ "render", "shape" ]
+xfixes = ["render", "shape"]
 xinerama = []
-xinput = [ "xfixes" ]
+xinput = ["xfixes"]
 xkb = []
 xprint = []
 xselinux = []
 xtest = []
-xv = [ "shm" ]
-xvmc = [ "xv" ]
+xv = ["shm"]
+xvmc = ["xv"]
+
 tiny-xlib = ["dep:tiny-xlib"]
 
 [dev-dependencies]
@@ -100,6 +146,10 @@ name = "get_all_windows"
 name = "opengl_window"
 required-features = ["glx", "xlib_xcb", "dri2"]
 
+[[example]]
+name = "opengl_window_dl"
+required-features = ["dri2", "glx", "xlib_xcb_dl"]
+
 [[example]]
 name = "present_special_event"
 required-features = ["present", "randr"]
@@ -146,4 +196,4 @@ required-features = ["xkb"]
 
 [[example]]
 name = "tiny_xlib"
-required-features = ["tiny-xlib", "as-raw-xcb-connection"]
+required-features = ["tiny-xlib", "as-raw-xcb-connection"]

build/cg/mod.rs

@@ -554,6 +554,11 @@ impl CodeGen {
                 out,
                 "pub fn prefetch_extension_data(conn: &base::Connection) {{"
             )?;
+            writeln!(out, "    #[cfg(feature = \"dl\")]")?;
+            writeln!(
+                out,
+                "    base::xcb_get_conn_funcs!(conn, xcb_prefetch_extension_data);"
+            )?;
             writeln!(out, "    unsafe {{")?;
             writeln!(
                 out,
@@ -582,6 +587,11 @@ impl CodeGen {
                 out,
                 "pub fn get_extension_data(conn: &base::Connection) -> std::option::Option<ext::ExtensionData> {{"
             )?;
+            writeln!(out, "    #[cfg(feature = \"dl\")]")?;
+            writeln!(
+                out,
+                "    base::xcb_get_conn_funcs!(conn, xcb_get_extension_data);"
+            )?;
             writeln!(out, "    unsafe {{")?;
             writeln!(
                 out,

build/cg/request.rs

@@ -885,6 +885,10 @@ impl CodeGen {
         } else {
             "xcb_send_request64"
         };
+
+        writeln!(out)?;
+        writeln!(out, "{}#[cfg(feature = \"dl\")]", cg::ind(2))?;
+        writeln!(out, "{}base::xcb_get_conn_funcs!(c, {});", cg::ind(2), func)?;
         writeln!(out)?;
         writeln!(out, "{}{}(", cg::ind(2), func)?;
         writeln!(out, "{}    c.get_raw_conn(),", cg::ind(2))?;