Add option to pick Linux/BSD backends

This commit adds two cargo features `x11` and `wayland` to pick
Linux/BSD backends, with both enabled by default.

Fixes #3340.

5 files changed, 41 insertions, 17 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a21b5803..9e241586 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Packaging
 
 - Minimum Rust version has been bumped to 1.37.0
+- Added Rust features `x11` and `wayland` to pick backends, with both enabled by default
 
 ### Changed
 
diff --git a/alacritty/Cargo.toml b/alacritty/Cargo.toml
index b68d10e0..05574363 100644
--- a/alacritty/Cargo.toml
+++ b/alacritty/Cargo.toml
@@ -9,7 +9,7 @@ homepage = "https://github.com/alacritty/alacritty"
 edition = "2018"
 
 [dependencies]
-alacritty_terminal = { path = "../alacritty_terminal" }
+alacritty_terminal = { path = "../alacritty_terminal", default-features = false }
 clap = "2"
 log = "0.4"
 time = "0.1.40"
@@ -49,7 +49,9 @@ winapi = { version = "0.3.7", features = ["impl-default", "wincon"]}
 embed-resource = "1.3"
 
 [features]
-default = []
+default = ["wayland", "x11"]
+x11 = ["alacritty_terminal/x11"]
+wayland = ["alacritty_terminal/wayland"]
 # Enabling this feature makes shaders automatically reload when changed
 live-shader-reload = []
 nightly = []
diff --git a/alacritty/build.rs b/alacritty/build.rs
index 16f3a2b3..b2ee8b6e 100644
--- a/alacritty/build.rs
+++ b/alacritty/build.rs
@@ -22,6 +22,10 @@ use std::path::Path;
 use embed_resource;
 
 fn main() {
+    if cfg!(not(any(feature = "x11", feature = "wayland", target_os = "macos", windows))) {
+        panic!("at least one of the \"x11\"/\"wayland\" features must be enabled");
+    }
+
     let hash = rustc_tools_util::get_commit_hash().unwrap_or_default();
     println!("cargo:rustc-env=GIT_HASH={}", hash);
 
diff --git a/alacritty_terminal/Cargo.toml b/alacritty_terminal/Cargo.toml
index f86f9456..2fe46d0d 100644
--- a/alacritty_terminal/Cargo.toml
+++ b/alacritty_terminal/Cargo.toml
@@ -24,7 +24,7 @@ unicode-width = "0.1"
 base64 = "0.11.0"
 terminfo = "0.7.1"
 url = "2"
-copypasta = "0.6.1"
+copypasta = { version = "0.6.3", default-features = false }
 
 [target.'cfg(unix)'.dependencies]
 nix = "0.16.1"
@@ -44,7 +44,9 @@ mio-anonymous-pipes = "0.1"
 objc = "0.2.2"
 
 [features]
-default = []
+default = ["x11", "wayland"]
+x11 = ["copypasta/x11"]
+wayland = ["copypasta/wayland"]
 nightly = []
 bench = []
 
diff --git a/alacritty_terminal/src/clipboard.rs b/alacritty_terminal/src/clipboard.rs
index 6f6a41be..1169cdc3 100644
--- a/alacritty_terminal/src/clipboard.rs
+++ b/alacritty_terminal/src/clipboard.rs
@@ -18,11 +18,13 @@ use std::ffi::c_void;
 use log::{debug, warn};
 
 use copypasta::nop_clipboard::NopClipboardContext;
-#[cfg(not(any(target_os = "macos", target_os = "windows")))]
+#[cfg(all(not(any(target_os = "macos", windows)), feature = "wayland"))]
 use copypasta::wayland_clipboard;
-#[cfg(not(any(target_os = "macos", target_os = "windows")))]
+#[cfg(all(not(any(target_os = "macos", windows)), feature = "x11"))]
 use copypasta::x11_clipboard::{Primary as X11SelectionClipboard, X11ClipboardContext};
-use copypasta::{ClipboardContext, ClipboardProvider};
+#[cfg(any(feature = "x11", target_os = "macos", windows))]
+use copypasta::ClipboardContext;
+use copypasta::ClipboardProvider;
 
 pub struct Clipboard {
     clipboard: Box<dyn ClipboardProvider>,
@@ -30,23 +32,33 @@ pub struct Clipboard {
 }
 
 impl Clipboard {
-    #[cfg(any(target_os = "macos", target_os = "windows"))]
+    #[cfg(any(target_os = "macos", windows))]
     pub fn new() -> Self {
         Self::default()
     }
 
-    #[cfg(not(any(target_os = "macos", target_os = "windows")))]
-    pub fn new(display: Option<*mut c_void>) -> Self {
-        if let Some(display) = display {
-            let (selection, clipboard) =
-                unsafe { wayland_clipboard::create_clipboards_from_external(display) };
-            return Self { clipboard: Box::new(clipboard), selection: Some(Box::new(selection)) };
+    #[cfg(not(any(target_os = "macos", windows)))]
+    pub fn new(_display: Option<*mut c_void>) -> Self {
+        #[cfg(feature = "wayland")]
+        {
+            if let Some(display) = _display {
+                let (selection, clipboard) =
+                    unsafe { wayland_clipboard::create_clipboards_from_external(display) };
+                return Self {
+                    clipboard: Box::new(clipboard),
+                    selection: Some(Box::new(selection)),
+                };
+            }
         }
 
-        Self {
+        #[cfg(feature = "x11")]
+        return Self {
             clipboard: Box::new(ClipboardContext::new().unwrap()),
             selection: Some(Box::new(X11ClipboardContext::<X11SelectionClipboard>::new().unwrap())),
-        }
+        };
+
+        #[cfg(not(feature = "x11"))]
+        return Self::new_nop();
     }
 
     // Use for tests and ref-tests
@@ -57,7 +69,10 @@ impl Clipboard {
 
 impl Default for Clipboard {
     fn default() -> Self {
-        Self { clipboard: Box::new(ClipboardContext::new().unwrap()), selection: None }
+        #[cfg(any(feature = "x11", target_os = "macos", windows))]
+        return Self { clipboard: Box::new(ClipboardContext::new().unwrap()), selection: None };
+        #[cfg(not(any(feature = "x11", target_os = "macos", windows)))]
+        return Self::new_nop();
     }
 }