gpui: Add Global marker trait (#7095)

This should prevent a class of bugs where one queries the wrong type of
global, which results in oddities at runtime.

Release Notes:

- N/A

---------

Co-authored-by: Marshall <marshall@zed.dev>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/release_channel/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "release_channel"
+version = "0.1.0"
+edition = "2021"
+publish = false
+license = "GPL-3.0-or-later"
+
+[dependencies]
+gpui = { path = "../gpui" }
+once_cell = "1.19.0"

crates/release_channel/LICENSE-GPL

@@ -0,0 +1 @@
+../../LICENSE-GPL

crates/release_channel/src/lib.rs

@@ -0,0 +1,130 @@
+use gpui::{AppContext, Global};
+use once_cell::sync::Lazy;
+use std::env;
+
+#[doc(hidden)]
+pub static RELEASE_CHANNEL_NAME: Lazy<String> = if cfg!(debug_assertions) {
+    Lazy::new(|| {
+        env::var("ZED_RELEASE_CHANNEL")
+            .unwrap_or_else(|_| include_str!("../../zed/RELEASE_CHANNEL").to_string())
+    })
+} else {
+    Lazy::new(|| include_str!("../../zed/RELEASE_CHANNEL").to_string())
+};
+#[doc(hidden)]
+pub static RELEASE_CHANNEL: Lazy<ReleaseChannel> =
+    Lazy::new(|| match RELEASE_CHANNEL_NAME.as_str().trim() {
+        "dev" => ReleaseChannel::Dev,
+        "nightly" => ReleaseChannel::Nightly,
+        "preview" => ReleaseChannel::Preview,
+        "stable" => ReleaseChannel::Stable,
+        _ => panic!("invalid release channel {}", *RELEASE_CHANNEL_NAME),
+    });
+
+#[derive(Clone)]
+pub struct AppCommitSha(pub String);
+
+struct GlobalAppCommitSha(AppCommitSha);
+
+impl Global for GlobalAppCommitSha {}
+
+impl AppCommitSha {
+    pub fn try_global(cx: &AppContext) -> Option<AppCommitSha> {
+        cx.try_global::<GlobalAppCommitSha>()
+            .map(|sha| sha.0.clone())
+    }
+
+    pub fn set_global(sha: AppCommitSha, cx: &mut AppContext) {
+        cx.set_global(GlobalAppCommitSha(sha))
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Default)]
+pub enum ReleaseChannel {
+    #[default]
+    Dev,
+    Nightly,
+    Preview,
+    Stable,
+}
+
+struct GlobalReleaseChannel(ReleaseChannel);
+
+impl Global for GlobalReleaseChannel {}
+
+impl ReleaseChannel {
+    pub fn init(cx: &mut AppContext) {
+        cx.set_global(GlobalReleaseChannel(*RELEASE_CHANNEL))
+    }
+
+    pub fn global(cx: &AppContext) -> Self {
+        cx.global::<GlobalReleaseChannel>().0
+    }
+
+    pub fn try_global(cx: &AppContext) -> Option<Self> {
+        cx.try_global::<GlobalReleaseChannel>()
+            .map(|channel| channel.0)
+    }
+
+    pub fn display_name(&self) -> &'static str {
+        match self {
+            ReleaseChannel::Dev => "Zed Dev",
+            ReleaseChannel::Nightly => "Zed Nightly",
+            ReleaseChannel::Preview => "Zed Preview",
+            ReleaseChannel::Stable => "Zed",
+        }
+    }
+
+    pub fn dev_name(&self) -> &'static str {
+        match self {
+            ReleaseChannel::Dev => "dev",
+            ReleaseChannel::Nightly => "nightly",
+            ReleaseChannel::Preview => "preview",
+            ReleaseChannel::Stable => "stable",
+        }
+    }
+
+    pub fn url_scheme(&self) -> &'static str {
+        match self {
+            ReleaseChannel::Dev => "zed-dev://",
+            ReleaseChannel::Nightly => "zed-nightly://",
+            ReleaseChannel::Preview => "zed-preview://",
+            ReleaseChannel::Stable => "zed://",
+        }
+    }
+
+    pub fn link_prefix(&self) -> &'static str {
+        match self {
+            ReleaseChannel::Dev => "https://zed.dev/dev/",
+            ReleaseChannel::Nightly => "https://zed.dev/nightly/",
+            ReleaseChannel::Preview => "https://zed.dev/preview/",
+            ReleaseChannel::Stable => "https://zed.dev/",
+        }
+    }
+
+    pub fn release_query_param(&self) -> Option<&'static str> {
+        match self {
+            Self::Dev => None,
+            Self::Nightly => Some("nightly=1"),
+            Self::Preview => Some("preview=1"),
+            Self::Stable => None,
+        }
+    }
+}
+
+pub fn parse_zed_link(link: &str) -> Option<&str> {
+    for release in [
+        ReleaseChannel::Dev,
+        ReleaseChannel::Nightly,
+        ReleaseChannel::Preview,
+        ReleaseChannel::Stable,
+    ] {
+        if let Some(stripped) = link.strip_prefix(release.link_prefix()) {
+            return Some(stripped);
+        }
+        if let Some(stripped) = link.strip_prefix(release.url_scheme()) {
+            return Some(stripped);
+        }
+    }
+    None
+}