Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/is_ci/src/lib.rs

@@ -0,0 +1,69 @@
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Once;
+
+static INIT: Once = Once::new();
+static IS_CI: AtomicBool = AtomicBool::new(false);
+
+/// Returns true if the current environment is found to probably be a CI
+/// environment or service. That's it, that's all it does.
+#[deprecated(since = "1.1.0", note = "Use `cached` or `uncached` instead")]
+pub fn is_ci() -> bool {
+    uncached()
+}
+
+/// Returns true if the current environment is found to probably be a CI
+/// environment or service, and caches the result for future calls. If you
+/// expect the environment to change, use [uncached].
+pub fn cached() -> bool {
+    INIT.call_once(|| IS_CI.store(uncached(), Ordering::Relaxed));
+    IS_CI.load(Ordering::Relaxed)
+}
+
+/// Returns true if the current environment is found to probably be a CI
+/// environment or service. If you expect to call this multiple times without
+/// the environment changing, use [cached].
+pub fn uncached() -> bool {
+    let ci_var = std::env::var("CI");
+    ci_var == Ok("true".into())
+        || ci_var == Ok("1".into())
+        || check("CI_NAME")
+        || check("GITHUB_ACTION")
+        || check("GITLAB_CI")
+        || check("NETLIFY")
+        || check("TRAVIS")
+        || matches!(std::env::var("NODE"), Ok(node) if node.ends_with("//heroku/node/bin/node"))
+        || check("CODEBUILD_SRC_DIR")
+        || check("BUILDER_OUTPUT")
+        || check("GITLAB_DEPLOYMENT")
+        || check("NOW_GITHUB_DEPLOYMENT")
+        || check("NOW_BUILDER")
+        || check("BITBUCKET_DEPLOYMENT")
+        || check("GERRIT_PROJECT")
+        || check("SYSTEM_TEAMFOUNDATIONCOLLECTIONURI")
+        || check("BITRISE_IO")
+        || check("BUDDY_WORKSPACE_ID")
+        || check("BUILDKITE")
+        || check("CIRRUS_CI")
+        || check("APPVEYOR")
+        || check("CIRCLECI")
+        || check("SEMAPHORE")
+        || check("DRONE")
+        || check("DSARI")
+        || check("TDDIUM")
+        || check("STRIDER")
+        || check("TASKCLUSTER_ROOT_URL")
+        || check("JENKINS_URL")
+        || check("bamboo.buildKey")
+        || check("GO_PIPELINE_NAME")
+        || check("HUDSON_URL")
+        || check("WERCKER")
+        || check("MAGNUM")
+        || check("NEVERCODE")
+        || check("RENDER")
+        || check("SAIL_CI")
+        || check("SHIPPABLE")
+}
+
+fn check(name: &str) -> bool {
+    std::env::var(name).is_ok()
+}