2 files changed, 122 insertions, 0 deletions
diff --git a/src/package/dependency/condition.rs b/src/package/dependency/condition.rs
new file mode 100644
index 0000000..df65a5c
--- /dev/null
+++ b/src/package/dependency/condition.rs
@@ -0,0 +1,120 @@
+//
+// Copyright (c) 2020-2021 science+computing ag and other contributors
+//
+// This program and the accompanying materials are made
+// available under the terms of the Eclipse Public License 2.0
+// which is available at https://www.eclipse.org/legal/epl-2.0/
+//
+// SPDX-License-Identifier: EPL-2.0
+//
+
+use std::collections::HashMap;
+
+use serde::Deserialize;
+
+use crate::util::EnvironmentVariableName;
+
+/// The Condition type
+///
+/// This type represents a condition whether a dependency should be included in the package tree or
+/// not.
+///
+/// Right now, we are supporting condition by environment (set or equal) or whether a specific
+/// build image is used.
+/// All these settings are optional, of course.
+///
+#[derive(Deserialize, Clone, Debug)]
+pub struct Condition {
+    #[serde(rename = "has_env", skip_serializing_if = "Option::is_none")]
+    has_env: Option<OneOrMore<EnvironmentVariableName>>,
+
+    #[serde(rename = "env_eq", skip_serializing_if = "Option::is_none")]
+    env_eq: Option<HashMap<EnvironmentVariableName, String>>,
+
+    #[serde(rename = "in_image", skip_serializing_if = "Option::is_none")]
+    in_image: Option<OneOrMore<String>>,
+}
+
+
+/// Helper type for supporting Vec<T> and T in value
+/// position of Condition
+#[cfg_attr(test, derive(Eq, PartialEq))]
+#[derive(Deserialize, Clone, Debug)]
+#[serde(untagged)]
+pub enum OneOrMore<T: Sized> {
+    One(T),
+    More(Vec<T>),
+}
+
+impl<T: Sized> Into<Vec<T>> for OneOrMore<T> {
+    fn into(self) -> Vec<T> {
+        match self {
+            OneOrMore::One(o) => vec![o],
+            OneOrMore::More(m) => m,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_has_env_deserialization() {
+        let s = r#"has_env = "foo""#;
+        let c: Condition = toml::from_str(s).expect("Deserializing has_env");
+
+        assert_eq!(c.has_env.unwrap(), OneOrMore::<EnvironmentVariableName>::One(EnvironmentVariableName::from("foo")));
+        assert!(c.env_eq.is_none());
+        assert!(c.in_image.is_none());
+    }
+
+    #[test]
+    fn test_has_env_list_deserialization() {
+        let s = r#"has_env = ["foo", "bar"]"#;
+        let c: Condition = toml::from_str(s).expect("Deserializing has_env");
+
+        assert_eq!(c.has_env.unwrap(), {
+            OneOrMore::<EnvironmentVariableName>::More({
+                vec![EnvironmentVariableName::from("foo"), EnvironmentVariableName::from("bar")]
+            })
+        });
+        assert!(c.env_eq.is_none());
+        assert!(c.in_image.is_none());
+    }
+
+    #[test]
+    fn test_env_eq_deserialization() {
+        let s = r#"env_eq = { "foo" = "bar" }"#;
+        let c: Condition = toml::from_str(s).expect("Deserializing has_env");
+
+        assert!(c.has_env.is_none());
+        assert_eq!(c.env_eq.unwrap(), {
+            let mut hm = HashMap::new();
+            hm.insert(EnvironmentVariableName::from("foo"), String::from("bar"));
+            hm
+        });
+        assert!(c.in_image.is_none());
+    }
+
+    #[test]
+    fn test_in_image_deserialization() {
+        let s = r#"in_image = "foo""#;
+        let c: Condition = toml::from_str(s).expect("Deserializing has_env");
+
+        assert!(c.has_env.is_none());
+        assert!(c.env_eq.is_none());
+        assert_eq!(c.in_image.unwrap(), OneOrMore::<String>::One(String::from("foo")));
+    }
+
+    #[test]
+    fn test_in_image_list_deserialization() {
+        let s = r#"in_image = ["foo"]"#;
+        let c: Condition = toml::from_str(s).expect("Deserializing has_env");
+
+        assert!(c.has_env.is_none());
+        assert!(c.env_eq.is_none());
+        assert_eq!(c.in_image.unwrap(), OneOrMore::<String>::More(vec![String::from("foo")]));
+    }
+
+}
diff --git a/src/package/dependency/mod.rs b/src/package/dependency/mod.rs
index 37cb82b..8195dd1 100644
--- a/src/package/dependency/mod.rs
+++ b/src/package/dependency/mod.rs
@@ -24,6 +24,8 @@ pub use build::*;
 mod runtime;
 pub use runtime::*;
 
+mod condition;
+
 pub trait StringEqual {
     fn str_equal(&self, s: &str) -> bool;
 }