Add Filter trait and operators

libimagentryfilter/src/filter.rs

@@ -0,0 +1,30 @@
+use libimagstore::store::Entry;
+
+pub use ops::and::And;
+pub use ops::not::Not;
+pub use ops::or::Or;
+
+pub trait Filter {
+
+    fn filter(&self, &Entry) -> bool;
+
+    fn not(self) -> Not
+        where Self: Sized + 'static
+    {
+        Not::new(Box::new(self))
+    }
+
+    fn or(self, other: Box<Filter>) -> Or
+        where Self: Sized + 'static
+    {
+        Or::new(Box::new(self), other)
+    }
+
+    fn and(self, other: Box<Filter>) -> And
+        where Self: Sized + 'static
+    {
+        And::new(Box::new(self), other)
+    }
+
+}
+

libimagentryfilter/src/ops/and.rs

@@ -0,0 +1,24 @@
+use libimagstore::store::Entry;
+
+use filter::Filter;
+
+pub struct And {
+    a: Box<Filter>,
+    b: Box<Filter>
+}
+
+impl And {
+
+    pub fn new(a: Box<Filter>, b: Box<Filter>) -> And {
+        And { a: a, b: b }
+    }
+
+}
+
+impl Filter for And {
+
+    fn filter(&self, e: &Entry) -> bool {
+        self.a.filter(e) && self.b.filter(e)
+    }
+
+}

libimagentryfilter/src/ops/not.rs

@@ -0,0 +1,23 @@
+use libimagstore::store::Entry;
+
+use filter::Filter;
+
+pub struct Not {
+    a: Box<Filter>
+}
+
+impl Not {
+
+    pub fn new(a: Box<Filter>) -> Not {
+        Not { a: a }
+    }
+
+}
+
+impl Filter for Not {
+
+    fn filter(&self, e: &Entry) -> bool {
+        !self.a.filter(e)
+    }
+
+}

libimagentryfilter/src/ops/or.rs

@@ -0,0 +1,24 @@
+use libimagstore::store::Entry;
+
+use filter::Filter;
+
+pub struct Or {
+    a: Box<Filter>,
+    b: Box<Filter>
+}
+
+impl Or {
+
+    pub fn new(a: Box<Filter>, b: Box<Filter>) -> Or {
+        Or { a: a, b: b }
+    }
+
+}
+
+impl Filter for Or {
+
+    fn filter(&self, e: &Entry) -> bool {
+        self.a.filter(e) || self.b.filter(e)
+    }
+
+}