From 91901fac9659694d6074ef3a3e2613d60c27088d Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Sun, 1 Mar 2020 17:52:44 +0100
Subject: Add viewer for viewing all entries from an iterator

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
---
 lib/entry/libimagentryview/src/viewer.rs | 66 ++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/lib/entry/libimagentryview/src/viewer.rs b/lib/entry/libimagentryview/src/viewer.rs
index 902c9b7f..ca599e15 100644
--- a/lib/entry/libimagentryview/src/viewer.rs
+++ b/lib/entry/libimagentryview/src/viewer.rs
@@ -21,6 +21,7 @@ use std::io::Write;
 use std::ops::Deref;
 
 use libimagstore::store::Entry;
+use libimagstore::store::FileLockEntry;
 
 use crate::error::Result;
 
@@ -76,3 +77,68 @@ impl<I, E> ViewFromIter for I
     }
 }
 
+pub trait IntoViewIter<V, W, F, T>
+    where Self: Iterator<Item = T> + Sized,
+          V: Viewer,
+          W: Write,
+          F: Fn(&T) -> Option<&FileLockEntry>,
+          T: Sized,
+{
+    fn view_all_if(self, v: V, sink: &mut W, func: F) -> ViewIter<Self, V, W, F, T> {
+        ViewIter {
+            inner: self,
+            viewer: v,
+            func,
+            sink,
+        }
+    }
+}
+
+impl<I, V, W, F, T> IntoViewIter<V, W, F, T> for I
+    where I: Iterator<Item = T>,
+          V: Viewer,
+          W: Write,
+          F: Fn(&T) -> Option<&FileLockEntry>,
+          T: Sized,
+{
+    // default impl
+}
+
+
+pub struct ViewIter<'a, I, V, W, F, T>
+    where I: Iterator<Item = T>,
+          V: Viewer,
+          W: Write,
+          F: Fn(&T) -> Option<&FileLockEntry>,
+          T: Sized,
+{
+    inner: I,
+    viewer: V,
+    func: F,
+    sink: &'a mut W
+}
+
+impl<'a, I, V, W, F, T> Iterator for ViewIter<'a, I, V, W, F, T>
+    where I: Iterator<Item = T>,
+          V: Viewer,
+          W: Write,
+          F: Fn(&T) -> Option<&FileLockEntry>,
+          T: Sized,
+{
+    type Item = failure::Fallible<T>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(next) = self.inner.next() {
+            if let Some(entry) = (self.func)(&next) {
+                if let Err(e) = self.viewer.view_entry(&entry, self.sink) {
+                    return Some(Err(e).map_err(failure::Error::from))
+                }
+            }
+
+            return Some(Ok(next))
+        }
+
+        None
+    }
+}
+
-- 
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