Rewrite Store::entries()

This patch rewrites the Store::entries() function to not be collecting
the iterator.

It therefore introduces a new, internal, iterator type which creates the
StoreId objects from the pathes the PathIterator yields internally.

With this patch, the Store iterator interface changes, as the iterators
now yield `Result<StoreId, StoreError>` instead of `StoreId`.
This is necessary, as the internal conversion errors shouldn't be
hidden.

Of course, the iterator types (like the StoreGetIterator and so on)
should hold a Result<StoreId> internally as well, and also yield
appropritely. This was changed in this commit, too.

5 files changed, 47 insertions, 29 deletions

diff --git a/lib/core/libimagstore/src/file_abstraction/iter.rs b/lib/core/libimagstore/src/file_abstraction/iter.rs
index c0bd8b5f..d7ae82d9 100644
--- a/lib/core/libimagstore/src/file_abstraction/iter.rs
+++ b/lib/core/libimagstore/src/file_abstraction/iter.rs
@@ -20,6 +20,7 @@
 use std::path::PathBuf;
 
 use error::Result;
+use storeid::StoreId;
 
 /// A wrapper for an iterator over `PathBuf`s
 pub struct PathIterator(Box<Iterator<Item = Result<PathBuf>>>);
@@ -30,6 +31,10 @@ impl PathIterator {
         PathIterator(iter)
     }
 
+    pub fn store_id_constructing(self, storepath: PathBuf) -> StoreIdConstructingIterator {
+        StoreIdConstructingIterator(self, storepath)
+    }
+
 }
 
 impl Iterator for PathIterator {
@@ -41,3 +46,29 @@ impl Iterator for PathIterator {
 
 }
 
+
+/// Helper type for constructing StoreIds from a PathIterator.
+///
+/// Automatically ignores non-files.
+pub struct StoreIdConstructingIterator(PathIterator, PathBuf);
+
+impl Iterator for StoreIdConstructingIterator {
+    type Item = Result<StoreId>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(next) = self.0.next() {
+            match next {
+                Err(e)  => return Some(Err(e)),
+                Ok(next) => if next.is_file() {
+                    return Some(StoreId::from_full_path(&self.1, next))
+                } else {
+                    continue
+                }
+            }
+        }
+
+        None
+    }
+
+}
+
diff --git a/lib/core/libimagstore/src/file_abstraction/mod.rs b/lib/core/libimagstore/src/file_abstraction/mod.rs
index 893b8ca2..a3172735 100644
--- a/lib/core/libimagstore/src/file_abstraction/mod.rs
+++ b/lib/core/libimagstore/src/file_abstraction/mod.rs
@@ -27,7 +27,7 @@ use storeid::StoreId;
 
 mod fs;
 mod inmemory;
-mod iter;
+pub(crate) mod iter;
 
 pub use self::fs::FSFileAbstraction;
 pub use self::fs::FSFileAbstractionInstance;
diff --git a/lib/core/libimagstore/src/iter.rs b/lib/core/libimagstore/src/iter.rs
index 0171a93b..63100470 100644
--- a/lib/core/libimagstore/src/iter.rs
+++ b/lib/core/libimagstore/src/iter.rs
@@ -32,10 +32,10 @@ macro_rules! mk_iterator {
         use store::Store;
         use error::Result;
 
-        pub struct $itername<'a>(Box<Iterator<Item = StoreId> + 'a>, &'a Store);
+        pub struct $itername<'a>(Box<Iterator<Item = Result<StoreId>> + 'a>, &'a Store);
 
         impl<'a> $itername<'a> {
-            pub fn new(inner: Box<Iterator<Item = StoreId> + 'a>, store: &'a Store) -> Self {
+            pub fn new(inner: Box<Iterator<Item = Result<StoreId>> + 'a>, store: &'a Store) -> Self {
                 $itername(inner, store)
             }
         }
@@ -44,7 +44,7 @@ macro_rules! mk_iterator {
             type Item = Result<$yield>;
 
             fn next(&mut self) -> Option<Self::Item> {
-                self.0.next().map(|id| $fun(id, self.1))
+                self.0.next().map(|id| $fun(id?, self.1))
             }
         }
 
@@ -53,7 +53,7 @@ macro_rules! mk_iterator {
         }
 
         impl<'a, I> $extname<'a> for I
-            where I: Iterator<Item = StoreId> + 'a
+            where I: Iterator<Item = Result<StoreId>> + 'a
         {
             fn $extfnname(self, store: &'a Store) -> $itername<'a> {
                 $itername(Box::new(self), store)
diff --git a/lib/core/libimagstore/src/store.rs b/lib/core/libimagstore/src/store.rs
index 7edf3f05..c401594a 100644
--- a/lib/core/libimagstore/src/store.rs
+++ b/lib/core/libimagstore/src/store.rs
@@ -741,25 +741,12 @@ impl Store {
     }
 
     /// Get _all_ entries in the store (by id as iterator)
-    pub fn entries<'a>(&'a self) -> Result<StoreIdIteratorWithStore<'a>> {
+    pub fn entries(&self) -> Result<StoreIdIteratorWithStore> {
         self.backend
             .pathes_recursively(self.path().clone())
-            .and_then(|iter| {
-                let mut elems = vec![];
-                for element in iter {
-                    let is_file = {
-                        let mut base = self.path().clone();
-                        base.push(element.clone());
-                        self.backend.is_file(&base)?
-                    };
-
-                    if is_file {
-                        let sid = StoreId::from_full_path(self.path(), element)?;
-                        elems.push(sid);
-                    }
-                }
-                Ok(StoreIdIteratorWithStore::new(Box::new(elems.into_iter()), self))
-            })
+            .map(|i| i.store_id_constructing(self.path().clone()))
+            .map(Box::new)
+            .map(|it| StoreIdIteratorWithStore::new(it, self))
     }
 
     /// Gets the path where this store is on the disk
diff --git a/lib/core/libimagstore/src/storeid.rs b/lib/core/libimagstore/src/storeid.rs
index 2bcd9ba7..80e1b35d 100644
--- a/lib/core/libimagstore/src/storeid.rs
+++ b/lib/core/libimagstore/src/storeid.rs
@@ -241,7 +241,7 @@ macro_rules! module_entry_path_mod {
 }
 
 pub struct StoreIdIterator {
-    iter: Box<Iterator<Item = StoreId>>,
+    iter: Box<Iterator<Item = Result<StoreId>>>,
 }
 
 impl Debug for StoreIdIterator {
@@ -254,16 +254,16 @@ impl Debug for StoreIdIterator {
 
 impl StoreIdIterator {
 
-    pub fn new(iter: Box<Iterator<Item = StoreId>>) -> StoreIdIterator {
+    pub fn new(iter: Box<Iterator<Item = Result<StoreId>>>) -> StoreIdIterator {
         StoreIdIterator { iter }
     }
 
 }
 
 impl Iterator for StoreIdIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
-    fn next(&mut self) -> Option<StoreId> {
+    fn next(&mut self) -> Option<Self::Item> {
         self.iter.next()
     }
 
@@ -280,16 +280,16 @@ impl<'a> Deref for StoreIdIteratorWithStore<'a> {
 }
 
 impl<'a> Iterator for StoreIdIteratorWithStore<'a> {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
-    fn next(&mut self) -> Option<StoreId> {
+    fn next(&mut self) -> Option<Self::Item> {
         self.0.next()
     }
 }
 
 impl<'a> StoreIdIteratorWithStore<'a> {
 
-    pub fn new(iter: Box<Iterator<Item = StoreId>>, store: &'a Store) -> Self {
+    pub fn new(iter: Box<Iterator<Item = Result<StoreId>>>, store: &'a Store) -> Self {
         StoreIdIteratorWithStore(StoreIdIterator::new(iter), store)
     }