fix: Make the merge operator work

src/blob/mod.rs

@@ -11,6 +11,7 @@ use std::fmt;
 use serde::ser::{Serialize, Serializer, SerializeTuple};
 use serde::de::{self, Deserialize, Deserializer, SeqAccess, Visitor};
 
+#[derive(Debug)]
 pub enum Blob {
     Positive(PositiveBlob),
     Negative(NegativeBlob),

src/blob/negative/blob.rs

@@ -1,11 +1,13 @@
-use std::path::Path;
 use std::error::Error;
+use std::path::Path;
+use std::fmt;
 
 use serde::de::{self, Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
 use crate::data::DocIds;
 use crate::DocumentId;
 
+#[derive(Default)]
 pub struct NegativeBlob {
     doc_ids: DocIds,
 }
@@ -42,6 +44,14 @@ impl AsRef<[DocumentId]> for NegativeBlob {
     }
 }
 
+impl fmt::Debug for NegativeBlob {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "NegativeBlob(")?;
+        f.debug_list().entries(self.as_ref()).finish()?;
+        write!(f, ")")
+    }
+}
+
 impl Serialize for NegativeBlob {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
         self.doc_ids.serialize(serializer)

src/blob/ops.rs

@@ -46,8 +46,8 @@ impl OpBuilder {
 
     pub fn merge(self) -> Result<PositiveBlob, Box<Error>> {
         let groups = GroupBy::new(&self.blobs, blob_same_sign);
-        let mut positives = Vec::new();
-        let mut negatives = Vec::new();
+        let mut aggregated = Vec::new();
+
         for blobs in groups {
             match blobs[0].sign() {
                 Sign::Positive => {
@@ -66,7 +66,7 @@ impl OpBuilder {
                     }
                     let (map, doc_indexes) = builder.into_inner().unwrap();
                     let blob = PositiveBlob::from_bytes(map, doc_indexes).unwrap();
-                    positives.push(blob);
+                    aggregated.push(Blob::Positive(blob));
                 },
                 Sign::Negative => {
                     let mut op_builder = negative::OpBuilder::with_capacity(blobs.len());
@@ -74,14 +74,20 @@ impl OpBuilder {
                         op_builder.push(unwrap_negative(blob));
                     }
                     let blob = op_builder.union().into_negative_blob();
-                    negatives.push(blob);
+                    aggregated.push(Blob::Negative(blob));
                 },
             }
         }
 
-        let mut zipped = positives.into_iter().zip(negatives);
         let mut buffer = Vec::new();
-        zipped.try_fold(PositiveBlob::default(), |base, (positive, negative)| {
+        aggregated.chunks(2).try_fold(PositiveBlob::default(), |base, slice| {
+            let negative = NegativeBlob::default();
+            let (positive, negative) = match slice {
+                [a, b] => (unwrap_positive(a), unwrap_negative(b)),
+                [a] => (unwrap_positive(a), &negative),
+                _ => unreachable!(),
+            };
+
             let mut builder = PositiveBlobBuilder::memory();
             let doc_ids = Set::new_unchecked(negative.as_ref());
 

src/blob/positive/blob.rs

@@ -37,7 +37,7 @@ impl PositiveBlob {
     }
 
     pub fn get<K: AsRef<[u8]>>(&self, key: K) -> Option<&[DocIndex]> {
-        self.map.get(key).and_then(|index| self.indexes.get(index))
+        self.map.get(key).map(|index| &self.indexes[index as usize])
     }
 
     pub fn as_map(&self) -> &Map {
@@ -53,6 +53,22 @@ impl PositiveBlob {
     }
 }
 
+impl fmt::Debug for PositiveBlob {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "PositiveBlob([")?;
+        let mut stream = self.into_stream();
+        let mut first = true;
+        while let Some((k, v)) = stream.next() {
+            if !first {
+                write!(f, ", ")?;
+            }
+            first = false;
+            write!(f, "({}, {:?})", String::from_utf8_lossy(k), v)?;
+        }
+        write!(f, "])")
+    }
+}
+
 impl<'m, 'a> IntoStreamer<'a> for &'m PositiveBlob {
     type Item = (&'a [u8], &'a [DocIndex]);
     /// The type of the stream to be constructed.
@@ -78,8 +94,7 @@ impl<'m, 'a> Streamer<'a> for PositiveBlobStream<'m> {
     fn next(&'a mut self) -> Option<Self::Item> {
         match self.map_stream.next() {
             Some((input, index)) => {
-                let doc_indexes = self.doc_indexes.get(index);
-                let doc_indexes = doc_indexes.expect("BUG: could not find document indexes");
+                let doc_indexes = &self.doc_indexes[index as usize];
                 Some((input, doc_indexes))
             },
             None => None,
@@ -91,7 +106,7 @@ impl Serialize for PositiveBlob {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
         let mut tuple = serializer.serialize_tuple(2)?;
         tuple.serialize_element(&self.map.as_fst().to_vec())?;
-        tuple.serialize_element(&self.indexes)?;
+        tuple.serialize_element(&self.indexes.to_vec())?;
         tuple.end()
     }
 }
@@ -162,7 +177,9 @@ impl<W: Write, X: Write> PositiveBlobBuilder<W, X> {
     /// then an error is returned. Similarly, if there was a problem writing
     /// to the underlying writer, an error is returned.
     // FIXME what if one write doesn't work but the other do ?
-    pub fn insert(&mut self, key: &[u8], doc_indexes: &[DocIndex]) -> Result<(), Box<Error>> {
+    pub fn insert<K>(&mut self, key: K, doc_indexes: &[DocIndex]) -> Result<(), Box<Error>>
+    where K: AsRef<[u8]>,
+    {
         self.map.insert(key, self.value)?;
         self.indexes.insert(doc_indexes)?;
         self.value += 1;
@@ -179,3 +196,58 @@ impl<W: Write, X: Write> PositiveBlobBuilder<W, X> {
         Ok((map, indexes))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::error::Error;
+
+    #[test]
+    fn serialize_deserialize() -> Result<(), Box<Error>> {
+        let a = DocIndex { document_id: 0, attribute: 3, attribute_index: 11 };
+        let b = DocIndex { document_id: 1, attribute: 4, attribute_index: 21 };
+        let c = DocIndex { document_id: 2, attribute: 8, attribute_index: 2 };
+
+        let mut builder = PositiveBlobBuilder::memory();
+
+        builder.insert("aaa", &[a])?;
+        builder.insert("aab", &[a, b, c])?;
+        builder.insert("aac", &[a, c])?;
+
+        let (map_bytes, indexes_bytes) = builder.into_inner()?;
+        let positive_blob = PositiveBlob::from_bytes(map_bytes, indexes_bytes)?;
+
+        assert_eq!(positive_blob.get("aaa"), Some(&[a][..]));
+        assert_eq!(positive_blob.get("aab"), Some(&[a, b, c][..]));
+        assert_eq!(positive_blob.get("aac"), Some(&[a, c][..]));
+        assert_eq!(positive_blob.get("aad"), None);
+
+        Ok(())
+    }
+
+    #[test]
+    fn serde_serialize_deserialize() -> Result<(), Box<Error>> {
+        let a = DocIndex { document_id: 0, attribute: 3, attribute_index: 11 };
+        let b = DocIndex { document_id: 1, attribute: 4, attribute_index: 21 };
+        let c = DocIndex { document_id: 2, attribute: 8, attribute_index: 2 };
+
+        let mut builder = PositiveBlobBuilder::memory();
+
+        builder.insert("aaa", &[a])?;
+        builder.insert("aab", &[a, b, c])?;
+        builder.insert("aac", &[a, c])?;
+
+        let (map_bytes, indexes_bytes) = builder.into_inner()?;
+        let positive_blob = PositiveBlob::from_bytes(map_bytes, indexes_bytes)?;
+
+        let bytes = bincode::serialize(&positive_blob)?;
+        let positive_blob: PositiveBlob = bincode::deserialize(&bytes)?;
+
+        assert_eq!(positive_blob.get("aaa"), Some(&[a][..]));
+        assert_eq!(positive_blob.get("aab"), Some(&[a, b, c][..]));
+        assert_eq!(positive_blob.get("aac"), Some(&[a, c][..]));
+        assert_eq!(positive_blob.get("aad"), None);
+
+        Ok(())
+    }
+}

src/blob/positive/ops.rs

@@ -106,9 +106,8 @@ impl<'m, 'a> fst::Streamer<'a> for $name<'m> {
 
                 let mut builder = SdOpBuilder::with_capacity(ivalues.len());
                 for ivalue in ivalues {
-                    let indexes = self.indexes[ivalue.index].get(ivalue.value);
-                    let indexes = indexes.expect("BUG: could not find document indexes");
-                    let set = Set::new_unchecked(indexes);
+                    let doc_indexes = &self.indexes[ivalue.index][ivalue.value as usize];
+                    let set = Set::new_unchecked(doc_indexes);
                     builder.push(set);
                 }
 

src/data/doc_ids.rs

@@ -10,7 +10,7 @@ use serde::ser::{Serialize, Serializer};
 use crate::DocumentId;
 use crate::data::Data;
 
-#[derive(Clone)]
+#[derive(Default, Clone)]
 pub struct DocIds {
     data: Data,
 }

src/data/doc_indexes.rs

@@ -1,12 +1,12 @@
 use std::slice::from_raw_parts;
 use std::io::{self, Write};
+use std::mem::size_of;
+use std::ops::Index;
 use std::path::Path;
 use std::sync::Arc;
-use std::mem;
 
 use fst::raw::MmapReadOnly;
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
-use serde::ser::{Serialize, Serializer, SerializeTuple};
 
 use crate::DocIndex;
 use crate::data::Data;
@@ -41,7 +41,7 @@ impl DocIndexes {
     }
 
     fn from_data(data: Data) -> io::Result<Self> {
-        let ranges_len_offset = data.len() - mem::size_of::<u64>();
+        let ranges_len_offset = data.len() - size_of::<u64>();
         let ranges_len = (&data[ranges_len_offset..]).read_u64::<LittleEndian>()?;
         let ranges_len = ranges_len as usize;
 
@@ -53,7 +53,18 @@ impl DocIndexes {
         Ok(DocIndexes { ranges, indexes })
     }
 
-    pub fn get(&self, index: u64) -> Option<&[DocIndex]> {
+    pub fn to_vec(&self) -> Vec<u8> {
+        let capacity = self.indexes.len() + self.ranges.len() + size_of::<u64>();
+        let mut bytes = Vec::with_capacity(capacity);
+
+        bytes.extend_from_slice(&self.indexes);
+        bytes.extend_from_slice(&self.ranges);
+        bytes.write_u64::<LittleEndian>(self.ranges.len() as u64).unwrap();
+
+        bytes
+    }
+
+    pub fn get(&self, index: usize) -> Option<&[DocIndex]> {
         self.ranges().get(index as usize).map(|Range { start, end }| {
             let start = *start as usize;
             let end = *end as usize;
@@ -64,24 +75,26 @@ impl DocIndexes {
     fn ranges(&self) -> &[Range] {
         let slice = &self.ranges;
         let ptr = slice.as_ptr() as *const Range;
-        let len = slice.len() / mem::size_of::<Range>();
+        let len = slice.len() / size_of::<Range>();
         unsafe { from_raw_parts(ptr, len) }
     }
 
     fn indexes(&self) -> &[DocIndex] {
         let slice = &self.indexes;
         let ptr = slice.as_ptr() as *const DocIndex;
-        let len = slice.len() / mem::size_of::<DocIndex>();
+        let len = slice.len() / size_of::<DocIndex>();
         unsafe { from_raw_parts(ptr, len) }
     }
 }
 
-impl Serialize for DocIndexes {
-    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        let mut tuple = serializer.serialize_tuple(2)?;
-        tuple.serialize_element(self.ranges.as_ref())?;
-        tuple.serialize_element(self.indexes.as_ref())?;
-        tuple.end()
+impl Index<usize> for DocIndexes {
+    type Output = [DocIndex];
+
+    fn index(&self, index: usize) -> &Self::Output {
+        match self.get(index) {
+            Some(indexes) => indexes,
+            None => panic!("index {} out of range for a maximum of {} ranges", index, self.ranges().len()),
+        }
     }
 }
 
@@ -134,7 +147,7 @@ impl<W: Write> DocIndexesBuilder<W> {
 
 unsafe fn into_u8_slice<T>(slice: &[T]) -> &[u8] {
     let ptr = slice.as_ptr() as *const u8;
-    let len = slice.len() * mem::size_of::<T>();
+    let len = slice.len() * size_of::<T>();
     from_raw_parts(ptr, len)
 }
 
@@ -144,7 +157,7 @@ mod tests {
     use std::error::Error;
 
     #[test]
-    fn serialize_deserialize() -> Result<(), Box<Error>> {
+    fn builder_serialize_deserialize() -> Result<(), Box<Error>> {
         let a = DocIndex { document_id: 0, attribute: 3, attribute_index: 11 };
         let b = DocIndex { document_id: 1, attribute: 4, attribute_index: 21 };
         let c = DocIndex { document_id: 2, attribute: 8, attribute_index: 2 };
@@ -158,9 +171,31 @@ mod tests {
         let bytes = builder.into_inner()?;
         let docs = DocIndexes::from_bytes(bytes)?;
 
-        assert_eq!(docs.get(0).unwrap(), &[a]);
-        assert_eq!(docs.get(1).unwrap(), &[a, b, c]);
-        assert_eq!(docs.get(2).unwrap(), &[a, c]);
+        assert_eq!(docs.get(0), Some(&[a][..]));
+        assert_eq!(docs.get(1), Some(&[a, b, c][..]));
+        assert_eq!(docs.get(2), Some(&[a, c][..]));
+        assert_eq!(docs.get(3), None);
+
+        Ok(())
+    }
+
+    #[test]
+    fn serialize_deserialize() -> Result<(), Box<Error>> {
+        let a = DocIndex { document_id: 0, attribute: 3, attribute_index: 11 };
+        let b = DocIndex { document_id: 1, attribute: 4, attribute_index: 21 };
+        let c = DocIndex { document_id: 2, attribute: 8, attribute_index: 2 };
+
+        let mut builder = DocIndexesBuilder::memory();
+
+        builder.insert(&[a])?;
+        builder.insert(&[a, b, c])?;
+        builder.insert(&[a, c])?;
+
+        let builder_bytes = builder.into_inner()?;
+        let docs = DocIndexes::from_bytes(builder_bytes.clone())?;
+        let bytes = docs.to_vec();
+
+        assert_eq!(builder_bytes, bytes);
 
         Ok(())
     }

src/rank/ranked_stream.rs

@@ -86,7 +86,7 @@ where T: Deref<Target=DB>,
                 let is_exact = distance == 0 && input.len() == automaton.query_len();
 
                 let doc_indexes = self.blob.as_indexes();
-                let doc_indexes = doc_indexes.get(iv.value).expect("BUG: could not find document indexes");
+                let doc_indexes = &doc_indexes[iv.value as usize];
 
                 for doc_index in doc_indexes {
                     let match_ = Match {