Merge pull request 's3 api: refactoring and bug fix in ListObjects' (#655) from fix-list-objects into main

Reviewed-on: Deuxfleurs/garage#655

src/api/s3/list.rs

@@ -426,8 +426,10 @@ where
 		// Drop the first key if needed
 		// Only AfterKey requires it according to the S3 spec and our implem.
 		match (&cursor, iter.peek()) {
-			(RangeBegin::AfterKey { key }, Some(object)) if &object.key == key => iter.next(),
-			(_, _) => None,
+			(RangeBegin::AfterKey { key }, Some(object)) if &object.key == key => {
+				iter.next();
+			}
+			_ => (),
 		};
 
 		while let Some(object) = iter.peek() {
@@ -436,16 +438,22 @@ where
 				return Ok(None);
 			}
 
-			cursor = match acc.extract(query, &cursor, &mut iter) {
-				ExtractionResult::Extracted { key } => RangeBegin::AfterKey { key },
+			match acc.extract(query, &cursor, &mut iter) {
+				ExtractionResult::Extracted { key } => {
+					cursor = RangeBegin::AfterKey { key };
+				}
 				ExtractionResult::SkipTo { key, fallback_key } => {
-					RangeBegin::IncludingKey { key, fallback_key }
+					cursor = RangeBegin::IncludingKey { key, fallback_key };
 				}
 				ExtractionResult::FilledAtUpload { key, upload } => {
-					return Ok(Some(RangeBegin::AfterUpload { key, upload }))
+					return Ok(Some(RangeBegin::AfterUpload { key, upload }));
+				}
+				ExtractionResult::Filled => {
+					return Ok(Some(cursor));
+				}
+				ExtractionResult::NoMore => {
+					return Ok(None);
 				}
-				ExtractionResult::Filled => return Ok(Some(cursor)),
-				ExtractionResult::NoMore => return Ok(None),
 			};
 		}
 
@@ -519,8 +527,8 @@ fn fetch_part_info<'a>(
 /// This key can be the prefix in the base case, or intermediate
 /// points in the dataset if we are continuing a previous listing.
 impl ListObjectsQuery {
-	fn build_accumulator(&self) -> Accumulator<String, ObjectInfo> {
-		Accumulator::<String, ObjectInfo>::new(self.common.page_size)
+	fn build_accumulator(&self) -> ObjectAccumulator {
+		ObjectAccumulator::new(self.common.page_size)
 	}
 
 	fn begin(&self) -> Result<RangeBegin, Error> {
@@ -529,9 +537,10 @@ impl ListObjectsQuery {
 				// In V2 mode, the continuation token is defined as an opaque
 				// string in the spec, so we can do whatever we want with it.
 				// In our case, it is defined as either [ or ] (for include
+				// or exclude), followed by a base64-encoded string
 				// representing the key to start with.
-				(Some(token), _) => match &token[..1] {
-					"[" => Ok(RangeBegin::IncludingKey {
+				(Some(token), _) => match &token.get(..1) {
+					Some("[") => Ok(RangeBegin::IncludingKey {
 						key: String::from_utf8(
 							BASE64_STANDARD
 								.decode(token[1..].as_bytes())
@@ -539,7 +548,7 @@ impl ListObjectsQuery {
 						)?,
 						fallback_key: None,
 					}),
-					"]" => Ok(RangeBegin::AfterKey {
+					Some("]") => Ok(RangeBegin::AfterKey {
 						key: String::from_utf8(
 							BASE64_STANDARD
 								.decode(token[1..].as_bytes())
@@ -580,8 +589,8 @@ impl ListObjectsQuery {
 }
 
 impl ListMultipartUploadsQuery {
-	fn build_accumulator(&self) -> Accumulator<Uuid, UploadInfo> {
-		Accumulator::<Uuid, UploadInfo>::new(self.common.page_size)
+	fn build_accumulator(&self) -> UploadAccumulator {
+		UploadAccumulator::new(self.common.page_size)
 	}
 
 	fn begin(&self) -> Result<RangeBegin, Error> {
@@ -665,6 +674,7 @@ impl<K: std::cmp::Ord, V> Accumulator<K, V> {
 			Some(p) => p,
 			None => return None,
 		};
+		assert!(pfx.starts_with(&query.prefix));
 
 		// Try to register this prefix
 		// If not possible, we can return early
@@ -675,8 +685,11 @@ impl<K: std::cmp::Ord, V> Accumulator<K, V> {
 		// We consume the whole common prefix from the iterator
 		let mut last_pfx_key = &object.key;
 		loop {
-			last_pfx_key = match objects.peek() {
-				Some(o) if o.key.starts_with(pfx) => &o.key,
+			match objects.peek() {
+				Some(o) if o.key.starts_with(pfx) => {
+					last_pfx_key = &o.key;
+					objects.next();
+				}
 				Some(_) => {
 					return Some(ExtractionResult::Extracted {
 						key: last_pfx_key.to_owned(),
@@ -692,8 +705,6 @@ impl<K: std::cmp::Ord, V> Accumulator<K, V> {
 					}
 				}
 			};
-
-			objects.next();
 		}
 	}
 
@@ -708,28 +719,26 @@ impl<K: std::cmp::Ord, V> Accumulator<K, V> {
 		}
 
 		// Otherwise, we need to check if we can add it
-		match self.is_full() {
-			true => false,
-			false => {
+		if self.is_full() {
+			false
+		} else {
 			self.common_prefixes.insert(key);
 			true
 		}
 	}
-	}
 
 	fn try_insert_entry(&mut self, key: K, value: V) -> bool {
 		// It is impossible to add twice a key, this is an error
 		assert!(!self.keys.contains_key(&key));
 
-		match self.is_full() {
-			true => false,
-			false => {
+		if self.is_full() {
+			false
+		} else {
 			self.keys.insert(key, value);
 			true
 		}
 	}
 }
-}
 
 impl ExtractAccumulator for ObjectAccumulator {
 	fn extract<'a>(
@@ -743,6 +752,7 @@ impl ExtractAccumulator for ObjectAccumulator {
 		}
 
 		let object = objects.next().expect("This iterator can not be empty as it is checked earlier in the code. This is a logic bug, please report it.");
+		assert!(object.key.starts_with(&query.prefix));
 
 		let version = match object.versions().iter().find(|x| x.is_data()) {
 			Some(v) => v,