SWIFT-493 Support passing in sessions to "drop" command

Sources/MongoSwift/MongoCollection.swift

@@ -87,8 +87,8 @@ public class MongoCollection<T: Codable> {
     /// Drops this collection from its parent database.
     /// - Throws:
     ///   - `ServerError.commandError` if an error occurs that prevents the command from executing.
-    public func drop() throws {
-        let operation = DropCollectionOperation(collection: self)
+    public func drop(session: ClientSession? = nil) throws {
+        let operation = DropCollectionOperation(collection: self, session: session)
         try operation.execute()
     }
 }

Sources/MongoSwift/MongoDatabase.swift

@@ -132,8 +132,8 @@ public class MongoDatabase {
     /// Drops this database.
     /// - Throws:
     ///   - `ServerError.commandError` if an error occurs that prevents the command from executing.
-    public func drop() throws {
-        let operation = DropDatabaseOperation(database: self)
+    public func drop(session: ClientSession? = nil) throws {
+        let operation = DropDatabaseOperation(database: self, session: session)
         try operation.execute()
     }
 

Sources/MongoSwift/Operations/DropCollectionOperation.swift

@@ -3,15 +3,25 @@ import mongoc
 /// An operation corresponding to a "drop" command on a MongoCollection.
 internal struct DropCollectionOperation<T: Codable>: Operation {
     private let collection: MongoCollection<T>
+    private let session: ClientSession?
 
-    internal init(collection: MongoCollection<T>) {
+    internal init(collection: MongoCollection<T>, session: ClientSession?) {
         self.collection = collection
+        self.session = session
     }
 
     internal func execute() throws {
+        let command: Document = ["drop": self.collection.name]
+        let opts = try encodeOptions(options: Document(), session: self.session)
+
+        var reply = Document()
         var error = bson_error_t()
-        guard mongoc_collection_drop(self.collection._collection, &error) else {
-            throw parseMongocError(error)
+        let success = withMutableBSONPointer(to: &reply) { replyPtr in
+            mongoc_collection_write_command_with_opts(
+                    self.collection._collection, command._bson, opts?._bson, replyPtr, &error)
+        }
+        guard success else {
+            throw getErrorFromReply(bsonError: error, from: reply)
         }
     }
 }

Sources/MongoSwift/Operations/DropDatabaseOperation.swift

@@ -3,15 +3,25 @@ import mongoc
 /// An operation corresponding to a "drop" command on a MongoDatabase.
 internal struct DropDatabaseOperation: Operation {
     private let database: MongoDatabase
+    private let session: ClientSession?
 
-    internal init(database: MongoDatabase) {
+    internal init(database: MongoDatabase, session: ClientSession?) {
         self.database = database
+        self.session = session
     }
 
     internal func execute() throws {
+        let command: Document = ["dropDatabase": 1]
+        let opts = try encodeOptions(options: Document(), session: self.session)
+
+        var reply = Document()
         var error = bson_error_t()
-        guard mongoc_database_drop(self.database._database, &error) else {
-            throw parseMongocError(error)
+        let success = withMutableBSONPointer(to: &reply) { replyPtr in
+            mongoc_database_write_command_with_opts(
+                    self.database._database, command._bson, opts?._bson, replyPtr, &error)
+        }
+        guard success else {
+            throw getErrorFromReply(bsonError: error, from: reply)
         }
     }
 }

Tests/MongoSwiftTests/ClientSessionTests.swift

@@ -51,14 +51,16 @@ final class ClientSessionTests: MongoSwiftTestCase {
         (name: "listIndexes", body: { _ = try $0.listIndexes(session: $1).next() }),
         (name: "findOneAndDelete", body: { _ = try $0.findOneAndDelete([:], session: $1) }),
         (name: "findOneAndReplace", body: { _ = try $0.findOneAndReplace(filter: [:], replacement: [:], session: $1) }),
-        (name: "findOneAndUpdate", body: { _ = try $0.findOneAndUpdate(filter: [:], update: [:], session: $1) })
+        (name: "findOneAndUpdate", body: { _ = try $0.findOneAndUpdate(filter: [:], update: [:], session: $1) }),
+        (name: "drop", body: { _ = try $0.drop(session: $1) })
     ]
 
     // list of operations on MongoDatabase that take in a session
     let databaseSessionOps: [DatabaseSessionOp] = [
         (name: "runCommand", { try $0.runCommand(["isMaster": 0], session: $1) }),
         (name: "createCollection", body: { _ = try $0.createCollection("asdf", session: $1) }),
-        (name: "createCollection1", body: { _ = try $0.createCollection("asdf", withType: Document.self, session: $1) })
+        (name: "createCollection1", body: { _ = try $0.createCollection("asf", withType: Document.self, session: $1) }),
+        (name: "drop", body: { _ = try $0.drop(session: $1) })
     ]
 
     // list of operatoins on MongoClient that take in a session