[core] Switch unordered_map with map

Change container types where number of elements expected
to be rather small.

platform/default/include/mbgl/storage/offline_database.hpp

@@ -9,10 +9,10 @@
 #include <mbgl/util/mapbox.hpp>
 #include <mbgl/util/expected.hpp>
 
-#include <unordered_map>
+#include <list>
+#include <map>
 #include <memory>
 #include <string>
-#include <list>
 
 namespace mapbox {
 namespace sqlite {
@@ -135,7 +135,7 @@ class OfflineDatabase : private util::noncopyable {
 
     std::string path;
     std::unique_ptr<mapbox::sqlite::Database> db;
-    std::unordered_map<const char *, const std::unique_ptr<mapbox::sqlite::Statement>> statements;
+    std::map<const char*, const std::unique_ptr<mapbox::sqlite::Statement>> statements;
 
     template <class T>
     T getPragma(const char *);

platform/default/include/mbgl/storage/offline_download.hpp

@@ -58,7 +58,7 @@ class OfflineDownload {
     std::unique_ptr<OfflineRegionObserver> observer;
 
     std::list<std::unique_ptr<AsyncRequest>> requests;
-    std::unordered_set<std::string> requiredSourceURLs;
+    std::set<std::string> requiredSourceURLs;
     std::deque<Resource> resourcesRemaining;
     std::list<Resource> resourcesToBeMarkedAsUsed;
     std::list<std::tuple<Resource, Response>> buffer;

platform/default/src/mbgl/storage/database_file_source.cpp

@@ -8,6 +8,8 @@
 #include <mbgl/util/constants.hpp>
 #include <mbgl/util/thread.hpp>
 
+#include <map>
+
 namespace mbgl {
 
 class DatabaseFileSourceThread {
@@ -131,7 +133,7 @@ class DatabaseFileSourceThread {
     }
 
     std::unique_ptr<OfflineDatabase> db;
-    std::unordered_map<int64_t, std::unique_ptr<OfflineDownload>> downloads;
+    std::map<int64_t, std::unique_ptr<OfflineDownload>> downloads;
     std::shared_ptr<FileSource> onlineFileSource;
 };
 

platform/default/src/mbgl/storage/main_resource_loader.cpp

@@ -8,6 +8,7 @@
 #include <mbgl/util/stopwatch.hpp>
 
 #include <cassert>
+#include <map>
 
 namespace mbgl {
 
@@ -170,7 +171,7 @@ class MainResourceLoader::Impl {
     const std::shared_ptr<FileSource> onlineFileSource;
     const bool supportsCacheOnlyRequests_;
     std::unique_ptr<Actor<ResourceLoaderRequestor>> requestor;
-    std::unordered_map<AsyncRequest*, std::unique_ptr<AsyncRequest>> tasks;
+    std::map<AsyncRequest*, std::unique_ptr<AsyncRequest>> tasks;
 };
 
 ResourceLoaderRequestor::ResourceLoaderRequestor(MainResourceLoader::Impl& impl_) : impl(impl_) {}

platform/default/src/mbgl/storage/online_file_source.cpp

@@ -23,8 +23,6 @@
 #include <cassert>
 #include <list>
 #include <map>
-#include <unordered_map>
-#include <unordered_set>
 
 namespace mbgl {
 
@@ -157,7 +155,7 @@ class OnlineFileSourceThread {
         auto request = pendingRequests.pop();
 
         if (request) {
-            activateRequest(*request);
+            activateRequest(request);
         }
     }
 
@@ -249,9 +247,9 @@ class OnlineFileSourceThread {
             }
         }
 
-        optional<OnlineFileRequest*> pop() {
+        OnlineFileRequest* pop() {
             if (queue.empty()) {
-                return optional<OnlineFileRequest*>();
+                return nullptr;
             }
 
             if (queue.begin() == firstLowPriorityRequest) {
@@ -260,7 +258,7 @@ class OnlineFileSourceThread {
 
             OnlineFileRequest* next = queue.front();
             queue.pop_front();
-            return optional<OnlineFileRequest*>(next);
+            return next;
         }
 
         bool contains(OnlineFileRequest* request) const {
@@ -282,11 +280,11 @@ class OnlineFileSourceThread {
      * Requests in any state are in `allRequests`. Requests in the pending state are in
      * `pendingRequests`. Requests in the active state are in `activeRequests`.
      */
-    std::unordered_set<OnlineFileRequest*> allRequests;
+    std::set<OnlineFileRequest*> allRequests;
 
     PendingRequests pendingRequests;
 
-    std::unordered_set<OnlineFileRequest*> activeRequests;
+    std::set<OnlineFileRequest*> activeRequests;
 
     bool online = true;
     uint32_t maximumConcurrentRequests;