scope Requests to an Environment object for easier cancelation

we are now scoping all file requests to an environment object. The FileSource implementation treats
this as an opaque pointer, but allows canceling all Requests that are associated with that pointer.
This is necessary to abort all file requests that originated from a particular Map object. Aborting
a file request is different from canceling a file request: A canceled request doesn't have its
callback called, while an aborted request will have its callback called with an error, indicating
that the environment is going to be shut down.

1 files changed, 10 insertions, 2 deletions

diff --git a/include/mbgl/storage/file_source.hpp b/include/mbgl/storage/file_source.hpp
index 8517d6e4a6..30e88c39f6 100644
--- a/include/mbgl/storage/file_source.hpp
+++ b/include/mbgl/storage/file_source.hpp
@@ -15,6 +15,7 @@ typedef struct uv_loop_s uv_loop_t;
 namespace mbgl {
 
 class Request;
+class Environment;
 
 class FileSource : private util::noncopyable {
 protected:
@@ -27,12 +28,19 @@ public:
 
     // These can be called from any thread. The callback will be invoked in the loop.
     // You can only cancel a request from the same thread it was created in.
-    virtual Request *request(const Resource &resource, uv_loop_t *loop, Callback callback) = 0;
+    virtual Request *request(const Resource &resource, uv_loop_t *loop, const Environment &env,
+                             Callback callback) = 0;
     virtual void cancel(Request *request) = 0;
 
     // These can be called from any thread. The callback will be invoked in an arbitrary other thread.
     // You cannot cancel these requests.
-    virtual void request(const Resource &resource, Callback callback) = 0;
+    virtual void request(const Resource &resource, const Environment &env, Callback callback) = 0;
+
+    // This can be called from any thread. All requests with the environment pointer env should be
+    // notified as errored. Note that this is /different/ from canceling requests; a canceled
+    // request's callback is never called, while an aborted request's callback is called with
+    // a error message.
+    virtual void abort(const Environment &env) = 0;
 };
 
 }