HLE: Revamp error handling throrough the HLE code

All service calls in the CTR OS return result codes indicating the
success or failure of the call. Previous to this commit, Citra's HLE
emulation of services and the kernel universally either ignored errors
or returned dummy -1 error codes.

This commit makes an initial effort to provide an infrastructure for
error reporting and propagation which can be use going forward to make
HLE calls accurately return errors as the original system. A few parts
of the code have been updated to use the new system where applicable.

One part of this effort is the definition of the `ResultCode` type,
which provides facilities for constructing and parsing error codes in
the structured format used by the CTR.

The `ResultVal` type builds on `ResultCode` by providing a container for
values returned by function that can report errors. It enforces that
correct error checking will be done on function returns by preventing
the use of the return value if the function returned an error code.

Currently this change is mostly internal since errors are still
suppressed on the ARM<->HLE border, as a temporary compatibility hack.
As functionality is implemented and tested this hack can be eventually
removed.

1 files changed, 17 insertions, 27 deletions

diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index e0c94f186..8d3937ce8 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -7,6 +7,7 @@
 #include <array>
 #include <string>
 #include "common/common.h"
+#include "core/hle/result.h"
 
 typedef u32 Handle;
 typedef s32 Result;
@@ -52,21 +53,19 @@ public:
     virtual Kernel::HandleType GetHandleType() const = 0;
 
     /**
-     * Synchronize kernel object
-     * @param wait Boolean wait set if current thread should wait as a result of sync operation
-     * @return Result of operation, 0 on success, otherwise error code
+     * Synchronize kernel object.
+     * @return True if the current thread should wait as a result of the sync
      */
-    virtual Result SyncRequest(bool* wait) {
+    virtual ResultVal<bool> SyncRequest() {
         ERROR_LOG(KERNEL, "(UNIMPLEMENTED)");
-        return -1;
+        return UnimplementedFunction(ErrorModule::Kernel);
     }
 
     /**
-     * Wait for kernel object to synchronize
-     * @param wait Boolean wait set if current thread should wait as a result of sync operation
-     * @return Result of operation, 0 on success, otherwise error code
+     * Wait for kernel object to synchronize.
+     * @return True if the current thread should wait as a result of the wait
      */
-    virtual Result WaitSynchronization(bool* wait) = 0;
+    virtual ResultVal<bool> WaitSynchronization() = 0;
 };
 
 class ObjectPool : NonCopyable {
@@ -80,38 +79,29 @@ public:
     static Object* CreateByIDType(int type);
 
     template <class T>
-    u32 Destroy(Handle handle) {
-        u32 error;
-        if (Get<T>(handle, error)) {
+    void Destroy(Handle handle) {
+        if (Get<T>(handle)) {
             occupied[handle - HANDLE_OFFSET] = false;
             delete pool[handle - HANDLE_OFFSET];
         }
-        return error;
     }
 
     bool IsValid(Handle handle);
 
     template <class T>
-    T* Get(Handle handle, u32& outError) {
+    T* Get(Handle handle) {
         if (handle < HANDLE_OFFSET || handle >= HANDLE_OFFSET + MAX_COUNT || !occupied[handle - HANDLE_OFFSET]) {
-            // Tekken 6 spams 0x80020001 gets wrong with no ill effects, also on the real PSP
-            if (handle != 0 && (u32)handle != 0x80020001) {
+            if (handle != 0) {
                 WARN_LOG(KERNEL, "Kernel: Bad object handle %i (%08x)", handle, handle);
             }
-            outError = 0;//T::GetMissingErrorCode();
-            return 0;
+            return nullptr;
         } else {
-            // Previously we had a dynamic_cast here, but since RTTI was disabled traditionally,
-            // it just acted as a static case and everything worked. This means that we will never
-            // see the Wrong type object error below, but we'll just have to live with that danger.
-            T* t = static_cast<T*>(pool[handle - HANDLE_OFFSET]);
-            if (t == 0 || t->GetHandleType() != T::GetStaticHandleType()) {
+            Object* t = pool[handle - HANDLE_OFFSET];
+            if (t->GetHandleType() != T::GetStaticHandleType()) {
                 WARN_LOG(KERNEL, "Kernel: Wrong object type for %i (%08x)", handle, handle);
-                outError = 0;//T::GetMissingErrorCode();
-                return 0;
+                return nullptr;
             }
-            outError = 0;//SCE_KERNEL_ERROR_OK;
-            return t;
+            return static_cast<T*>(t);
         }
     }