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, 30 insertions, 21 deletions

diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index cc70cbca7..b01779f2e 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -11,10 +11,11 @@
 #include "common/thread_queue_list.h"
 
 #include "core/core.h"
-#include "core/mem_map.h"
 #include "core/hle/hle.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/thread.h"
+#include "core/hle/result.h"
+#include "core/mem_map.h"
 
 namespace Kernel {
 
@@ -38,16 +39,17 @@ public:
      * @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
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         if (status != THREADSTATUS_DORMANT) {
             Handle thread = GetCurrentThreadHandle();
             if (std::find(waiting_threads.begin(), waiting_threads.end(), thread) == waiting_threads.end()) {
                 waiting_threads.push_back(thread);
             }
             WaitCurrentThread(WAITTYPE_THREADEND, this->GetHandle());
-            *wait = true;
+            return MakeResult<bool>(true);
+        } else {
+            return MakeResult<bool>(false);
         }
-        return 0;
     }
 
     ThreadContext context;
@@ -144,9 +146,9 @@ void ChangeReadyState(Thread* t, bool ready) {
 }
 
 /// Verify that a thread has not been released from waiting
-inline bool VerifyWait(const Handle& handle, WaitType type, Handle wait_handle) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
+inline bool VerifyWait(Handle handle, WaitType type, Handle wait_handle) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    _dbg_assert_(KERNEL, thread != nullptr);
 
     if (type != thread->wait_type || wait_handle != thread->wait_handle)
         return false;
@@ -155,9 +157,9 @@ inline bool VerifyWait(const Handle& handle, WaitType type, Handle wait_handle)
 }
 
 /// Stops the current thread
-void StopThread(Handle handle, const char* reason) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
+ResultCode StopThread(Handle handle, const char* reason) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    if (thread == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     ChangeReadyState(thread, false);
     thread->status = THREADSTATUS_DORMANT;
@@ -172,6 +174,8 @@ void StopThread(Handle handle, const char* reason) {
     // Stopped threads are never waiting.
     thread->wait_type = WAITTYPE_NONE;
     thread->wait_handle = 0;
+
+    return RESULT_SUCCESS;
 }
 
 /// Changes a threads state
@@ -201,7 +205,9 @@ Handle ArbitrateHighestPriorityThread(u32 arbiter, u32 address) {
         if (!VerifyWait(handle, WAITTYPE_ARB, arbiter))
             continue;
 
-        Thread* thread = g_object_pool.GetFast<Thread>(handle);
+        Thread* thread = g_object_pool.Get<Thread>(handle);
+        if (thread == nullptr)
+            continue; // TODO(yuriks): Thread handle will hang around forever. Should clean up.
         if(thread->current_priority <= priority) {
             highest_priority_thread = handle;
             priority = thread->current_priority;
@@ -272,7 +278,7 @@ Thread* NextThread() {
     if (next == 0) {
         return nullptr;
     }
-    return Kernel::g_object_pool.GetFast<Thread>(next);
+    return Kernel::g_object_pool.Get<Thread>(next);
 }
 
 /**
@@ -289,8 +295,7 @@ void WaitCurrentThread(WaitType wait_type, Handle wait_handle) {
 
 /// Resumes a thread from waiting by marking it as "ready"
 void ResumeThreadFromWait(Handle handle) {
-    u32 error;
-    Thread* thread = Kernel::g_object_pool.Get<Thread>(handle, error);
+    Thread* thread = Kernel::g_object_pool.Get<Thread>(handle);
     if (thread) {
         thread->status &= ~THREADSTATUS_WAIT;
         if (!(thread->status & (THREADSTATUS_WAITSUSPEND | THREADSTATUS_DORMANT | THREADSTATUS_DEAD))) {
@@ -378,19 +383,23 @@ Handle CreateThread(const char* name, u32 entry_point, s32 priority, u32 arg, s3
 }
 
 /// Get the priority of the thread specified by handle
-u32 GetThreadPriority(const Handle handle) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
-    return thread->current_priority;
+ResultVal<u32> GetThreadPriority(const Handle handle) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    if (thread == nullptr) return InvalidHandle(ErrorModule::Kernel);
+
+    return MakeResult<u32>(thread->current_priority);
 }
 
 /// Set the priority of the thread specified by handle
-Result SetThreadPriority(Handle handle, s32 priority) {
+ResultCode SetThreadPriority(Handle handle, s32 priority) {
     Thread* thread = nullptr;
     if (!handle) {
         thread = GetCurrentThread(); // TODO(bunnei): Is this correct behavior?
     } else {
-        thread = g_object_pool.GetFast<Thread>(handle);
+        thread = g_object_pool.Get<Thread>(handle);
+        if (thread == nullptr) {
+            return InvalidHandle(ErrorModule::Kernel);
+        }
     }
     _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
 
@@ -417,7 +426,7 @@ Result SetThreadPriority(Handle handle, s32 priority) {
         thread_ready_queue.push_back(thread->current_priority, handle);
     }
 
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /// Sets up the primary application thread