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, 65 insertions, 82 deletions

diff --git a/src/core/hle/kernel/archive.cpp b/src/core/hle/kernel/archive.cpp
index 900f484c7..e11dddc84 100644
--- a/src/core/hle/kernel/archive.cpp
+++ b/src/core/hle/kernel/archive.cpp
@@ -9,8 +9,9 @@
 #include "core/file_sys/archive.h"
 #include "core/file_sys/archive_sdmc.h"
 #include "core/file_sys/directory.h"
-#include "core/hle/service/service.h"
 #include "core/hle/kernel/archive.h"
+#include "core/hle/result.h"
+#include "core/hle/service/service.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Kernel namespace
@@ -56,7 +57,7 @@ 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 SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
 
@@ -106,11 +107,11 @@ public:
         default:
         {
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            return -1;
+            return UnimplementedFunction(ErrorModule::FS);
         }
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -118,10 +119,10 @@ 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 {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -141,7 +142,7 @@ 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 SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
         switch (cmd) {
@@ -183,7 +184,8 @@ public:
         case FileCommand::SetSize:
         {
             u64 size = cmd_buff[1] | ((u64)cmd_buff[2] << 32);
-            DEBUG_LOG(KERNEL, "SetSize %s %s size=%llu", GetTypeName().c_str(), GetName().c_str(), size);
+            DEBUG_LOG(KERNEL, "SetSize %s %s size=%llu",
+                    GetTypeName().c_str(), GetName().c_str(), size);
             backend->SetSize(size);
             break;
         }
@@ -198,11 +200,12 @@ public:
         // Unknown command...
         default:
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            cmd_buff[1] = -1; // TODO(Link Mauve): use the correct error code for that.
-            return -1;
+            ResultCode error = UnimplementedFunction(ErrorModule::FS);
+            cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
+            return error;
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -210,10 +213,10 @@ 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 {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -233,7 +236,7 @@ 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 SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         DirectoryCommand cmd = static_cast<DirectoryCommand>(cmd_buff[0]);
         switch (cmd) {
@@ -243,8 +246,9 @@ public:
         {
             u32 count = cmd_buff[1];
             u32 address = cmd_buff[3];
-            FileSys::Entry* entries = reinterpret_cast<FileSys::Entry*>(Memory::GetPointer(address));
-            DEBUG_LOG(KERNEL, "Read %s %s: count=%d", GetTypeName().c_str(), GetName().c_str(), count);
+            auto entries = reinterpret_cast<FileSys::Entry*>(Memory::GetPointer(address));
+            DEBUG_LOG(KERNEL, "Read %s %s: count=%d",
+                    GetTypeName().c_str(), GetName().c_str(), count);
 
             // Number of entries actually read
             cmd_buff[2] = backend->Read(count, entries);
@@ -261,11 +265,12 @@ public:
         // Unknown command...
         default:
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            cmd_buff[1] = -1; // TODO(Link Mauve): use the correct error code for that.
-            return -1;
+            ResultCode error = UnimplementedFunction(ErrorModule::FS);
+            cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
+            return error;
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -273,10 +278,10 @@ 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 {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -284,89 +289,59 @@ public:
 
 std::map<FileSys::Archive::IdCode, Handle> g_archive_map; ///< Map of file archives by IdCode
 
-/**
- * Opens an archive
- * @param id_code IdCode of the archive to open
- * @return Handle to archive if it exists, otherwise a null handle (0)
- */
-Handle OpenArchive(FileSys::Archive::IdCode id_code) {
+ResultVal<Handle> OpenArchive(FileSys::Archive::IdCode id_code) {
     auto itr = g_archive_map.find(id_code);
     if (itr == g_archive_map.end()) {
-        return 0;
+        return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
+                ErrorSummary::NotFound, ErrorLevel::Permanent);
     }
-    return itr->second;
+
+    return MakeResult<Handle>(itr->second);
 }
 
-/**
- * Closes an archive
- * @param id_code IdCode of the archive to open
- * @return Result of operation, 0 on success, otherwise error code
- */
-Result CloseArchive(FileSys::Archive::IdCode id_code) {
+ResultCode CloseArchive(FileSys::Archive::IdCode id_code) {
     auto itr = g_archive_map.find(id_code);
     if (itr == g_archive_map.end()) {
         ERROR_LOG(KERNEL, "Cannot close archive %d, does not exist!", (int)id_code);
-        return -1;
+        return InvalidHandle(ErrorModule::FS);
     }
 
     INFO_LOG(KERNEL, "Closed archive %d", (int) id_code);
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
  * Mounts an archive
  * @param archive Pointer to the archive to mount
- * @return Result of operation, 0 on success, otherwise error code
+ * @return Result of operation
  */
-Result MountArchive(Archive* archive) {
+ResultCode MountArchive(Archive* archive) {
     FileSys::Archive::IdCode id_code = archive->backend->GetIdCode();
-    if (0 != OpenArchive(id_code)) {
+    ResultVal<Handle> archive_handle = OpenArchive(id_code);
+    if (archive_handle.Succeeded()) {
         ERROR_LOG(KERNEL, "Cannot mount two archives with the same ID code! (%d)", (int) id_code);
-        return -1;
+        return archive_handle.Code();
     }
     g_archive_map[id_code] = archive->GetHandle();
     INFO_LOG(KERNEL, "Mounted archive %s", archive->GetName().c_str());
-    return 0;
+    return RESULT_SUCCESS;
 }
 
-/**
- * Creates an Archive
- * @param handle Handle to newly created archive object
- * @param backend File system backend interface to the archive
- * @param name Optional name of Archive
- * @return Newly created Archive object
- */
-Archive* CreateArchive(Handle& handle, FileSys::Archive* backend, const std::string& name) {
+ResultCode CreateArchive(FileSys::Archive* backend, const std::string& name) {
     Archive* archive = new Archive;
-    handle = Kernel::g_object_pool.Create(archive);
+    Handle handle = Kernel::g_object_pool.Create(archive);
     archive->name = name;
     archive->backend = backend;
 
-    MountArchive(archive);
-
-    return archive;
-}
-
-/**
- * Creates an Archive
- * @param backend File system backend interface to the archive
- * @param name Optional name of Archive
- * @return Handle to newly created Archive object
- */
-Handle CreateArchive(FileSys::Archive* backend, const std::string& name) {
-    Handle handle;
-    CreateArchive(handle, backend, name);
-    return handle;
+    ResultCode result = MountArchive(archive);
+    if (result.IsError()) {
+        return result;
+    }
+    
+    return RESULT_SUCCESS;
 }
 
-/**
- * Open a File from an Archive
- * @param archive_handle Handle to an open Archive object
- * @param path Path to the File inside of the Archive
- * @param mode Mode under which to open the File
- * @return Opened File object
- */
-Handle OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode) {
+ResultVal<Handle> OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode) {
     // TODO(bunnei): Binary type files get a raw file pointer to the archive. Currently, we create
     // the archive file handles at app loading, and then keep them persistent throughout execution.
     // Archives file handles are just reused and not actually freed until emulation shut down.
@@ -376,19 +351,24 @@ Handle OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, con
         // design. While the functionally of this is OK, our implementation decision to separate
         // normal files from archive file pointers is very likely wrong.
         // See https://github.com/citra-emu/citra/issues/205
-        return archive_handle;
+        return MakeResult<Handle>(archive_handle);
 
     File* file = new File;
     Handle handle = Kernel::g_object_pool.Create(file);
 
-    Archive* archive = Kernel::g_object_pool.GetFast<Archive>(archive_handle);
+    Archive* archive = Kernel::g_object_pool.Get<Archive>(archive_handle);
+    if (archive == nullptr) {
+        return InvalidHandle(ErrorModule::FS);
+    }
     file->path = path;
     file->backend = archive->backend->OpenFile(path, mode);
 
-    if (!file->backend)
-        return 0;
+    if (!file->backend) {
+        return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
+                ErrorSummary::NotFound, ErrorLevel::Permanent);
+    }
 
-    return handle;
+    return MakeResult<Handle>(handle);
 }
 
 /**
@@ -442,15 +422,18 @@ Result CreateDirectoryFromArchive(Handle archive_handle, const FileSys::Path& pa
  * @param path Path to the Directory inside of the Archive
  * @return Opened Directory object
  */
-Handle OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path) {
+ResultVal<Handle> OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path) {
     Directory* directory = new Directory;
     Handle handle = Kernel::g_object_pool.Create(directory);
 
-    Archive* archive = Kernel::g_object_pool.GetFast<Archive>(archive_handle);
+    Archive* archive = Kernel::g_object_pool.Get<Archive>(archive_handle);
+    if (archive == nullptr) {
+        return InvalidHandle(ErrorModule::FS);
+    }
     directory->path = path;
     directory->backend = archive->backend->OpenDirectory(path);
 
-    return handle;
+    return MakeResult<Handle>(handle);
 }
 
 /// Initialize archives