Check for all file errors in demo player, show demo error popup

Handle the return values of all uses of the `io_read`, `io_skip` and `io_tell` functions in `CDemoPlayer`, to handle truncated demo files and other unexpected file reading and seeking errors during demo playback.

Show more detailed error message popups when demos cannot be loaded due to errors and when demo playback is stopped unexpectedly due to errors. Previously, only a generic message "Error loading demo" was shown when loading failed and no error message was shown when demo playback is stopped due to errors.

src/engine/client/client.cpp

@@ -609,6 +609,9 @@ void CClient::Connect(const char *pAddress, const char *pPassword)
 
 void CClient::DisconnectWithReason(const char *pReason)
 {
+	if(pReason != nullptr && pReason[0] == '\0')
+		pReason = nullptr;
+
 	char aBuf[512];
 	str_format(aBuf, sizeof(aBuf), "disconnecting. reason='%s'", pReason ? pReason : "unknown");
 	m_pConsole->Print(IConsole::OUTPUT_LEVEL_STANDARD, "client", aBuf, gs_ClientNetworkPrintColor);
@@ -2437,7 +2440,13 @@ void CClient::Update()
 		else
 		{
 			// disconnect on error
-			Disconnect();
+			DisconnectWithReason(m_DemoPlayer.ErrorMessage());
+			if(m_DemoPlayer.ErrorMessage()[0] != '\0')
+			{
+				SWarning Warning(Localize("Error playing demo"), m_DemoPlayer.ErrorMessage());
+				Warning.m_AutoHide = false;
+				m_vWarnings.emplace_back(Warning);
+			}
 		}
 	}
 	else if(State() == IClient::STATE_ONLINE)
@@ -3581,27 +3590,23 @@ void CClient::DemoSlice(const char *pDstPath, CLIENTFUNC_FILTER pfnFilter, void
 {
 	if(m_DemoPlayer.IsPlaying())
 	{
-		const char *pDemoFileName = m_DemoPlayer.GetDemoFileName();
-		m_DemoEditor.Slice(pDemoFileName, pDstPath, g_Config.m_ClDemoSliceBegin, g_Config.m_ClDemoSliceEnd, pfnFilter, pUser);
+		m_DemoEditor.Slice(m_DemoPlayer.Filename(), pDstPath, g_Config.m_ClDemoSliceBegin, g_Config.m_ClDemoSliceEnd, pfnFilter, pUser);
 	}
 }
 
 const char *CClient::DemoPlayer_Play(const char *pFilename, int StorageType)
 {
-	IOHANDLE File = Storage()->OpenFile(pFilename, IOFLAG_READ, StorageType);
-	if(!File)
-		return "error opening demo file";
-
-	io_close(File);
+	// Don't disconnect unless the file exists (only for play command)
+	if(!Storage()->FileExists(pFilename, StorageType))
+		return "No demo with this filename exists";
 
 	Disconnect();
 	m_aNetClient[CONN_MAIN].ResetErrorString();
 
 	// try to start playback
 	m_DemoPlayer.SetListener(this);
-
 	if(m_DemoPlayer.Load(Storage(), m_pConsole, pFilename, StorageType))
-		return "error loading demo";
+		return m_DemoPlayer.ErrorMessage();
 
 	// load map
 	const CMapInfo *pMapInfo = m_DemoPlayer.GetMapInfo();
@@ -3669,8 +3674,7 @@ const char *CClient::DemoPlayer_Render(const char *pFilename, int StorageType, c
 	{
 		m_DemoPlayer.Pause();
 	}
-	//m_pConsole->Print(IConsole::OUTPUT_LEVEL_DEBUG, "demo_recorder", "demo eof");
-	return 0;
+	return nullptr;
 }
 #endif
 

src/engine/demo.h

@@ -58,8 +58,8 @@ struct CMapInfo
 {
 	char m_aName[MAX_MAP_LENGTH];
 	SHA256_DIGEST m_Sha256;
-	int m_Crc;
-	int m_Size;
+	unsigned m_Crc;
+	unsigned m_Size;
 };
 
 class IDemoPlayer : public IInterface
@@ -100,7 +100,7 @@ class IDemoPlayer : public IInterface
 	virtual bool IsPlaying() const = 0;
 	virtual const CInfo *BaseInfo() const = 0;
 	virtual void GetDemoName(char *pBuffer, size_t BufferSize) const = 0;
-	virtual bool GetDemoInfo(class IStorage *pStorage, const char *pFilename, int StorageType, CDemoHeader *pDemoHeader, CTimelineMarkers *pTimelineMarkers, CMapInfo *pMapInfo) const = 0;
+	virtual bool GetDemoInfo(class IStorage *pStorage, class IConsole *pConsole, const char *pFilename, int StorageType, CDemoHeader *pDemoHeader, CTimelineMarkers *pTimelineMarkers, CMapInfo *pMapInfo, IOHANDLE *pFile = nullptr, char *pErrorMessage = nullptr, size_t ErrorMessageSize = 0) const = 0;
 };
 
 class IDemoRecorder : public IInterface