From 05f5df51f72a7a597d606a9ffb95bbd326f06880 Mon Sep 17 00:00:00 2001
From: George Hazan <ghazan@miranda.im>
Date: Thu, 31 Oct 2019 16:45:22 +0300
Subject: fix for occasional crashes in icolib

---
 src/mir_app/src/IcoLib.h   |  3 +++
 src/mir_app/src/icolib.cpp | 27 ++++++++++++++++++++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)

(limited to 'src/mir_app')

diff --git a/src/mir_app/src/IcoLib.h b/src/mir_app/src/IcoLib.h
index 9474295ac1..dd956e2162 100644
--- a/src/mir_app/src/IcoLib.h
+++ b/src/mir_app/src/IcoLib.h
@@ -24,6 +24,8 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 #pragma once
 
+#define ICOLIB_MAGIC 0xDEADBEEF
+
 #define SECTIONPARAM_MAKE(index, level, flags) MAKELONG((index)&0xFFFF, MAKEWORD(level, flags))
 #define SECTIONPARAM_INDEX(lparam) LOWORD(lparam)
 #define SECTIONPARAM_LEVEL(lparam) LOBYTE(HIWORD(lparam))
@@ -78,6 +80,7 @@ public:
 struct IcolibItem : public MZeroedObject
 {
 	char*           name;
+	DWORD           signature = ICOLIB_MAGIC;
 	SectionItem*    section;
 	int             orderID;
 	wchar_t*        description;
diff --git a/src/mir_app/src/icolib.cpp b/src/mir_app/src/icolib.cpp
index c5d86d2329..5411646a94 100644
--- a/src/mir_app/src/icolib.cpp
+++ b/src/mir_app/src/icolib.cpp
@@ -72,6 +72,22 @@ void __fastcall SafeDestroyIcon(HICON &hIcon)
 
 // Helper functions to manage Icon resources
 
+static IcolibItem *Handle2Ptr(HANDLE hIcoLib)
+{
+	IcolibItem *p = (IcolibItem *)hIcoLib;
+	if (p == nullptr)
+		return nullptr;
+
+	__try {
+		if (p->signature != ICOLIB_MAGIC)
+			p = nullptr;
+	}
+	__except (EXCEPTION_EXECUTE_HANDLER) {
+		p = nullptr;
+	}
+	return p;
+}
+
 static IconSourceFile* IconSourceFile_Get(const wchar_t *file, bool isPath)
 {
 	if (!file)
@@ -581,9 +597,10 @@ MIR_APP_DLL(void) IcoLib_RemoveIcon(const char *pszIconName)
 
 MIR_APP_DLL(void) IcoLib_RemoveIconByHandle(HANDLE hIcoLib)
 {
-	mir_cslock lck(csIconList);
+	auto *pItem = Handle2Ptr(hIcoLib);
 
-	int i = iconList.getIndex((IcolibItem*)hIcoLib);
+	mir_cslock lck(csIconList);
+	int i = iconList.getIndex(pItem);
 	if (i != -1) {
 		iconList.remove(i);
 		delete iconList[i];
@@ -655,7 +672,7 @@ HICON IconItem_GetDefaultIcon(IcolibItem *item, bool big)
 
 HICON IconItem_GetIcon(HANDLE hIcoLib, bool big)
 {
-	IcolibItem *item = (IcolibItem*)hIcoLib;
+	auto *item = Handle2Ptr(hIcoLib);
 	if (item == nullptr)
 		return nullptr;
 
@@ -724,11 +741,11 @@ MIR_APP_DLL(HANDLE) IcoLib_GetIconHandle(const char *pszIconName)
 
 MIR_APP_DLL(HICON) IcoLib_GetIconByHandle(HANDLE hItem, bool big)
 {
-	if (hItem == nullptr)
+	IcolibItem *pi = Handle2Ptr(hItem);
+	if (pi == nullptr)
 		return nullptr;
 
 	mir_cslock lck(csIconList);
-	IcolibItem *pi = (IcolibItem*)hItem;
 	if (iconList.getIndex(pi) != -1)
 		return IconItem_GetIcon(pi, big);
 
-- 
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