From dac8e20aade28443c27744ce421781be441a5bd1 Mon Sep 17 00:00:00 2001
From: sledgehammer999 <hammered999@gmail.com>
Date: Thu, 7 Aug 2014 23:05:47 +0300
Subject: [PATCH] Limit max cache to 1800MiB for 32bits compiled binaries and
 to 4GiB for other. Closes #1698.

Conflicts:
	src/preferences/advancedsettings.h
	src/preferences/preferences.cpp
---
 src/preferences/advancedsettings.h | 10 +++++++++-
 src/preferences/preferences.h      | 30 ++++++++++++++++++++++++++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/preferences/advancedsettings.h b/src/preferences/advancedsettings.h
index 17aa8c8ba..464bb5616 100644
--- a/src/preferences/advancedsettings.h
+++ b/src/preferences/advancedsettings.h
@@ -178,7 +178,15 @@ private slots:
     const Preferences pref;
     // Disk write cache
     spin_cache.setMinimum(0);
-    spin_cache.setMaximum(2048);
+    // When build as 32bit binary, set the maximum at less than 2GB to prevent crashes.
+    // These macros may not be available on compilers other than MSVC and GCC
+#if !defined(_M_X64) || !defined(__amd64__)
+    //1800MiB to leave 248MiB room to the rest of program data in RAM
+    spin_cache.setMaximum(1800);
+#else
+    // 4GiB
+    spin_cache.setMaximum(4*1024);
+#endif
     spin_cache.setValue(pref.diskCacheSize());
     updateCacheSpinSuffix(spin_cache.value());
     setRow(DISK_CACHE, tr("Disk write cache size"), &spin_cache);
diff --git a/src/preferences/preferences.h b/src/preferences/preferences.h
index 665230d84..14b7a6d66 100755
--- a/src/preferences/preferences.h
+++ b/src/preferences/preferences.h
@@ -985,14 +985,40 @@ public:
 
   uint diskCacheSize() const {
 #if LIBTORRENT_VERSION_NUM >= 1610
-    return value(QString::fromUtf8("Preferences/Downloads/DiskWriteCacheSize"), 0).toUInt();
+    uint size = value(QString::fromUtf8("Preferences/Downloads/DiskWriteCacheSize"), 0).toUInt();
+
+    // When build as 32bit binary, set the maximum at less than 2GB to prevent crashes.
+    // These macros may not be available on compilers other than MSVC and GCC
+#if !defined(_M_X64) || !defined(__amd64__)
+    //1800MiB to leave 248MiB room to the rest of program data in RAM
+    if (size > 1800)
+      size = 1800;
+#else
+    // 4GiB
+    if (size > 4*1024)
+      size = 4*1024;
+#endif
+
+    return size;
 #else
     return value(QString::fromUtf8("Preferences/Downloads/DiskWriteCacheSize"), 128).toUInt();
 #endif
   }
 
   void setDiskCacheSize(uint size) {
-    setValue(QString::fromUtf8("Preferences/Downloads/DiskWriteCacheSize"), size);
+    uint size0 = size;
+
+#if !defined(_M_X64) || !defined(__amd64__)
+    //1800MiB to leave 248MiB room to the rest of program data in RAM
+    if (size0 > 1800)
+      size0 = 1800;
+#else
+    // 4GiB
+    if (size0 > 4*1024)
+      size0 = 4*1024;
+#endif
+
+    setValue(QString::fromUtf8("Preferences/Downloads/DiskWriteCacheSize"), size0);
   }
 
 #if LIBTORRENT_VERSION_NUM >= 1610