Measure free disk space to size block count.

CMakeLists.txt

@@ -923,6 +923,8 @@ add_library(native STATIC
 	ext/native/file/fd_util.h
 	ext/native/file/file_util.cpp
 	ext/native/file/file_util.h
+	ext/native/file/free.cpp
+	ext/native/file/free.h
 	ext/native/file/ini_file.cpp
 	ext/native/file/ini_file.h
 	ext/native/file/path.cpp

Core/FileLoaders/DiskCachingFileLoader.cpp

@@ -18,11 +18,13 @@
 #include <algorithm>
 #include <string.h>
 #include "file/file_util.h"
+#include "file/free.h"
 #include "Common/FileUtil.h"
 #include "Core/FileLoaders/DiskCachingFileLoader.h"
 #include "Core/System.h"
 
 static const char *CACHEFILE_MAGIC = "ppssppDC";
+static const s64 SAFETY_FREE_DISK_SPACE = 768 * 1024 * 1024; // 768 MB
 
 std::string DiskCachingFileLoaderCache::cacheDir_;
 
@@ -534,7 +536,30 @@ void DiskCachingFileLoaderCache::CreateCacheFile(const std::string &path) {
 	}
 }
 
-u32 DiskCachingFileLoaderCache::DetermineMaxBlocks() {
-	// TODO (don't forget to clamp UPPER)
-	return 4096;
+u64 DiskCachingFileLoaderCache::FreeDiskSpace() {
+	std::string dir = cacheDir_;
+	if (dir.empty()) {
+		dir = GetSysDirectory(DIRECTORY_CACHE);
+	}
+
+	uint64_t result = 0;
+	if (free_disk_space(dir, result)) {
+		return result;
+	}
+
+	// We can't know for sure how much is free, so we have to assume none.
+	return 0;
+}
+
+u32 DiskCachingFileLoaderCache::DetermineMaxBlocks() {
+	const s64 freeBytes = FreeDiskSpace();
+	// We want to leave them some room for other stuff.
+	const u64 availBytes = std::max(0LL, freeBytes - SAFETY_FREE_DISK_SPACE);
+	const u64 freeBlocks = availBytes / (u64)DEFAULT_BLOCK_SIZE;
+
+	if (freeBlocks > MAX_BLOCKS_UPPER_BOUND) {
+		return MAX_BLOCKS_UPPER_BOUND;
+	}
+	// Might be lower than LOWER_BOUND, but that's okay.  It means not enough space.
+	return freeBlocks;
 }

Core/FileLoaders/DiskCachingFileLoader.h

@@ -104,6 +104,7 @@ private:
 	void LoadCacheIndex();
 	void CreateCacheFile(const std::string &path);
 
+	u64 FreeDiskSpace();
 	u32 DetermineMaxBlocks();
 
 	// File format:

Core/FileSystems/DirectoryFileSystem.cpp

@@ -16,6 +16,7 @@
 // https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
 
 #include <limits>
+#include "file/free.h"
 #include "file/zip_read.h"
 #include "i18n/i18n.h"
 #include "util/text/utf8.h"
@@ -798,35 +799,18 @@ std::vector<PSPFileInfo> DirectoryFileSystem::GetDirListing(std::string path) {
 }
 
 u64 DirectoryFileSystem::FreeSpace(const std::string &path) {
-#ifdef _WIN32
-	const std::wstring w32path = ConvertUTF8ToWString(GetLocalPath(path));
-	ULARGE_INTEGER free;
-	if (GetDiskFreeSpaceExW(w32path.c_str(), &free, nullptr, nullptr))
-		return free.QuadPart;
-#elif defined(__SYMBIAN32__)
-	QSystemStorageInfo storageInfo;
-	return (u64)storageInfo.availableDiskSpace("E");
-#else
-	std::string localPath = GetLocalPath(path);
-	struct statvfs diskstat;
-	int res = statvfs(localPath.c_str(), &diskstat);
+	uint64_t result = 0;
+	if (free_disk_space(GetLocalPath(path), result)) {
+		return result;
+	}
 
 #if HOST_IS_CASE_SENSITIVE
 	std::string fixedCase = path;
-	if (res != 0 && FixPathCase(basePath, fixedCase, FPC_FILE_MUST_EXIST)) {
+	if (FixPathCase(basePath, fixedCase, FPC_FILE_MUST_EXIST)) {
 		// May have failed due to case sensitivity, try again.
-		localPath = GetLocalPath(fixedCase);
-		res = statvfs(localPath.c_str(), &diskstat);
-	}
-#endif
-
-	if (res == 0) {
-#ifndef ANDROID
-		if (diskstat.f_flag & ST_RDONLY) {
-			return 0;
+		if (free_disk_space(GetLocalPath(fixedCase), result)) {
+			return result;
 		}
-#endif
-		return (u64)diskstat.f_bavail * (u64)diskstat.f_frsize;
 	}
 #endif
 

ext/native/Android.mk

@@ -41,6 +41,7 @@ LOCAL_SRC_FILES :=\
     file/fd_util.cpp \
     file/chunk_file.cpp \
     file/file_util.cpp \
+    file/free.cpp \
     file/path.cpp \
     file/ini_file.cpp \
     file/zip_read.cpp \

ext/native/file/CMakeLists.txt

@@ -1,7 +1,8 @@
 set(SRCS
   chunk_file.cpp
   zip_read.cpp
-  file_util.cpp)
+  file_util.cpp
+  free.cpp)
 
 set(SRCS ${SRCS})
 

ext/native/file/free.cpp

@@ -0,0 +1,56 @@
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#include <sys/stat.h>
+#else
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#if defined(ANDROID)
+#include <sys/types.h>
+#include <sys/vfs.h>
+#define statvfs statfs
+#elif defined(__SYMBIAN32__)
+#include <mw/QSystemStorageInfo>
+QTM_USE_NAMESPACE
+#else
+#include <sys/statvfs.h>
+#endif
+#include <ctype.h>
+#include <fcntl.h>
+#endif
+
+#include "base/basictypes.h"
+#include "util/text/utf8.h"
+
+bool free_disk_space(const std::string &dir, uint64_t &space) {
+#ifdef _WIN32
+	const std::wstring w32path = ConvertUTF8ToWString(dir);
+	ULARGE_INTEGER free;
+	if (GetDiskFreeSpaceExW(w32path.c_str(), &free, nullptr, nullptr)) {
+		space = free.QuadPart;
+		return true;
+	}
+#elif defined(__SYMBIAN32__)
+	QSystemStorageInfo storageInfo;
+	space = (uint64_t)storageInfo.availableDiskSpace("E");
+	return true;
+#else
+	struct statvfs diskstat;
+	int res = statvfs(dir.c_str(), &diskstat);
+
+	if (res == 0) {
+#ifndef ANDROID
+		if (diskstat.f_flag & ST_RDONLY) {
+			space = 0;
+			return true;
+		}
+#endif
+		space = (uint64_t)diskstat.f_bavail * (uint64_t)diskstat.f_frsize;
+		return true;
+	}
+#endif
+
+	// We can't know how much is free.
+	return false;
+}

ext/native/file/free.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <string>
+#include "base/basictypes.h"
+
+bool free_disk_space(const std::string &dir, uint64_t &space);

ext/native/native.vcxproj

@@ -226,6 +226,7 @@
     <ClInclude Include="file\ini_file.h" />
     <ClInclude Include="file\vfs.h" />
     <ClInclude Include="file\zip_read.h" />
+    <ClInclude Include="file\free.h" />
     <ClInclude Include="gfx\gl_common.h" />
     <ClInclude Include="gfx\gl_debug_log.h" />
     <ClInclude Include="gfx\gl_lost_manager.h" />
@@ -680,6 +681,7 @@
     <ClCompile Include="file\path.cpp" />
     <ClCompile Include="file\ini_file.cpp" />
     <ClCompile Include="file\zip_read.cpp" />
+    <ClCompile Include="file\free.cpp" />
     <ClCompile Include="gfx\gl_debug_log.cpp" />
     <ClCompile Include="gfx\gl_lost_manager.cpp" />
     <ClCompile Include="gfx\texture_atlas.cpp" />

ext/native/native.vcxproj.filters

@@ -302,6 +302,9 @@
     <ClInclude Include="input\keycodes.h">
       <Filter>input</Filter>
     </ClInclude>
+    <ClInclude Include="file\free.h">
+      <Filter>file</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="gfx\gl_debug_log.cpp">
@@ -736,6 +739,9 @@
     <ClCompile Include="base\QtMain.cpp">
       <Filter>base</Filter>
     </ClCompile>
+    <ClCompile Include="file\free.cpp">
+      <Filter>file</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <Filter Include="gfx">