4 files changed, 64 insertions, 20 deletions

diff --git a/src/common/fs/path_util.cpp b/src/common/fs/path_util.cpp
index c3a81f9a9..d2f50432a 100644
--- a/src/common/fs/path_util.cpp
+++ b/src/common/fs/path_util.cpp
@@ -354,18 +354,36 @@ std::string_view RemoveTrailingSlash(std::string_view path) {
     return path;
 }
 
-std::vector<std::string> SplitPathComponents(std::string_view filename) {
-    std::string copy(filename);
-    std::replace(copy.begin(), copy.end(), '\\', '/');
-    std::vector<std::string> out;
-
-    std::stringstream stream(copy);
-    std::string item;
-    while (std::getline(stream, item, '/')) {
-        out.push_back(std::move(item));
+template <typename F>
+static void ForEachPathComponent(std::string_view filename, F&& cb) {
+    const char* component_begin = filename.data();
+    const char* const end = component_begin + filename.size();
+    for (const char* it = component_begin; it != end; ++it) {
+        const char c = *it;
+        if (c == '\\' || c == '/') {
+            if (component_begin != it) {
+                cb(std::string_view{component_begin, it});
+            }
+            component_begin = it + 1;
+        }
     }
+    if (component_begin != end) {
+        cb(std::string_view{component_begin, end});
+    }
+}
+
+std::vector<std::string_view> SplitPathComponents(std::string_view filename) {
+    std::vector<std::string_view> components;
+    ForEachPathComponent(filename, [&](auto component) { components.emplace_back(component); });
+
+    return components;
+}
+
+std::vector<std::string> SplitPathComponentsCopy(std::string_view filename) {
+    std::vector<std::string> components;
+    ForEachPathComponent(filename, [&](auto component) { components.emplace_back(component); });
 
-    return out;
+    return components;
 }
 
 std::string SanitizePath(std::string_view path_, DirectorySeparator directory_separator) {
diff --git a/src/common/fs/path_util.h b/src/common/fs/path_util.h
index 2874ea738..23c8b1359 100644
--- a/src/common/fs/path_util.h
+++ b/src/common/fs/path_util.h
@@ -289,7 +289,11 @@ enum class DirectorySeparator {
 
 // Splits the path on '/' or '\' and put the components into a vector
 // i.e. "C:\Users\Yuzu\Documents\save.bin" becomes {"C:", "Users", "Yuzu", "Documents", "save.bin" }
-[[nodiscard]] std::vector<std::string> SplitPathComponents(std::string_view filename);
+[[nodiscard]] std::vector<std::string_view> SplitPathComponents(std::string_view filename);
+
+// Splits the path on '/' or '\' and put the components into a vector
+// i.e. "C:\Users\Yuzu\Documents\save.bin" becomes {"C:", "Users", "Yuzu", "Documents", "save.bin" }
+[[nodiscard]] std::vector<std::string> SplitPathComponentsCopy(std::string_view filename);
 
 // Removes trailing slash, makes all '\\' into '/', and removes duplicate '/'. Makes '/' into '\\'
 // depending if directory_separator is BackwardSlash or PlatformDefault and running on windows
diff --git a/src/common/host_memory.cpp b/src/common/host_memory.cpp
index 4bfc64f2d..e540375b8 100644
--- a/src/common/host_memory.cpp
+++ b/src/common/host_memory.cpp
@@ -11,10 +11,6 @@
 
 #elif defined(__linux__) || defined(__FreeBSD__) // ^^^ Windows ^^^ vvv Linux vvv
 
-#ifdef ANDROID
-#include <android/sharedmem.h>
-#endif
-
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
 #endif
@@ -193,6 +189,11 @@ public:
         }
     }
 
+    bool ClearBackingRegion(size_t physical_offset, size_t length) {
+        // TODO: This does not seem to be possible on Windows.
+        return false;
+    }
+
     void EnableDirectMappedAddress() {
         // TODO
         UNREACHABLE();
@@ -442,9 +443,7 @@ public:
         }
 
         // Backing memory initialization
-#ifdef ANDROID
-        fd = ASharedMemory_create("HostMemory", backing_size);
-#elif defined(__FreeBSD__) && __FreeBSD__ < 13
+#if defined(__FreeBSD__) && __FreeBSD__ < 13
         // XXX Drop after FreeBSD 12.* reaches EOL on 2024-06-30
         fd = shm_open(SHM_ANON, O_RDWR, 0600);
 #else
@@ -455,7 +454,6 @@ public:
             throw std::bad_alloc{};
         }
 
-#ifndef ANDROID
         // Defined to extend the file with zeros
         int ret = ftruncate(fd, backing_size);
         if (ret != 0) {
@@ -463,7 +461,6 @@ public:
                          strerror(errno));
             throw std::bad_alloc{};
         }
-#endif
 
         backing_base = static_cast<u8*>(
             mmap(nullptr, backing_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
@@ -552,6 +549,19 @@ public:
         ASSERT_MSG(ret == 0, "mprotect failed: {}", strerror(errno));
     }
 
+    bool ClearBackingRegion(size_t physical_offset, size_t length) {
+#ifdef __linux__
+        // Set MADV_REMOVE on backing map to destroy it instantly.
+        // This also deletes the area from the backing file.
+        int ret = madvise(backing_base + physical_offset, length, MADV_REMOVE);
+        ASSERT_MSG(ret == 0, "madvise failed: {}", strerror(errno));
+
+        return true;
+#else
+        return false;
+#endif
+    }
+
     void EnableDirectMappedAddress() {
         virtual_base = nullptr;
     }
@@ -623,6 +633,10 @@ public:
 
     void Protect(size_t virtual_offset, size_t length, bool read, bool write, bool execute) {}
 
+    bool ClearBackingRegion(size_t physical_offset, size_t length) {
+        return false;
+    }
+
     void EnableDirectMappedAddress() {}
 
     u8* backing_base{nullptr};
@@ -698,6 +712,12 @@ void HostMemory::Protect(size_t virtual_offset, size_t length, bool read, bool w
     impl->Protect(virtual_offset + virtual_base_offset, length, read, write, execute);
 }
 
+void HostMemory::ClearBackingRegion(size_t physical_offset, size_t length, u32 fill_value) {
+    if (!impl || fill_value != 0 || !impl->ClearBackingRegion(physical_offset, length)) {
+        std::memset(backing_base + physical_offset, fill_value, length);
+    }
+}
+
 void HostMemory::EnableDirectMappedAddress() {
     if (impl) {
         impl->EnableDirectMappedAddress();
diff --git a/src/common/host_memory.h b/src/common/host_memory.h
index cebfacab2..747c5850c 100644
--- a/src/common/host_memory.h
+++ b/src/common/host_memory.h
@@ -48,6 +48,8 @@ public:
 
     void EnableDirectMappedAddress();
 
+    void ClearBackingRegion(size_t physical_offset, size_t length, u32 fill_value);
+
     [[nodiscard]] u8* BackingBasePointer() noexcept {
         return backing_base;
     }