2 files changed, 99 insertions, 57 deletions

diff --git a/src/common/file_util.cpp b/src/common/file_util.cpp
index b9e1fd1f6..13516a4a1 100644
--- a/src/common/file_util.cpp
+++ b/src/common/file_util.cpp
@@ -2,6 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <sstream>
 #include "common/assert.h"
 #include "common/common_funcs.h"
 #include "common/common_paths.h"
@@ -386,7 +387,7 @@ u64 GetSize(FILE* f) {
 bool CreateEmptyFile(const std::string& filename) {
     LOG_TRACE(Common_Filesystem, "{}", filename);
 
-    if (!FileUtil::IOFile(filename, "wb")) {
+    if (!FileUtil::IOFile(filename, "wb").IsOpen()) {
         LOG_ERROR(Common_Filesystem, "failed {}: {}", filename, GetLastErrorMsg());
         return false;
     }
@@ -750,7 +751,7 @@ size_t WriteStringToFile(bool text_file, const std::string& str, const char* fil
 size_t ReadFileToString(bool text_file, const char* filename, std::string& str) {
     IOFile file(filename, text_file ? "r" : "rb");
 
-    if (!file)
+    if (!file.IsOpen())
         return false;
 
     str.resize(static_cast<u32>(file.GetSize()));
@@ -799,6 +800,57 @@ void SplitFilename83(const std::string& filename, std::array<char, 9>& short_nam
     }
 }
 
+std::vector<std::string> SplitPathComponents(const std::string& filename) {
+    auto copy(filename);
+    std::replace(copy.begin(), copy.end(), '\\', '/');
+    std::vector<std::string> out;
+
+    std::stringstream stream(filename);
+    std::string item;
+    while (std::getline(stream, item, '/'))
+        out.push_back(std::move(item));
+
+    return out;
+}
+
+std::string GetParentPath(const std::string& path) {
+    auto out = path;
+    const auto name_bck_index = out.find_last_of('\\');
+    const auto name_fwd_index = out.find_last_of('/');
+    size_t name_index;
+    if (name_bck_index == std::string::npos || name_fwd_index == std::string::npos)
+        name_index = std::min<size_t>(name_bck_index, name_fwd_index);
+    else
+        name_index = std::max<size_t>(name_bck_index, name_fwd_index);
+
+    return out.erase(name_index);
+}
+
+std::string GetFilename(std::string path) {
+    std::replace(path.begin(), path.end(), '\\', '/');
+    auto name_index = path.find_last_of('/');
+    if (name_index == std::string::npos)
+        return "";
+    return path.substr(name_index + 1);
+}
+
+std::string GetExtensionFromFilename(const std::string& name) {
+    size_t index = name.find_last_of('.');
+    if (index == std::string::npos)
+        return "";
+
+    return name.substr(index + 1);
+}
+
+std::string RemoveTrailingSlash(const std::string& path) {
+    if (path.empty())
+        return path;
+    if (path.back() == '\\' || path.back() == '/')
+        return path.substr(0, path.size() - 1);
+
+    return path;
+}
+
 IOFile::IOFile() {}
 
 IOFile::IOFile(const std::string& filename, const char openmode[], int flags) {
@@ -820,7 +872,6 @@ IOFile& IOFile::operator=(IOFile&& other) noexcept {
 
 void IOFile::Swap(IOFile& other) noexcept {
     std::swap(m_file, other.m_file);
-    std::swap(m_good, other.m_good);
 }
 
 bool IOFile::Open(const std::string& filename, const char openmode[], int flags) {
@@ -837,16 +888,15 @@ bool IOFile::Open(const std::string& filename, const char openmode[], int flags)
     m_file = fopen(filename.c_str(), openmode);
 #endif
 
-    m_good = IsOpen();
-    return m_good;
+    return IsOpen();
 }
 
 bool IOFile::Close() {
     if (!IsOpen() || 0 != std::fclose(m_file))
-        m_good = false;
+        return false;
 
     m_file = nullptr;
-    return m_good;
+    return true;
 }
 
 u64 IOFile::GetSize() const {
@@ -856,11 +906,8 @@ u64 IOFile::GetSize() const {
     return 0;
 }
 
-bool IOFile::Seek(s64 off, int origin) {
-    if (!IsOpen() || 0 != fseeko(m_file, off, origin))
-        m_good = false;
-
-    return m_good;
+bool IOFile::Seek(s64 off, int origin) const {
+    return IsOpen() && 0 == fseeko(m_file, off, origin);
 }
 
 u64 IOFile::Tell() const {
@@ -871,26 +918,20 @@ u64 IOFile::Tell() const {
 }
 
 bool IOFile::Flush() {
-    if (!IsOpen() || 0 != std::fflush(m_file))
-        m_good = false;
-
-    return m_good;
+    return IsOpen() && 0 == std::fflush(m_file);
 }
 
 bool IOFile::Resize(u64 size) {
-    if (!IsOpen() || 0 !=
+    return IsOpen() && 0 ==
 #ifdef _WIN32
-                         // ector: _chsize sucks, not 64-bit safe
-                         // F|RES: changed to _chsize_s. i think it is 64-bit safe
-                         _chsize_s(_fileno(m_file), size)
+                           // ector: _chsize sucks, not 64-bit safe
+                           // F|RES: changed to _chsize_s. i think it is 64-bit safe
+                           _chsize_s(_fileno(m_file), size)
 #else
-                         // TODO: handle 64bit and growing
-                         ftruncate(fileno(m_file), size)
+                           // TODO: handle 64bit and growing
+                           ftruncate(fileno(m_file), size)
 #endif
-    )
-        m_good = false;
-
-    return m_good;
+        ;
 }
 
 } // namespace FileUtil
diff --git a/src/common/file_util.h b/src/common/file_util.h
index 5bc7fbf7c..9bb3c4109 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -150,6 +150,31 @@ size_t ReadFileToString(bool text_file, const char* filename, std::string& str);
 void SplitFilename83(const std::string& filename, std::array<char, 9>& short_name,
                      std::array<char, 4>& extension);
 
+// 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" }
+std::vector<std::string> SplitPathComponents(const std::string& filename);
+
+// Gets all of the text prior to the last '/' or '\' in the path.
+std::string GetParentPath(const std::string& path);
+
+// Gets the filename of the path
+std::string GetFilename(std::string path);
+
+// Gets the extension of the filename
+std::string GetExtensionFromFilename(const std::string& name);
+
+// Removes the final '/' or '\' if one exists
+std::string RemoveTrailingSlash(const std::string& path);
+
+// Creates a new vector containing indices [first, last) from the original.
+template <typename T>
+std::vector<T> SliceVector(const std::vector<T>& vector, size_t first, size_t last) {
+    if (first >= last)
+        return {};
+    last = std::min<size_t>(last, vector.size());
+    return std::vector<T>(vector.begin() + first, vector.begin() + first + last);
+}
+
 // simple wrapper for cstdlib file functions to
 // hopefully will make error checking easier
 // and make forgetting an fclose() harder
@@ -172,41 +197,27 @@ public:
     bool Close();
 
     template <typename T>
-    size_t ReadArray(T* data, size_t length) {
+    size_t ReadArray(T* data, size_t length) const {
         static_assert(std::is_trivially_copyable<T>(),
                       "Given array does not consist of trivially copyable objects");
 
-        if (!IsOpen()) {
-            m_good = false;
+        if (!IsOpen())
             return -1;
-        }
 
-        size_t items_read = std::fread(data, sizeof(T), length, m_file);
-        if (items_read != length)
-            m_good = false;
-
-        return items_read;
+        return std::fread(data, sizeof(T), length, m_file);
     }
 
     template <typename T>
     size_t WriteArray(const T* data, size_t length) {
         static_assert(std::is_trivially_copyable<T>(),
                       "Given array does not consist of trivially copyable objects");
-
-        if (!IsOpen()) {
-            m_good = false;
+        if (!IsOpen())
             return -1;
-        }
-
-        size_t items_written = std::fwrite(data, sizeof(T), length, m_file);
-        if (items_written != length)
-            m_good = false;
-
-        return items_written;
+        return std::fwrite(data, sizeof(T), length, m_file);
     }
 
     template <typename T>
-    size_t ReadBytes(T* data, size_t length) {
+    size_t ReadBytes(T* data, size_t length) const {
         static_assert(std::is_trivially_copyable<T>(), "T must be trivially copyable");
         return ReadArray(reinterpret_cast<char*>(data), length);
     }
@@ -231,15 +242,7 @@ public:
         return nullptr != m_file;
     }
 
-    // m_good is set to false when a read, write or other function fails
-    bool IsGood() const {
-        return m_good;
-    }
-    explicit operator bool() const {
-        return IsGood();
-    }
-
-    bool Seek(s64 off, int origin);
+    bool Seek(s64 off, int origin) const;
     u64 Tell() const;
     u64 GetSize() const;
     bool Resize(u64 size);
@@ -247,13 +250,11 @@ public:
 
     // clear error state
     void Clear() {
-        m_good = true;
         std::clearerr(m_file);
     }
 
 private:
     std::FILE* m_file = nullptr;
-    bool m_good = true;
 };
 
 } // namespace FileUtil