FileSys: add PathParser

src/core/file_sys/path_parser.cpp

@@ -0,0 +1,98 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <set>
+#include "common/file_util.h"
+#include "common/string_util.h"
+#include "core/file_sys/path_parser.h"
+
+namespace FileSys {
+
+PathParser::PathParser(const Path& path) {
+    if (path.GetType() != LowPathType::Char && path.GetType() != LowPathType::Wchar) {
+        is_valid = false;
+        return;
+    }
+
+    auto path_string = path.AsString();
+    if (path_string.size() == 0 || path_string[0] != '/') {
+        is_valid = false;
+        return;
+    }
+
+    // Filter out invalid characters for the host system.
+    // Although some of these characters are valid on 3DS, they are unlikely to be used by games.
+    if (std::find_if(path_string.begin(), path_string.end(), [](char c) {
+            static const std::set<char> invalid_chars{'<', '>', '\\', '|', ':', '\"', '*', '?'};
+            return invalid_chars.find(c) != invalid_chars.end();
+        }) != path_string.end()) {
+        is_valid = false;
+        return;
+    }
+
+    Common::SplitString(path_string, '/', path_sequence);
+
+    auto begin = path_sequence.begin();
+    auto end = path_sequence.end();
+    end = std::remove_if(begin, end, [](std::string& str) { return str == "" || str == "."; });
+    path_sequence = std::vector<std::string>(begin, end);
+
+    // checks if the path is out of bounds.
+    int level = 0;
+    for (auto& node : path_sequence) {
+        if (node == "..") {
+            --level;
+            if (level < 0) {
+                is_valid = false;
+                return;
+            }
+        } else {
+            ++level;
+        }
+    }
+
+    is_valid = true;
+    is_root = level == 0;
+}
+
+PathParser::HostStatus PathParser::GetHostStatus(const std::string& mount_point) const {
+    auto path = mount_point;
+    if (!FileUtil::IsDirectory(path))
+        return InvalidMountPoint;
+    if (path_sequence.empty()) {
+        return DirectoryFound;
+    }
+
+    for (auto iter = path_sequence.begin(); iter != path_sequence.end() - 1; iter++) {
+        if (path.back() != '/')
+            path += '/';
+        path += *iter;
+
+        if (!FileUtil::Exists(path))
+            return PathNotFound;
+        if (FileUtil::IsDirectory(path))
+            continue;
+        return FileInPath;
+    }
+
+    path += "/" + path_sequence.back();
+    if (!FileUtil::Exists(path))
+        return NotFound;
+    if (FileUtil::IsDirectory(path))
+        return DirectoryFound;
+    return FileFound;
+}
+
+std::string PathParser::BuildHostPath(const std::string& mount_point) const {
+    std::string path = mount_point;
+    for (auto& node : path_sequence) {
+        if (path.back() != '/')
+            path += '/';
+        path += node;
+    }
+    return path;
+}
+
+} // namespace FileSys