fs.mitm: Implement path normalization

stratosphere/ams_mitm/source/fs_mitm/fs_path_utils.cpp

@@ -14,6 +14,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <cstring>
+#include <cstdlib>
 #include <switch.h>
 #include "fs_path_utils.hpp"
 #include "fs_results.hpp"
@@ -162,7 +163,99 @@ Result FsPathUtils::IsNormalized(bool *out, const char *path) {
     return 0;
 }
 
-Result FsPathUtils::Normalize(char *out, size_t max_out_size, const char *src, size_t *out_size) {
-    /* TODO */
-    return ResultFsNotImplemented;
+Result FsPathUtils::Normalize(char *out, size_t max_out_size, const char *src, size_t *out_len) {
+    /* Paths must start with / */
+    if (src[0] != '/') {
+        return ResultFsInvalidPathFormat;
+    }
+    
+    bool skip_next_sep = false;
+    size_t i = 0;
+    size_t len = 0;
+    
+    while (src[i] != 0) {
+        if (src[i] == '/') {
+            /* Swallow separators. */
+            while (src[++i] == '/') { }
+            if (src[i] == 0) {
+                break;
+            }
+            
+            /* Handle skip if needed */
+            if (!skip_next_sep) {
+                if (len + 1 == max_out_size) {
+                    out[len] = 0;
+                    *out_len = len;
+                    return ResultFsTooLongPath;
+                }
+                
+                out[len++] = '/';
+                
+                /* TODO: N has some weird windows support stuff here under a bool. */
+                /* Boolean is normally false though? */
+            }
+            skip_next_sep = false;
+        }
+        
+        /* See length of current dir. */
+        size_t dir_len = 0;
+        while (src[i+dir_len] != '/' && src[i+dir_len] != 0) {
+            dir_len++;
+        }
+        
+        if (FsPathUtils::IsCurrentDirectory(&src[i])) {
+            skip_next_sep = true;
+        } else if (FsPathUtils::IsParentDirectory(&src[i])) {
+            if (len == 1) {
+                return ResultFsDirectoryUnobtainable;
+            }
+            
+            /* Walk up a directory. */
+            len -= 2;
+            while (out[len] != '/') {
+                len--;
+            }
+        } else {
+            /* Copy, possibly truncating. */
+            if (len + dir_len + 1 <= max_out_size) {
+                for (size_t j = 0; j < dir_len; j++) {
+                    out[len++] = src[i+j];
+                }
+            } else {
+                const size_t copy_len = max_out_size - 1 - len;
+                for (size_t j = 0; j < copy_len; j++) {
+                    out[len++] = src[i+j];
+                }
+                out[len] = 0;
+                *out_len = len;
+                return ResultFsTooLongPath;
+            }
+        }
+        
+        i += dir_len;
+    }
+    
+    if (skip_next_sep) {
+        len--;
+    }
+    
+    if (len == 0 && max_out_size) {
+        out[len++] = '/';
+    }
+    
+    if (max_out_size < len - 1) {
+        return ResultFsTooLongPath;
+    }
+    
+    /* NULL terminate. */
+    out[len] = 0;
+    *out_len = len;
+    
+    /* Assert normalized. */
+    bool normalized = false;
+    if (R_FAILED(FsPathUtils::IsNormalized(&normalized, out)) || !normalized) {
+        std::abort();
+    }
+    
+    return 0;
 }

stratosphere/ams_mitm/source/fs_mitm/fs_path_utils.hpp

@@ -33,6 +33,14 @@ class FsPathUtils {
             return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z');
         }
         
+        static bool IsCurrentDirectory(const char *path) {
+            return path[0] == '.' && (path[1] == 0 || path[1] == '/');
+        }
+        
+        static bool IsParentDirectory(const char *path) {
+            return path[0] == '.' && path[1] == '.' && (path[2] == 0 || path[2] == '/');
+        }
+        
         static bool IsWindowsAbsolutePath(const char *path) {
             /* Nintendo uses this in path comparisons... */
             return IsWindowsDriveLetter(path[0]) && path[1] == ':';