LocalFileSystem: Moved away from deprecated open functions

The old open/opendir functions did not provide a route for errors and
relied on implementations manually setting errno. Updated to return
errors directly.

Author: geky

features/filesystem/FileSystem.cpp

@@ -123,6 +123,7 @@ size_t FileSystem::dir_size(fs_dir_t dir)
     return size;
 }
 
+// Internally used file wrapper that manages memory on close
 template <typename F>
 class Managed : public F {
 public:

features/filesystem/FileSystem.h

@@ -237,8 +237,6 @@ class FileSystem : public FileSystemLike {
 
 protected:
     // Hooks for FileSystemHandle
-    virtual int open(File *file, const char *path, int flags);
-    virtual int open(Dir *dir, const char *path);
     virtual int open(FileHandle **file, const char *path, int flags);
     virtual int open(DirHandle **dir, const char *path);
 };

platform/FileSystemLike.h

@@ -74,7 +74,7 @@ class FileSystemLike : public FileSystemHandle, public FileBase {
      */
     MBED_DEPRECATED_SINCE("mbed-os-5.5",
         "Replaced by `int open(FileHandle **, ...)` for propagating error codes")
-    virtual FileHandle *open(const char *path, int flags)
+    FileHandle *open(const char *path, int flags)
     {
         FileHandle *file;
         int err = open(&file, path, flags);
@@ -89,7 +89,7 @@ class FileSystemLike : public FileSystemHandle, public FileBase {
      */
     MBED_DEPRECATED_SINCE("mbed-os-5.5",
         "Replaced by `int open(DirHandle **, ...)` for propagating error codes")
-    virtual DirHandle *opendir(const char *path)
+    DirHandle *opendir(const char *path)
     {
         DirHandle *dir;
         int err = open(&dir, path);

platform/LocalFileSystem.cpp

@@ -20,6 +20,7 @@
 #include "platform/mbed_semihost_api.h"
 #include <string.h>
 #include <stdio.h>
+#include <errno.h>
 
 namespace mbed {
 
@@ -235,26 +236,28 @@ class LocalDirHandle : public DirHandle {
     }
 };
 
-FileHandle *LocalFileSystem::open(const char* name, int flags) {
+int LocalFileSystem::open(FileHandle **file, const char* name, int flags) {
     // No global state modified so function is thread safe
 
     /* reject filenames with / in them */
     for (const char *tmp = name; *tmp; tmp++) {
         if (*tmp == '/') {
-            return NULL;
+            return -EINVAL;
         }
     }
 
     int openmode = posix_to_semihost_open_flags(flags);
     if (openmode == OPEN_INVALID) {
-        return NULL;
+        return -EINVAL;
     }
 
     FILEHANDLE fh = semihost_open(name, openmode);
     if (fh == -1) {
-        return NULL;
+        return -EIO;
     }
-    return new LocalFileHandle(fh);
+
+    *file = new LocalFileHandle(fh);
+    return 0;
 }
 
 int LocalFileSystem::remove(const char *filename) {
@@ -263,10 +266,11 @@ int LocalFileSystem::remove(const char *filename) {
     return semihost_remove(filename);
 }
 
-DirHandle *LocalFileSystem::opendir(const char *name) {
+int LocalFileSystem::open(DirHandle **dir, const char *name) {
     // No global state modified so function is thread safe
 
-    return new LocalDirHandle();
+    *dir = new LocalDirHandle();
+    return 0;
 }
 
 } // namespace mbed

platform/LocalFileSystem.h

@@ -100,9 +100,9 @@ class LocalFileSystem : public FileSystemLike {
 
     }
 
-    virtual FileHandle *open(const char* name, int flags);
+    virtual int open(FileHandle **file, const char *path, int flags);
+    virtual int open(DirHandle **dir, const char *name);
     virtual int remove(const char *filename);
-    virtual DirHandle *opendir(const char *name);
 };
 
 } // namespace mbed