[ 1560785 ] wxFileName::IsReadable/Writable/Executable

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41638 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/filename.tex

@@ -93,7 +93,15 @@ class are \helpref{GetVolumeSeparator}{wxfilenamegetvolumeseparator},\rtfsp
 
 \membersection{File name construction}\label{filenameconstruction}
 
-TODO.
+You can initialize a wxFileName instance using one of the following functions:
+
+\helpref{wxFileName constructors}{wxfilenamewxfilename}\\
+\helpref{Assign}{wxfilenameassign}\\
+\helpref{AssignCwd}{wxfilenameassigncwd}\\
+\helpref{AssignDir}{wxfilenameassigndir}\\
+\helpref{AssignHomeDir}{wxfilenameassignhomedir}\\
+\helpref{AssignHomeTempFileName}{wxfilenameassigntempfilename}\\
+\helpref{operator $=$}{wxfilenameoperatorassign}
 
 
 \membersection{File tests}\label{filetests}
@@ -105,7 +113,15 @@ with such name exists and \helpref{DirExists}{wxfilenamedirexists} can be used
 to test for directory existence.
 
 File names should be compared using \helpref{SameAs}{wxfilenamesameas} method
-or \helpref{$==$}{wxfilenameoperatorequal}.
+or \helpref{operator $==$}{wxfilenameoperatorequal}.
+
+For testing basic access modes, you can use:
+
+\helpref{IsDirWritable}{wxfilenameisdirwritable}\\
+\helpref{IsDirReadable}{wxfilenameisdirreadable}\\
+\helpref{IsFileWritable}{wxfilenameisfilewritable}\\
+\helpref{IsFileReadable}{wxfilenameisfilereadable}\\
+\helpref{IsFileExecutable}{wxfilenameisfileexecutable}
 
 
 \membersection{File name components}\label{filenamecomponents}
@@ -619,6 +635,56 @@ Returns {\tt true} if this filename is absolute.
 Returns {\tt true} if the file names of this type are case-sensitive.
 
 
+\membersection{wxFileName::IsDirReadable}\label{wxfilenameisdirreadable}
+
+\constfunc{bool}{IsDirReadable}{\void}
+
+\func{static bool}{IsDirReadable}{\param{const wxString\& }{dir}}
+
+Returns {\tt true} if the directory component of this instance (or given \arg{dir})
+is an existing directory and this process has read permissions on it.
+Read permissions on a directory mean that you can list the directory contents but it
+doesn't imply that you have read permissions on the files contained.
+
+
+\membersection{wxFileName::IsDirWritable}\label{wxfilenameisdirwritable}
+
+\constfunc{bool}{IsDirWritable}{\void}
+
+\func{static bool}{IsDirWritable}{\param{const wxString\& }{dir}}
+
+Returns {\tt true} if the directory component of this instance (or given \arg{dir})
+is an existing directory and this process has write permissions on it.
+Write permissions on a directory mean that you can create new files in the directory.
+
+
+\membersection{wxFileName::IsFileExecutable}\label{wxfilenameisfileexecutable}
+
+\constfunc{bool}{IsFileExecutable}{\void}
+
+\func{static bool}{IsFileExecutable}{\param{const wxString\& }{file}}
+
+Returns {\tt true} if a file with this name exists and if this process has execute permissions on it.
+
+
+\membersection{wxFileName::IsFileReadable}\label{wxfilenameisfilereadable}
+
+\constfunc{bool}{IsFileReadable}{\void}
+
+\func{static bool}{IsFileReadable}{\param{const wxString\& }{file}}
+
+Returns {\tt true} if a file with this name exists and if this process has read permissions on it.
+
+
+\membersection{wxFileName::IsFileWritable}\label{wxfilenameisfilewritable}
+
+\constfunc{bool}{IsFileWritable}{\void}
+
+\func{static bool}{IsFileWritable}{\param{const wxString\& }{file}}
+
+Returns {\tt true} if a file with this name exists and if this process has write permissions on it.
+
+
 \membersection{wxFileName::IsOk}\label{wxfilenameisok}
 
 \constfunc{bool}{IsOk}{\void}

include/wx/filefn.h

@@ -472,6 +472,11 @@ inline bool wxPathExists(const wxChar *pszPathName)
 }
 #endif //WXWIN_COMPATIBILITY_2_6
 
+// permissions; these functions work both on files and directories:
+WXDLLIMPEXP_BASE bool wxIsWritable(const wxString &path);
+WXDLLIMPEXP_BASE bool wxIsReadable(const wxString &path);
+WXDLLIMPEXP_BASE bool wxIsExecutable(const wxString &path);
+
 // ----------------------------------------------------------------------------
 // separators in file names
 // ----------------------------------------------------------------------------

include/wx/filename.h

@@ -19,9 +19,7 @@
     2. more file operations:
         a) chmod()
         b) [acm]time() - get and set
-        c) file permissions with readable accessors for most common bits
+        c) rename()?
-           such as IsReadable() &c
-        d) rename()?
     3. SameFileAs() function to compare inodes under Unix
  */
 
@@ -86,6 +84,7 @@ enum
 extern wxULongLong wxInvalidSize;
 
 
+
 // ----------------------------------------------------------------------------
 // wxFileName: encapsulates a file path
 // ----------------------------------------------------------------------------
@@ -193,7 +192,28 @@ public:
     bool DirExists() const;
     static bool DirExists( const wxString &dir );
 
-        // VZ: also need: IsDirWritable(), IsFileExecutable() &c (TODO)
+        // checks on most common flags for files/directories;
+        // more platform-specific features (like e.g. Unix permissions) are not
+        // available in wxFileName
+
+    bool IsDirWritable() const { return wxIsWritable(GetPath()); }
+    static bool IsDirWritable(const wxString &path) { return wxDirExists(path) && wxIsWritable(path); }
+
+    bool IsDirReadable() const { return wxIsReadable(GetPath()); }
+    static bool IsDirReadable(const wxString &path) { return wxDirExists(path) && wxIsReadable(path); }
+
+    // NOTE: IsDirExecutable() is not present because the meaning of "executable"
+    //       directory is very platform-dependent and also not so useful
+
+    bool IsFileWritable() const { return wxIsWritable(GetFullPath()); }
+    static bool IsFileWritable(const wxString &path) { return wxFileExists(path) && wxIsWritable(path); }
+
+    bool IsFileReadable() const { return wxIsReadable(GetFullPath()); }
+    static bool IsFileReadable(const wxString &path) { return wxFileExists(path) && wxIsReadable(path); }
+
+    bool IsFileExecutable() const { return wxIsExecutable(GetFullPath()); }
+    static bool IsFileExecutable(const wxString &path) { return wxFileExists(path) && wxIsExecutable(path); }
+
 
     // time functions
 #if wxUSE_DATETIME

src/common/filefn.cpp

@@ -1759,6 +1759,79 @@ int WXDLLEXPORT wxParseCommonDialogsFilter(const wxString& filterStr,
     return filters.GetCount();
 }
 
+#if defined( __WINDOWS__ )
+bool wxCheckGenericPermission(const wxString &path, DWORD access)
+{
+    // quoting the MSDN: "To obtain a handle to a directory, call the
+    // CreateFile function with the FILE_FLAG_BACKUP_SEMANTICS flag"
+    wxWinVersion ver = wxGetWinVersion();
+    bool isdir = wxDirExists(path);
+    if (isdir && (ver == wxWinVersion_95 || ver == wxWinVersion_98 || ver == wxWinVersion_ME))
+    {
+        // however Win95/98/ME do not support FILE_FLAG_BACKUP_SEMANTICS...
+        if (access == GENERIC_READ)
+        {
+            WIN32_FILE_ATTRIBUTE_DATA data;
+            if (GetFileAttributesEx(path.c_str(), GetFileExInfoStandard, &data) == 0)
+                return false;        // cannot query attributes
+            return (data.dwFileAttributes & FILE_ATTRIBUTE_READONLY) == 0;
+        }
+
+        // FIXME: is it true that directories are always writable & executable on Win9X family ?
+        return true;
+    }
+    else
+    {
+        HANDLE h = CreateFile(path.c_str(), access,
+                              FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+                              OPEN_EXISTING, isdir ? FILE_FLAG_BACKUP_SEMANTICS : 0, NULL);
+        if (h != INVALID_HANDLE_VALUE)
+            CloseHandle(h);
+
+        return h != INVALID_HANDLE_VALUE;
+    }
+}
+#endif
+
+bool wxIsWritable(const wxString &path)
+{
+#if defined( __UNIX__ )
+    // access() will take in count also symbolic links
+    return access(wxConvFile.cWX2MB(path), W_OK) == 0;
+#elif defined( __WINDOWS__ )
+    return wxCheckGenericPermission(path, GENERIC_WRITE);
+#else
+    // TODO
+    return false;
+#endif
+}
+
+bool wxIsReadable(const wxString &path)
+{
+#if defined( __UNIX__ )
+    // access() will take in count also symbolic links
+    return access(wxConvFile.cWX2MB(path), R_OK) == 0;
+#elif defined( __WINDOWS__ )
+    return wxCheckGenericPermission(path, GENERIC_READ);
+#else
+    // TODO
+    return false;
+#endif
+}
+
+bool wxIsExecutable(const wxString &path)
+{
+#if defined( __UNIX__ )
+    // access() will take in count also symbolic links
+    return access(wxConvFile.cWX2MB(path), X_OK) == 0;
+#elif defined( __WINDOWS__ )
+   return wxCheckGenericPermission(path, GENERIC_EXECUTE);
+#else
+    // TODO
+    return false;
+#endif
+}
+
 
 //------------------------------------------------------------------------
 // wild character routines