File system watcher

AUTHORS

@@ -1,6 +1,9 @@
 
 Stefan Buschmann <stefan.buschmann@hpi.de> <buschmann@cginternals.com>
-Daniel Limberger <daniel.limberger@hpi.de> <limberger@cginternals.com> 
+Daniel Limberger <daniel.limberger@hpi.de> <limberger@cginternals.com>
 Willy Scheibel <willy.scheibel@hpi.de> <scheibel@cginternals.com>
 
-Thanks to all Contributors
+
+Thanks to all Contributors:
+
+Robert Bielik (https://github.com/robiwano)

source/cppfs/CMakeLists.txt

@@ -56,9 +56,13 @@ set(headers
     ${include_path}/FileIterator.h
     ${include_path}/FileVisitor.h
     ${include_path}/FunctionalFileVisitor.h
+    ${include_path}/FileWatcher.h
+    ${include_path}/FileEventHandler.h
+    ${include_path}/FunctionalFileEventHandler.h
     ${include_path}/AbstractFileSystem.h
     ${include_path}/AbstractFileHandleBackend.h
     ${include_path}/AbstractFileIteratorBackend.h
+    ${include_path}/AbstractFileWatcherBackend.h
     ${include_path}/InputStream.h
     ${include_path}/OutputStream.h
     ${include_path}/LoginCredentials.h
@@ -81,9 +85,13 @@ set(sources
     ${source_path}/FileIterator.cpp
     ${source_path}/FileVisitor.cpp
     ${source_path}/FunctionalFileVisitor.cpp
+    ${source_path}/FileWatcher.cpp
+    ${source_path}/FileEventHandler.cpp
+    ${source_path}/FunctionalFileEventHandler.cpp
     ${source_path}/AbstractFileSystem.cpp
     ${source_path}/AbstractFileHandleBackend.cpp
     ${source_path}/AbstractFileIteratorBackend.cpp
+    ${source_path}/AbstractFileWatcherBackend.cpp
     ${source_path}/InputStream.cpp
     ${source_path}/OutputStream.cpp
     ${source_path}/LoginCredentials.cpp
@@ -98,6 +106,26 @@ set(sources
     ${source_path}/${localfs}/LocalFileIterator.cpp
 )
 
+if("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
+    set(headers ${headers}
+        ${include_path}/linux/LocalFileWatcher.h
+    )
+
+    set(sources ${sources}
+        ${source_path}/linux/LocalFileWatcher.cpp
+    )
+endif()
+
+if("${CMAKE_SYSTEM_NAME}" MATCHES "Windows")
+    set(headers ${headers}
+        ${include_path}/windows/LocalFileWatcher.h
+    )
+
+    set(sources ${sources}
+        ${source_path}/windows/LocalFileWatcher.cpp
+    )
+endif()
+
 if (OPTION_BUILD_SSH_BACKEND)
     set(headers ${headers}
         ${include_path}/ssh/SshFileSystem.h
@@ -114,7 +142,7 @@ if (OPTION_BUILD_SSH_BACKEND)
         ${source_path}/ssh/SshInputStreamBuffer.cpp
         ${source_path}/ssh/SshOutputStreamBuffer.cpp
     )
-endif ()
+endif()
 
 # Group source files
 set(header_group "Header Files (API)")

source/cppfs/include/cppfs/AbstractFileSystem.h

@@ -2,6 +2,7 @@
 #pragma once
 
 
+#include <memory>
 #include <string>
 
 #include <cppfs/cppfs_api.h>
@@ -12,6 +13,8 @@ namespace cppfs
 
 
 class FileHandle;
+class FileWatcher;
+class AbstractFileWatcherBackend;
 
 
 /**
@@ -50,6 +53,18 @@ class CPPFS_API AbstractFileSystem
     *    Path to file or directory
     */
     virtual FileHandle open(std::string && path) = 0;
+
+    /**
+    *  @brief
+    *    Create a watcher for the file system
+    *
+    *  @param[in] fileWatcher
+    *    File watcher that owns the backend
+    *
+    *  @return
+    *    Watcher backend (must NOT be null!)
+    */
+    virtual std::unique_ptr<AbstractFileWatcherBackend> createFileWatcher(FileWatcher & fileWatcher) = 0;
 };
 
 

source/cppfs/include/cppfs/AbstractFileWatcherBackend.h

@@ -0,0 +1,101 @@
+
+#pragma once
+
+
+#include <memory>
+
+#include <cppfs/cppfs.h>
+
+
+namespace cppfs
+{
+
+
+class FileHandle;
+class FileWatcher;
+class AbstractFileSystem;
+
+
+/**
+*  @brief
+*    Interface for file watchers
+*/
+class CPPFS_API AbstractFileWatcherBackend
+{
+    friend class FileWatcher;
+
+
+public:
+    /**
+    *  @brief
+    *    Constructor
+    *
+    *  @param[in] fileWatcher
+    *    File watcher that owns the backend (must NOT be null!)
+    */
+    AbstractFileWatcherBackend(FileWatcher * fileWatcher);
+
+    /**
+    *  @brief
+    *    Destructor
+    */
+    virtual ~AbstractFileWatcherBackend();
+
+    /**
+    *  @brief
+    *    Get file system
+    *
+    *  @return
+    *    File system (must NOT be null)
+    */
+    virtual AbstractFileSystem * fs() const = 0;
+
+    /**
+    *  @brief
+    *    Watch directory
+    *
+    *  @param[in] dir
+    *    Handle to directory that shall be watched
+    *  @param[in] events
+    *    Events that are watched (combination of FileEvent values)
+    *  @param[in] recursive
+    *    Watch file system recursively?
+    */
+    virtual void add(FileHandle & dir, unsigned int events, RecursiveMode recursive) = 0;
+
+    /**
+    *  @brief
+    *    Start watching files
+    *
+    *  @param[in] timeout
+    *    Timeout value in milliseconds. If less than zero, timeout is infinite and the function blocks.
+    *
+    *  @remarks
+    *    This function shall watch the file system and block until one or more
+    *    events have occured, or if the timeout has been exceeded (timeout >= 0).
+    *    For each event, onFileEvent has to be called with the type of the event and
+    *    a file handle to the file or directory. After all events have been
+    *    processed, the function shall return.
+    */
+    virtual void watch(int timeout) = 0;
+
+
+protected:
+    /**
+    *  @brief
+    *    Called on each file event
+    *
+    *  @param[in] fh
+    *    File handle
+    *  @param[in] event
+    *    Type of event that has occured
+    */
+    void onFileEvent(FileHandle & fh, FileEvent event);
+
+
+protected:
+    FileWatcher * m_fileWatcher; ///< File watcher that owns the backend (never null)
+};
+
+
+} // namespace cppfs

source/cppfs/include/cppfs/FileEventHandler.h

@@ -0,0 +1,91 @@
+
+#pragma once
+
+
+#include <cppfs/cppfs.h>
+
+
+namespace cppfs
+{
+
+
+class FileHandle;
+
+
+/**
+*  @brief
+*    Handler that is informed about file system events
+*
+*  @remarks
+*    Use FileWatcher to register file event handlers.
+*/
+class CPPFS_API FileEventHandler
+{
+    friend class FileWatcher;
+
+
+public:
+    /**
+    *  @brief
+    *    Constructor
+    */
+    FileEventHandler();
+
+    /**
+    *  @brief
+    *    Destructor
+    */
+    virtual ~FileEventHandler();
+
+
+protected:
+    /**
+    *  @brief
+    *    Called on file event
+    *
+    *  @param[in] fh
+    *    Handle to file or directory
+    *  @param[in] event
+    *    Type of event that has occured
+    */
+    virtual void onFileEvent(FileHandle & fh, FileEvent event);
+
+    /**
+    *  @brief
+    *    Called when a file or directory has been created
+    *
+    *  @param[in] fh
+    *    Handle to file or directory
+    */
+    virtual void onFileCreated(FileHandle & fh);
+
+    /**
+    *  @brief
+    *    Called when a file or directory has been removed
+    *
+    *  @param[in] fh
+    *    Handle to file or directory
+    */
+    virtual void onFileRemoved(FileHandle & fh);
+
+    /**
+    *  @brief
+    *    Called when a file or directory has been modified
+    *
+    *  @param[in] fh
+    *    Handle to file or directory
+    */
+    virtual void onFileModified(FileHandle & fh);
+
+    /**
+    *  @brief
+    *    Called when file attributes have been modified
+    *
+    *  @param[in] fh
+    *    Handle to file or directory
+    */
+    virtual void onFileAttrChanged(FileHandle & fh);
+};
+
+
+} // namespace cppfs

source/cppfs/include/cppfs/FileHandle.h

@@ -8,17 +8,19 @@
 #include <vector>
 #include <string>
 
-#include <cppfs/cppfs_api.h>
+#include <cppfs/cppfs.h>
 #include <cppfs/AbstractFileHandleBackend.h>
 
 
 namespace cppfs
 {
 
 
+class AbstractFileSystem;
 class FileIterator;
 class FileVisitor;
 class Tree;
+class FileWatcher;
 
 
 /**
@@ -104,6 +106,15 @@ class CPPFS_API FileHandle
     */
     FileHandle & operator=(FileHandle && fileHandle);
 
+    /**
+    *  @brief
+    *    Get file system
+    *
+    *  @return
+    *    File system (can be null)
+    */
+    AbstractFileSystem * fs() const;
+
     /**
     *  @brief
     *    Get path
@@ -478,6 +489,26 @@ class CPPFS_API FileHandle
     */
     bool remove();
 
+    /**
+    *  @brief
+    *    Create file system watcher for this file handle
+    *
+    *  @param[in] events
+    *    Events that are watched (combination of FileEvent values)
+    *  @param[in] recursive
+    *    Watch file system recursively?
+    *
+    *  @return
+    *    File watcher
+    *
+    *  @remarks
+    *    This is a shortcut for creating a FileWatcher and adding file handles to watch.
+    *    It will only work if the file handle points to a valid directory.
+    *    To watch more than one directory at a time, use FileWatcher and add.
+    *    Avoid creating more than one FileWatcher, as OS limits can be reached.
+    */
+    FileWatcher watch(unsigned int events = FileCreated | FileRemoved | FileModified | FileAttrChanged, RecursiveMode recursive = Recursive);
+
     /**
     *  @brief
     *    Create input stream to read from the file