From 66893f980f13b12faa04ff756b096cd1b815b82f Mon Sep 17 00:00:00 2001
From: Jorge Rocha Gualtieri <jorge@jrg.com.br>
Date: Sat, 22 Feb 2020 18:10:28 -0300
Subject: [PATCH] Fix "Monitoring" not detecting all file changes issue

This patch adds an active monitor to detect changes on files since Windows isn't honoring FILE_NOTIFY_CHANGE_SIZE or FILE_NOTIFY_CHANGE_LAST_WRITE on ReadDirectoryChangesW correctly if the file writer keep it opened.
This solution is based on GNU tail for Windows does. It does it at
static void tail_forever (struct File_spec *f, int nfiles, double sleep_interval) on tail.c.

Fix #3142, fix #4955, fix #4527, close #7969
---
 PowerEditor/src/NppIO.cpp                     | 13 ++++-
 .../ReadDirectoryChanges/ReadFileChanges.cpp  | 47 +++++++++++++++++++
 .../ReadDirectoryChanges/ReadFileChanges.h    | 29 ++++++++++++
 PowerEditor/visual.net/notepadPlus.vcxproj    |  3 ++
 4 files changed, 90 insertions(+), 2 deletions(-)
 create mode 100644 PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.cpp
 create mode 100644 PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.h

diff --git a/PowerEditor/src/NppIO.cpp b/PowerEditor/src/NppIO.cpp
index 504b3837..9bcbbf17 100644
--- a/PowerEditor/src/NppIO.cpp
+++ b/PowerEditor/src/NppIO.cpp
@@ -35,6 +35,7 @@
 #include "VerticalFileSwitcher.h"
 #include "functionListPanel.h"
 #include "ReadDirectoryChanges.h"
+#include "ReadFileChanges.h"
 #include <tchar.h>
 #include <unordered_set>
 
@@ -60,13 +61,16 @@ DWORD WINAPI Notepad_plus::monitorFileOnChange(void * params)
 	CReadDirectoryChanges changes;
 	changes.AddDirectory(folderToMonitor, true, dwNotificationFlags);
 
+	CReadFileChanges fChanges;
+	fChanges.AddFile(fullFileName, FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_SIZE);
+
 	HANDLE changeHandles[] = { buf->getMonitoringEvent(), changes.GetWaitHandle() };
 
 	bool toBeContinued = true;
 
 	while (toBeContinued)
 	{
-		DWORD waitStatus = ::WaitForMultipleObjects(_countof(changeHandles), changeHandles, FALSE, INFINITE);
+		DWORD waitStatus = ::WaitForMultipleObjects(_countof(changeHandles), changeHandles, FALSE, 250);
 		switch (waitStatus)
 		{
 			case WAIT_OBJECT_0 + 0:
@@ -102,7 +106,11 @@ DWORD WINAPI Notepad_plus::monitorFileOnChange(void * params)
 				}
 			}
 			break;
-
+			case WAIT_TIMEOUT:
+				if (fChanges.DetectChanges()) {
+					::PostMessage(h, NPPM_INTERNAL_RELOADSCROLLTOEND, reinterpret_cast<WPARAM>(buf), 0);
+				}
+				break;
 			case WAIT_IO_COMPLETION:
 				// Nothing to do.
 			break;
@@ -112,6 +120,7 @@ DWORD WINAPI Notepad_plus::monitorFileOnChange(void * params)
 	// Just for sample purposes. The destructor will
 	// call Terminate() automatically.
 	changes.Terminate();
+	fChanges.Terminate();
 	delete monitorInfo;
 	return EXIT_SUCCESS;
 }
diff --git a/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.cpp b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.cpp
new file mode 100644
index 00000000..ee0496cf
--- /dev/null
+++ b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.cpp
@@ -0,0 +1,47 @@
+#include "ReadFileChanges.h"
+
+
+
+CReadFileChanges::CReadFileChanges()
+{
+	_szFile = NULL;
+	_dwNotifyFilter = 0;
+}
+
+
+CReadFileChanges::~CReadFileChanges()
+{
+}
+
+
+BOOL CReadFileChanges::DetectChanges() {
+
+	WIN32_FILE_ATTRIBUTE_DATA fInfo;
+	BOOL rValue = FALSE;
+	::GetFileAttributesEx(_szFile, GetFileExInfoStandard, &fInfo);
+
+	if ((_dwNotifyFilter & FILE_NOTIFY_CHANGE_SIZE) && (fInfo.nFileSizeHigh != _lastFileInfo.nFileSizeHigh || fInfo.nFileSizeLow != _lastFileInfo.nFileSizeLow)) {
+		rValue = TRUE;
+	}
+
+	if ((_dwNotifyFilter & FILE_NOTIFY_CHANGE_LAST_WRITE) && (fInfo.ftLastWriteTime.dwHighDateTime != _lastFileInfo.ftLastWriteTime.dwHighDateTime || fInfo.ftLastWriteTime.dwLowDateTime != _lastFileInfo.ftLastWriteTime.dwLowDateTime)) {
+		rValue = TRUE;
+	}
+
+	_lastFileInfo = fInfo;
+	return rValue;
+}
+
+void CReadFileChanges::AddFile(LPCTSTR szFile, DWORD dwNotifyFilter)
+{
+	_szFile = szFile;
+	_dwNotifyFilter = dwNotifyFilter;
+	::GetFileAttributesEx(szFile, GetFileExInfoStandard, &_lastFileInfo);
+}
+
+
+void CReadFileChanges::Terminate()
+{
+	_szFile = NULL;
+	_dwNotifyFilter = 0;
+}
diff --git a/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.h b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.h
new file mode 100644
index 00000000..272fa5dc
--- /dev/null
+++ b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadFileChanges.h
@@ -0,0 +1,29 @@
+#pragma once
+
+
+#include <stdio.h>
+
+#ifndef VC_EXTRALEAN
+#define VC_EXTRALEAN            // Exclude rarely-used stuff from Windows headers
+#endif
+
+
+#include <windows.h>
+
+
+class CReadFileChanges
+{
+public:
+	CReadFileChanges();
+	~CReadFileChanges();
+	void AddFile(LPCTSTR szDirectory, DWORD dwNotifyFilter);
+	BOOL DetectChanges();
+	void Terminate();
+
+private:
+	LPCTSTR _szFile;
+	DWORD _dwNotifyFilter;
+	WIN32_FILE_ATTRIBUTE_DATA _lastFileInfo;
+
+};
+
diff --git a/PowerEditor/visual.net/notepadPlus.vcxproj b/PowerEditor/visual.net/notepadPlus.vcxproj
index 80ff92bf..f801b02a 100755
--- a/PowerEditor/visual.net/notepadPlus.vcxproj
+++ b/PowerEditor/visual.net/notepadPlus.vcxproj
@@ -394,6 +394,7 @@ copy ..\src\contextMenu.xml ..\bin64\contextMenu.xml
     <ClCompile Include="..\src\WinControls\FileBrowser\fileBrowser.cpp" />
     <ClCompile Include="..\src\WinControls\ReadDirectoryChanges\ReadDirectoryChanges.cpp" />
     <ClCompile Include="..\src\WinControls\ReadDirectoryChanges\ReadDirectoryChangesPrivate.cpp" />
+    <ClCompile Include="..\src\WinControls\ReadDirectoryChanges\ReadFileChanges.cpp" />
   </ItemGroup>
   <ItemGroup>
     <Image Include="..\src\icons\allChars_off.ico" />
@@ -673,6 +674,8 @@ copy ..\src\contextMenu.xml ..\bin64\contextMenu.xml
     <ClInclude Include="..\src\WinControls\ReadDirectoryChanges\ReadDirectoryChanges.h" />
     <ClInclude Include="..\src\WinControls\ReadDirectoryChanges\ReadDirectoryChangesPrivate.h" />
     <ClInclude Include="..\src\WinControls\ReadDirectoryChanges\ThreadSafeQueue.h" />
+    <ClInclude Include="..\src\WinControls\ReadDirectoryChanges\ReadFileChanges.h" />
+	
   </ItemGroup>
   <ItemGroup>
     <Manifest Include="..\src\notepad++.exe.manifest" />