Fix data loss issue due to no room on disk for saving

Fix #5664, fix #14089, close #14134

PowerEditor/installer/nativeLang/english.xml

@@ -1490,6 +1490,8 @@ Please test those commands and, if needed, re-edit them.
 Alternatively, you can downgrade to Notepad++ v8.5.2 and restore your previous data.
 Notepad++ will backup your old "shortcuts.xml" and save it as "shortcuts.xml.v8.5.2.backup".
 Renaming &quot;shortcuts.xml.v8.5.2.backup&quot; -&gt; &quot;shortcuts.xml&quot;, your commands should be restored and work properly."/><!-- HowToReproduce: Close Notepad++, remove shortcuts.xml.v8.5.2.backup & v852ShortcutsCompatibilityWarning.xml if present, relaunch Notepad++, delete or modify a shortcuts via Shortcut Mapper, close Notepad++, then the message will show up -->
+			<NotEnoughRoom4Saving title="Save failed" message="Failed to save file.
+It seems there's not enough space on disk to save file. Your file is not saved."/>
 		</MessageBox>
 		<ClipboardHistory>
 			<PanelTitle name="Clipboard History"/>

PowerEditor/installer/nativeLang/english_customizable.xml

@@ -1491,6 +1491,9 @@ Please test those commands and, if needed, re-edit them.
 Alternatively, you can downgrade to Notepad++ v8.5.2 and restore your previous data.
 Notepad++ will backup your old "shortcuts.xml" and save it as "shortcuts.xml.v8.5.2.backup".
 Renaming &quot;shortcuts.xml.v8.5.2.backup&quot; -&gt; &quot;shortcuts.xml&quot;, your commands should be restored and work properly."/><!-- HowToReproduce: Close Notepad++, remove shortcuts.xml.v8.5.2.backup & v852ShortcutsCompatibilityWarning.xml if present, relaunch Notepad++, delete or modify a shortcuts via Shortcut Mapper, close Notepad++, then the message will show up -->
+			<NotEnoughRoom4Saving title="Save failed" message="Failed to save file.
+It seems there's not enough space on disk to save file. Your file is not saved."/>
+
 		</MessageBox>
 		<ClipboardHistory>
 			<PanelTitle name="Clipboard History"/>

PowerEditor/src/NppIO.cpp

@@ -628,14 +628,19 @@ bool Notepad_plus::doSave(BufferID id, const TCHAR * filename, bool isCopy)
 		_pluginsManager.notify(&scnN);
 	}
 
-	if (res == SavingStatus::SaveWritingFailed)
+	if (res == SavingStatus::NotEnoughRoom)
 	{
 		_nativeLangSpeaker.messageBox("NotEnoughRoom4Saving",
 			_pPublicInterface->getHSelf(),
-			TEXT("Failed to save file.\nIt seems there's not enough space on disk to save file."),
+			TEXT("Failed to save file.\nIt seems there's not enough space on disk to save file. Your file is not saved."),
 			TEXT("Save failed"),
 			MB_OK);
 	}
+	else if (res == SavingStatus::SaveWritingFailed)
+	{
+		wstring errorMessage = GetLastErrorAsString(GetLastError());
+		::MessageBox(_pPublicInterface->getHSelf(), errorMessage.c_str(), TEXT("Save failed"), MB_OK | MB_ICONWARNING);
+	}
 	else if (res == SavingStatus::SaveOpenFailed)
 	{
 		if (_isAdministrator)

PowerEditor/src/ScintillaComponent/Buffer.cpp

@@ -1114,7 +1114,7 @@ bool FileManager::deleteBufferBackup(BufferID id)
 
 std::mutex save_mutex;
 
-SavingStatus FileManager::saveBuffer(BufferID id, const TCHAR * filename, bool isCopy)
+SavingStatus FileManager::saveBuffer(BufferID id, const TCHAR* filename, bool isCopy)
 {
 	std::lock_guard<std::mutex> lock(save_mutex);
 
@@ -1136,6 +1136,28 @@ SavingStatus FileManager::saveBuffer(BufferID id, const TCHAR * filename, bool i
 			::GetLongPathName(fullpath, fullpath, MAX_PATH);
 		}
 	}
+	
+	wchar_t dirDest[MAX_PATH];
+	wcscpy_s(dirDest, MAX_PATH, fullpath);
+	::PathRemoveFileSpecW(dirDest);
+
+	const wchar_t* currentBufFilePath = buffer->getFullPathName();
+	ULARGE_INTEGER freeBytesForUser;
+	 
+	BOOL getFreeSpaceRes = ::GetDiskFreeSpaceExW(dirDest, &freeBytesForUser, nullptr, nullptr);
+	if (getFreeSpaceRes != FALSE)
+	{
+		int64_t fileSize = buffer->getFileLength();
+		if (fileSize >= 0 && lstrcmp(fullpath, currentBufFilePath) == 0) // if file to save does exist, and it's an operation "Save" but not "Save As"
+		{
+			// if file exists and the operation "Save" but not "Save As", its current length should be considered as part of free room space since the file itself will be overrrided 
+			freeBytesForUser.QuadPart += fileSize;
+		}
+
+		// determinate if free space is enough
+		if (freeBytesForUser.QuadPart < buffer->docLength())
+			return SavingStatus::NotEnoughRoom;
+	}
 
 	if (PathFileExists(fullpath))
 	{

PowerEditor/src/ScintillaComponent/Buffer.h

@@ -53,7 +53,8 @@ enum BufferStatusInfo {
 enum SavingStatus {
 	SaveOK             = 0,
 	SaveOpenFailed     = 1,
-	SaveWritingFailed  = 2
+	SaveWritingFailed  = 2,
+	NotEnoughRoom      = 3
 };
 
 struct BufferViewInfo {