From 9fb72ec18e1a861a74575c8e1378477e6e51d5c6 Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Mon, 1 Jun 2015 19:31:05 -0400
Subject: [PATCH] Expander: don't scroll to the end if the user modifies the
 scrollbar position.

Fixes #11027. This preserves the functionality of scroll-to-end while
allowing the user to interrupt it (and resume it, in the case of
extremely long archives).
---
 src/apps/expander/ExpanderWindow.cpp | 20 +++++++++++++++-----
 src/apps/expander/ExpanderWindow.h   |  2 ++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/apps/expander/ExpanderWindow.cpp b/src/apps/expander/ExpanderWindow.cpp
index 63d2cdaf02..44b122e8c5 100644
--- a/src/apps/expander/ExpanderWindow.cpp
+++ b/src/apps/expander/ExpanderWindow.cpp
@@ -91,8 +91,8 @@ ExpanderWindow::ExpanderWindow(BRect frame, const entry_ref* ref,
 	fListingText->SetWordWrap(false);
 	BFont font = be_fixed_font;
 	fListingText->SetFontAndColor(&font);
-	BScrollView* scrollView = new BScrollView("", fListingText,
-		B_INVALIDATE_AFTER_LAYOUT, true, true);
+	fScrollView = new BScrollView("", fListingText,	B_INVALIDATE_AFTER_LAYOUT,
+		true, true);
 
 	// workaround to let the layout manager estimate
 	// the width of status view and fix the #5289
@@ -127,14 +127,14 @@ ExpanderWindow::ExpanderWindow(BRect frame, const entry_ref* ref,
 					.End()
 				.End()
 			.End()
-			.Add(scrollView)
+			.Add(fScrollView)
 			.SetInsets(spacing, spacing, spacing, spacing)
 		.End()
 	.End();
 
 	pathLayout->SetExplicitMaxSize(BSize(B_SIZE_UNLIMITED, B_SIZE_UNSET));
 	size = GetLayout()->View()->PreferredSize();
-	fSizeLimit = size.Height() - scrollView->PreferredSize().height - spacing;
+	fSizeLimit = size.Height() - fScrollView->PreferredSize().height - spacing;
 
 	ResizeTo(Bounds().Width(), fSizeLimit);
 	SetSizeLimits(size.Width(), 32767.0f, fSizeLimit, fSizeLimit);
@@ -369,6 +369,12 @@ ExpanderWindow::MessageReceived(BMessage* message)
 
 		case 'outp':
 			if (!fExpandingStarted && fListingStarted) {
+				// Check if the vertical scroll bar is at the end
+				float max, pos;
+				fScrollView->ScrollBar(B_VERTICAL)->GetRange(NULL, &max);
+				pos = fScrollView->ScrollBar(B_VERTICAL)->Value();
+				bool atEnd = (pos == max);
+
 				BString string;
 				int32 i = 0;
 				while (message->FindString("output", i++, &string) == B_OK) {
@@ -379,7 +385,11 @@ ExpanderWindow::MessageReceived(BMessage* message)
 
 					fListingText->Insert(string.String());
 				}
-				fListingText->ScrollToSelection();
+
+				if (atEnd && fScrollView->ScrollBar(B_VERTICAL)->Value() == pos) {
+					fScrollView->ScrollBar(B_VERTICAL)->GetRange(NULL, &max);
+					fScrollView->ScrollBar(B_VERTICAL)->SetValue(max);
+				}
 			} else if (fExpandingStarted) {
 				BString string;
 				int32 i = 0;
diff --git a/src/apps/expander/ExpanderWindow.h b/src/apps/expander/ExpanderWindow.h
index 8d324cd7a7..fbbfac7e19 100644
--- a/src/apps/expander/ExpanderWindow.h
+++ b/src/apps/expander/ExpanderWindow.h
@@ -20,6 +20,7 @@
 class BCheckBox;
 class BMenu;
 class BLayout;
+class BScrollView;
 class BStringView;
 class BTextControl;
 class BTextView;
@@ -80,6 +81,7 @@ private:
 			BTextControl*		fDestText;
 			BStringView*		fStatusView;
 			BTextView*			fListingText;
+			BScrollView*		fScrollView;
 
 			ExpanderThread*		fListingThread;
 			bool				fListingStarted;