readerrolling(fix): detect end of book properly

frontend/apps/reader/modules/readerrolling.lua

@@ -357,11 +357,6 @@ end
 
 function ReaderRolling:onGotoViewRel(diff)
     DEBUG("goto relative screen:", diff, ", in mode: ", self.view.view_mode)
-    local prev_xp
-    -- save xpointer to check whether we reach the end of the book
-    if diff > 0 then
-        prev_xp = self.xpointer
-    end
     if self.view.view_mode == "scroll" then
         local pan_diff = diff * self.ui.dimen.h
         if self.show_overlap_enable then
@@ -371,15 +366,20 @@ function ReaderRolling:onGotoViewRel(diff)
                 pan_diff = pan_diff + self.overlap
             end
         end
+        local old_pos = self.current_pos
         self:_gotoPos(self.current_pos + pan_diff)
+        if diff > 0 and old_pos == self.current_pos then
+            self.ui:handleEvent(Event:new("EndOfBook"))
+        end
     elseif self.view.view_mode == "page" then
         local page_count = self.ui.document:getVisiblePageCount()
+        local old_page = self.current_page
         self:_gotoPage(self.current_page + diff*page_count)
+        if diff > 0 and old_page == self.current_page then
+            self.ui:handleEvent(Event:new("EndOfBook"))
+        end
     end
     self.xpointer = self.ui.document:getXPointer()
-    if self.xpointer == prev_xp then
-        self.ui:handleEvent(Event:new("EndOfBook"))
-    end
     return true
 end
 

spec/unit/readerrolling_spec.lua

@@ -51,18 +51,57 @@ describe("Readerrolling module", function()
                 assert.are.same(toc:getPreviousChapter(i, 0), rolling.current_page)
             end
         end)
-        it("should emit EndOfBook event at the end", function()
+        it("should emit EndOfBook event at the end of sample epub", function()
-            rolling:onGotoPage(readerui.document:getPageCount())
             local called = false
             readerui.onEndOfBook = function()
                 called = true
             end
+            -- check beginning of the book
+            rolling:onGotoPage(1)
+            assert.is.falsy(called)
+            rolling:onGotoViewRel(-1)
+            rolling:onGotoViewRel(-1)
+            assert.is.falsy(called)
+            -- check end of the book
+            rolling:onGotoPage(readerui.document:getPageCount())
+            assert.is.falsy(called)
             rolling:onGotoViewRel(1)
+            assert.is.truthy(called)
             rolling:onGotoViewRel(1)
             assert.is.truthy(called)
             readerui.onEndOfBook = nil
         end)
+
+        it("should emit EndOfBook event at the end sample txt", function()
+            local sample_txt = "spec/front/unit/data/sample.txt"
+            local txt_readerui = ReaderUI:new{
+                document = DocumentRegistry:openDocument(sample_txt),
+            }
+            local called = false
+            txt_readerui.onEndOfBook = function()
+                called = true
+            end
+            local txt_rolling = txt_readerui.rolling
+            -- check beginning of the book
+            txt_rolling:onGotoPage(1)
+            assert.is.falsy(called)
+            txt_rolling:onGotoViewRel(-1)
+            txt_rolling:onGotoViewRel(-1)
+            assert.is.falsy(called)
+            -- not at the end of the book
+            txt_rolling:onGotoPage(3)
+            assert.is.falsy(called)
+            txt_rolling:onGotoViewRel(1)
+            assert.is.falsy(called)
+            -- at the end of the book
+            txt_rolling:onGotoPage(txt_readerui.document:getPageCount())
+            assert.is.falsy(called)
+            txt_rolling:onGotoViewRel(1)
+            assert.is.truthy(called)
+            readerui.onEndOfBook = nil
+        end)
     end)
+
     describe("test in landscape screen mode", function()
         it("should go to landscape screen mode", function()
             readerui:handleEvent(Event:new("ChangeScreenMode", "landscape"))
@@ -110,6 +149,7 @@ describe("Readerrolling module", function()
             readerui.onEndOfBook = nil
         end)
     end)
+
     describe("switching screen mode should not change current page number", function()
         it("for portrait-landscape-portrait switching", function()
             for i = 80, 100, 10 do