Hide non-linear fragments

Add option to hide (skip) non-linear fragments, only working
in 1-page mode. Tweaks mostly to footer, toc and skim code
to make it clear(er) which pages belong to linear or non-linear
fragments.

frontend/document/credocument.lua

@@ -58,6 +58,11 @@ local CreDocument = Document:new{
     default_css = "./data/cr3.css",
     provider = "crengine",
     provider_name = "Cool Reader Engine",
+
+    hide_nonlinear_flows = false,
+    flows = {},
+    page_in_flow = {},
+    last_linear_page = nil,
 }
 
 -- NuPogodi, 20.05.12: inspect the zipfile content
@@ -283,10 +288,188 @@ function CreDocument:updateColorRendering()
     end
 end
 
+function CreDocument:setHideNonlinearFlows(hide_nonlinear_flows)
+    if hide_nonlinear_flows ~= self.hide_nonlinear_flows then
+        self.hide_nonlinear_flows = hide_nonlinear_flows
+        self._document:setIntProperty("crengine.doc.nonlinear.pagebreak.force", self.hide_nonlinear_flows and 1 or 0)
+    end
+end
+
 function CreDocument:getPageCount()
     return self._document:getPages()
 end
 
+-- Whether the document has any non-linear flow to care about
+function CreDocument:hasNonLinearFlows()
+    return self._document:hasNonLinearFlows()
+end
+
+-- Whether non-linear flows (if any) will be hidden
+function CreDocument:hasHiddenFlows()
+    return self.flows[1] ~= nil
+end
+
+-- Get the next/prev page number, skipping non-linear flows,
+-- i.e. the next/prev page that is either in the current
+-- flow or in the linear flow (flow 0)
+-- If "page" is 0, these give the initial and final linear pages
+function CreDocument:getNextPage(page)
+    if self:hasHiddenFlows() then
+        if page < 0 or page >= self:getPageCount() then
+            return 0
+        elseif page == 0 then
+            return self:getFirstPageInFlow(0)
+        end
+        local flow = self:getPageFlow(page)
+        local start_page = page + 1
+        local end_page = self:getLastLinearPage()
+        local test_page = start_page
+        -- max to ensure at least one iteration
+        -- (in case the current flow goes after all linear pages)
+        while test_page <= math.max(end_page, start_page) do
+            local test_page_flow = self:getPageFlow(test_page)
+            if test_page_flow == flow or test_page_flow == 0 then
+                -- same flow as current, or linear flow, this is a "good" page
+                return test_page
+            elseif test_page_flow > 0 then
+                -- some other non-linear flow, skip all pages in this flow
+                test_page = test_page + self:getTotalPagesInFlow(test_page_flow)
+            else
+                -- went beyond the last page
+                break
+            end
+        end
+        return 0
+    else
+        return Document.getNextPage(self, page)
+    end
+end
+
+function CreDocument:getPrevPage(page)
+    if self:hasHiddenFlows() then
+        if page < 0 or page > self:getPageCount() then
+            return 0
+        elseif page == 0 then
+            return self:getLastLinearPage()
+        end
+        local flow = self:getPageFlow(page)
+        local start_page = page - 1
+        local end_page = self:getFirstPageInFlow(0)
+        local test_page = start_page
+        -- min to ensure at least one iteration
+        -- (in case the current flow goes before all linear pages)
+        while test_page >= math.min(end_page, start_page) do
+            local test_page_flow = self:getPageFlow(test_page)
+            if test_page_flow == flow or test_page_flow == 0 then
+                -- same flow as current, or linear flow, this is a "good" page
+                return test_page
+            elseif test_page_flow > 0 then
+                -- some other non-linear flow, skip all pages in this flow
+                test_page = self:getFirstPageInFlow(test_page_flow) - 1
+            else
+                -- went beyond the first page
+                break
+            end
+        end
+        return 0
+    else
+        return Document.getPrevPage(self, page)
+    end
+end
+
+function CreDocument:getPageFlow(page)
+    -- Only report non-linear pages if "hide_nonlinear_flows" is enabled, and in 1-page mode,
+    -- otherwise all pages are linear (flow 0)
+    if self.hide_nonlinear_flows and self._view_mode == self.PAGE_VIEW_MODE and self:getVisiblePageCount() == 1 then
+        return self._document:getPageFlow(page)
+    else
+        return 0
+    end
+end
+
+function CreDocument:getLastLinearPage()
+    return self.last_linear_page
+end
+
+function CreDocument:getFirstPageInFlow(flow)
+    return self.flows[flow][1]
+end
+
+function CreDocument:getTotalPagesInFlow(flow)
+    return self.flows[flow][2]
+end
+
+function CreDocument:getPageNumberInFlow(page)
+    if self:hasHiddenFlows() then
+        return self.page_in_flow[page]
+    else
+        return page
+    end
+end
+
+function CreDocument:cacheFlows()
+    -- Build the cache tables "flows" and "page_in_flow", if there are
+    -- any non-linear flows in the source document. Also set the value
+    -- of "last_linear_page", to possibly speed up counting in documents
+    -- with many non-linear pages at the end.
+    -- flows[i] contains {ini, num}, where ini is the first page in flow i,
+    --          and num is the total number of pages in the flow.
+    -- page_in_flow[i] contains the number of page i with its flow.
+    --
+    -- So, flows[0][1] is the first page in the linear flow,
+    -- and page_in_flow[flows[0][1]] must be 1, because it is the first
+    self.flows = {}
+    self.page_in_flow = {}
+    if self:hasNonLinearFlows() and self.hide_nonlinear_flows then
+        for i=1,self:getPageCount() do
+            local flow = self:getPageFlow(i)
+            if self.flows[flow] ~= nil then
+                self.flows[flow][2] = self.flows[flow][2]+1
+            else
+                self.flows[flow] = {i, 1}
+            end
+            self.page_in_flow[i] = self.flows[flow][2]
+            if flow == 0 then
+                self.last_linear_page = i
+            end
+        end
+    else
+        self.last_linear_page = self:getPageCount()
+        self.flows[0] = {1, self.last_linear_page}
+    end
+end
+
+function CreDocument:getTotalPagesLeft(page)
+    if self:hasHiddenFlows() then
+        local pages_left
+        local last_linear = self:getLastLinearPage()
+        if page > last_linear then
+            -- If beyond the last linear page, count only the pages in the current flow
+            local flow = self:getPageFlow(page)
+            pages_left = self:getTotalPagesInFlow(flow) - self:getPageNumberInFlow(page)
+        else
+            -- Otherwise, count all pages until the last linear,
+            -- except the flows that start (and end) between
+            -- the current page and the last linear
+            pages_left = last_linear - page
+            for flow, tab in ipairs(self.flows) do
+                -- tab[1] is the initial page of the flow
+                -- tab[2] is the total number of pages in the flow
+                if tab[1] > last_linear then
+                     break
+                end
+                -- strict >, to make sure we include pages in the current flow
+                if tab[1] > page then
+                     pages_left = pages_left - tab[2]
+                end
+            end
+        end
+        return pages_left
+    else
+        return Document.getTotalPagesLeft(self, page)
+    end
+end
+
 function CreDocument:getCoverPageImage()
     -- no need to render document in order to get cover image
     if not self:loadDocument() then
@@ -578,7 +761,7 @@ function CreDocument:gotoPos(pos)
 end
 
 function CreDocument:gotoPage(page)
-    logger.dbg("CreDocument: goto page", page)
+    logger.dbg("CreDocument: goto page", page, "flow", self:getPageFlow(page))
     self._document:gotoPage(page)
 end
 
@@ -766,6 +949,9 @@ function CreDocument:setViewMode(new_mode)
             self._view_mode = self.PAGE_VIEW_MODE
         end
         self._document:setViewMode(self._view_mode)
+        if self.hide_nonlinear_flows then
+            self:cacheFlows()
+        end
     end
 end
 
@@ -1272,6 +1458,7 @@ function CreDocument:setupCallCache()
             elseif name:sub(1,6) == "enable" then add_reset = true
             elseif name == "zoomFont" then add_reset = true -- not used by koreader
             elseif name == "resetCallCache" then add_reset = true
+            elseif name == "cacheFlows" then add_reset = true
 
             -- These may have crengine do native highlight or unhighlight
             -- (we could keep the original buffer and use a scratch buffer while
@@ -1313,6 +1500,11 @@ function CreDocument:setupCallCache()
             elseif name == "getCacheFilePath" then no_wrap = true
             elseif name == "getStatistics" then no_wrap = true
             elseif name == "getNormalizedXPointer" then no_wrap = true
+            elseif name == "getNextPage" then no_wrap = true
+            elseif name == "getPrevPage" then no_wrap = true
+            elseif name == "getPageFlow" then no_wrap = true
+            elseif name == "getPageNumberInFlow" then no_wrap = true
+            elseif name == "getTotalPagesLeft" then no_wrap = true
 
             -- Some get* have different results by page/pos
             elseif name == "getLinkFromPosition" then cache_by_tag = true