EPUB export: handle headings inside sections

On one hand, we don't want to split inside a section as there might be
elements we need to close/open at split boundary, OTOH this is currently
not a problem as we don't produce any output for sections.

So remove the level management for sections (this way allowing headings
to split inside sections), let's get back to this when there is a
concept how e.g. multiple columns would be represented in EPUB.

Use case is when sections are used to just group paragraph together and
mark all of them read-only: in this case it's unexpected that headings
are handled differently to not-in-section ones.

Change-Id: If419624f8eec4a6f676ad7f186484c0035f62626
Reviewed-on: https://gerrit.libreoffice.org/43482Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>

external/libepubgen/libepubgen-epub3.patch.1

@@ -2487,3 +2487,73 @@ index f3b30a6..d822571 100644
 -- 
 2.12.3
 
+From 8166fc972e3d4b930ad0baab164f99b3c717252e Mon Sep 17 00:00:00 2001
+From: Miklos Vajna <vmiklos@collabora.co.uk>
+Date: Wed, 18 Oct 2017 10:04:32 +0200
+Subject: [PATCH] EPUBTextGenerator: handle headings inside sections
+
+On one hand, we don't want to split inside a section as there might be
+elements we need to close/open at split boundary, OTOH this is currently
+not a problem as we don't produce any output for sections.
+
+So remove the level management for sections (this way allowing headings
+to split inside sections), let's get back to this when there is a
+concept how e.g. multiple columns would be represented in EPUB.
+
+Use case is when sections are used to just group paragraph together and
+mark all of them read-only: in this case it's unexpected that headings
+are handled differently to not-in-section ones.
+---
+ src/lib/EPUBHTMLGenerator.cpp      | 14 ++++++++++++--
+ src/lib/EPUBTextGenerator.cpp      |  3 ---
+ src/test/EPUBTextGeneratorTest.cpp | 38 ++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 50 insertions(+), 5 deletions(-)
+
+diff --git a/src/lib/EPUBHTMLGenerator.cpp b/src/lib/EPUBHTMLGenerator.cpp
+index d822571..11bf7de 100644
+--- a/src/lib/EPUBHTMLGenerator.cpp
++++ b/src/lib/EPUBHTMLGenerator.cpp
+@@ -574,8 +574,18 @@ void EPUBHTMLGenerator::closeFooter()
+ }
+ 
+ void EPUBHTMLGenerator::defineSectionStyle(const RVNGPropertyList &) {}
+-void EPUBHTMLGenerator::openSection(const RVNGPropertyList & /* propList */) {}
+-void EPUBHTMLGenerator::closeSection() {}
++
++void EPUBHTMLGenerator::openSection(const RVNGPropertyList & /* propList */)
++{
++  // Once output is produced here, EPUBTextGenerator::openSection() will need
++  // to call EPUBSplitGuard::openLevel().
++}
++
++void EPUBHTMLGenerator::closeSection()
++{
++  // Once output is produced here, EPUBTextGenerator::closeSection() will need
++  // to call EPUBSplitGuard::closeLevel().
++}
+ 
+ void EPUBHTMLGenerator::defineParagraphStyle(const RVNGPropertyList &propList)
+ {
+diff --git a/src/lib/EPUBTextGenerator.cpp b/src/lib/EPUBTextGenerator.cpp
+index 26675af..5d4e8f2 100644
+--- a/src/lib/EPUBTextGenerator.cpp
++++ b/src/lib/EPUBTextGenerator.cpp
+@@ -335,15 +335,12 @@ void EPUBTextGenerator::openSection(const librevenge::RVNGPropertyList &propList
+ {
+   if (m_impl->getSplitGuard().splitOnSize())
+     m_impl->startNewHtmlFile();
+-  m_impl->getSplitGuard().openLevel();
+ 
+   m_impl->getHtml()->openSection(propList);
+ }
+ 
+ void EPUBTextGenerator::closeSection()
+ {
+-  m_impl->getSplitGuard().closeLevel();
+-
+   m_impl->getHtml()->closeSection();
+ }
+ 
+-- 
+2.12.3
+