From 5346868df70227da455355c6730c39829c76c033 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 28 Mar 2014 15:12:04 +0530
Subject: [PATCH] Make MOBI/AZW3 output a little closer to that of current
 kindlegen

---
 src/calibre/ebooks/mobi/writer8/exth.py     | 11 ++++++++---
 src/calibre/ebooks/mobi/writer8/main.py     |  8 ++++----
 src/calibre/ebooks/mobi/writer8/skeleton.py |  2 ++
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/calibre/ebooks/mobi/writer8/exth.py b/src/calibre/ebooks/mobi/writer8/exth.py
index 31792d2156..81a0c7669d 100644
--- a/src/calibre/ebooks/mobi/writer8/exth.py
+++ b/src/calibre/ebooks/mobi/writer8/exth.py
@@ -51,7 +51,8 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
     nrecs = 0
 
     for term in metadata:
-        if term not in EXTH_CODES: continue
+        if term not in EXTH_CODES:
+            continue
         code = EXTH_CODES[term]
         items = metadata[term]
         if term == 'creator':
@@ -148,7 +149,7 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
         nrecs += 1
 
     if be_kindlegen2:
-        vals = {204:201, 205:2, 206:5, 207:0}
+        vals = {204:202, 205:2, 206:9, 207:0}
     elif is_periodical:
         # Pretend to be amazon's super secret periodical generator
         vals = {204:201, 205:2, 206:0, 207:101}
@@ -158,6 +159,10 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
     for code, val in vals.iteritems():
         exth.write(pack(b'>III', code, 12, val))
         nrecs += 1
+    if be_kindlegen2:
+        revnum = b'0730-890adc2'
+        exth.write(pack(b'>II', 535, 8 + len(revnum)) + revnum)
+        nrecs += 1
 
     if cover_offset is not None:
         exth.write(pack(b'>III', EXTH_CODES['coveroffset'], 12,
@@ -200,7 +205,7 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
 
     exth = exth.getvalue()
     trail = len(exth) % 4
-    pad = b'\0' * (4 - trail) # Always pad w/ at least 1 byte
+    pad = b'\0' * (4 - trail)  # Always pad w/ at least 1 byte
     exth = [b'EXTH', pack(b'>II', len(exth) + 12, nrecs), exth, pad]
     return b''.join(exth)
 
diff --git a/src/calibre/ebooks/mobi/writer8/main.py b/src/calibre/ebooks/mobi/writer8/main.py
index 781fdec779..b291691d62 100644
--- a/src/calibre/ebooks/mobi/writer8/main.py
+++ b/src/calibre/ebooks/mobi/writer8/main.py
@@ -254,12 +254,12 @@ class KF8Writer(object):
                     if id_ is not None:
                         tag.attrib['id'] = id_
                 if id_ is not None or barename(tag.tag).lower() in aid_able_tags:
-                    aid = aidbase + j
-                    tag.attrib['aid'] = to_base(aid, base=32)
+                    aid = to_base(aidbase + j, base=32)
+                    tag.set('aid', aid)
                     if tag.tag == XHTML('body'):
-                        self.id_map[(item.href, '')] = tag.attrib['aid']
+                        self.id_map[(item.href, '')] = aid
                     if id_ is not None:
-                        self.id_map[(item.href, id_)] = tag.attrib['aid']
+                        self.id_map[(item.href, id_)] = aid
 
                     j += 1
 
diff --git a/src/calibre/ebooks/mobi/writer8/skeleton.py b/src/calibre/ebooks/mobi/writer8/skeleton.py
index 3bf56c24d6..26106e4665 100644
--- a/src/calibre/ebooks/mobi/writer8/skeleton.py
+++ b/src/calibre/ebooks/mobi/writer8/skeleton.py
@@ -165,6 +165,8 @@ class Chunker(object):
 
         for i, item in enumerate(self.oeb.spine):
             root = self.remove_namespaces(self.data(item))
+            for child in root.xpath('//*[@aid]'):
+                child.set('aid', child.attrib.pop('aid'))  # kindlegen always puts the aid last
             body = root.xpath('//body')[0]
             body.tail = '\n'