From e1aec91911786b82d2eb39047153687574de37b2 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 25 Jun 2009 16:09:25 -0700
Subject: [PATCH] Improve file locking on windows for config files. Should fix
 #2598 (Calibre 0.6b6 Crash While Converting)

---
 src/calibre/ebooks/oeb/reader.py    |   2 +-
 src/calibre/ebooks/pdf/pdftohtml.py |   2 +-
 src/calibre/utils/lock.py           | 109 ++++++++++++++++++++++++----
 3 files changed, 97 insertions(+), 16 deletions(-)

diff --git a/src/calibre/ebooks/oeb/reader.py b/src/calibre/ebooks/oeb/reader.py
index 9a637c1a24..ab8d9976fd 100644
--- a/src/calibre/ebooks/oeb/reader.py
+++ b/src/calibre/ebooks/oeb/reader.py
@@ -140,7 +140,7 @@ class OEBReader(object):
             mi.language = get_lang()
         meta_info_to_oeb_metadata(mi, self.oeb.metadata, self.logger)
         bookid = "urn:uuid:%s" % str(uuid.uuid4()) if mi.application_id is None \
-                else mi.applicaion_id
+                else mi.application_id
         self.oeb.metadata.add('identifier', bookid, id='calibre-uuid')
         self.oeb.uid = self.oeb.metadata.identifier[0]
 
diff --git a/src/calibre/ebooks/pdf/pdftohtml.py b/src/calibre/ebooks/pdf/pdftohtml.py
index 11631c7fe0..9293d616ac 100644
--- a/src/calibre/ebooks/pdf/pdftohtml.py
+++ b/src/calibre/ebooks/pdf/pdftohtml.py
@@ -69,7 +69,7 @@ def pdftohtml(output_dir, pdf_path, no_images):
         if not os.path.exists(index) or os.stat(index).st_size < 100:
             raise DRMError()
 
-        with open(index, 'rb+wb') as i:
+        with open(index, 'r+b') as i:
             raw = i.read()
             raw = '<!-- created by calibre\'s pdftohtml -->\n' + raw
             i.seek(0)
diff --git a/src/calibre/utils/lock.py b/src/calibre/utils/lock.py
index b5d165dcb6..5098c78f90 100644
--- a/src/calibre/utils/lock.py
+++ b/src/calibre/utils/lock.py
@@ -13,6 +13,96 @@ import time, atexit, os
 class LockError(Exception):
     pass
 
+class WindowsExclFile(object):
+
+    def __init__(self, path, timeout=20):
+        self.name = path
+        import win32file as w
+        import pywintypes
+
+        while timeout > 0:
+            timeout -= 1
+            try:
+                self._handle = w.CreateFile(path,
+                    w.GENERIC_READ|w.GENERIC_WRITE, # Open for reading and writing
+                    0, # Open exclusive
+                    None, # No security attributes
+                    w.OPEN_ALWAYS, # If file does not exist, create it
+                    w.FILE_ATTRIBUTE_NORMAL, #Normal attributes
+                    None, #No template file
+                )
+                break
+            except pywintypes.error, err:
+                if getattr(err, 'args', [-1])[0] in (0x20, 0x21):
+                    time.sleep(1)
+                    continue
+                else:
+                    raise
+
+    def seek(self, amt, frm=0):
+        import win32file as w
+        if frm not in (0, 1, 2):
+            raise ValueError('Invalid from for seek: %s'%frm)
+        frm = {0:w.FILE_BEGIN, 1: w.FILE_CURRENT, 2:w.FILE_END}[frm]
+        if frm is w.FILE_END:
+            amt = 0 - amt
+        w.SetFilePointer(self._handle, amt, frm)
+
+    def tell(self):
+        import win32file as w
+        return w.SetFilePointer(self._handle, 0, w.FILE_CURRENT)
+
+    def flush(self):
+        import win32file as w
+        w.FlushFileBuffers(self._handle)
+
+    def close(self):
+        if self._handle is not None:
+            import win32file as w
+            self.flush()
+            w.CloseHandle(self._handle)
+            self._handle = None
+
+    def read(self, bytes=-1):
+        import win32file as w
+        sz = w.GetFileSize(self._handle)
+        max = sz - self.tell()
+        if bytes < 0: bytes = max
+        bytes = min(max, bytes)
+        if bytes < 1:
+            return ''
+        hr, ans = w.ReadFile(self._handle, bytes, None)
+        if hr != 0:
+            raise IOError('Error reading file: %s'%hr)
+        return ans
+
+    def readlines(self, sizehint=-1):
+        return self.read().splitlines()
+
+    def write(self, bytes):
+        if isinstance(bytes, unicode):
+            bytes = bytes.encode('utf-8')
+        import win32file as w
+        w.WriteFile(self._handle, bytes, None)
+
+    def truncate(self, size=None):
+        import win32file as w
+        pos = self.tell()
+        if size is None:
+            size = pos
+        t = min(size, pos)
+        self.seek(t)
+        w.SetEndOfFile(self._handle)
+        self.seek(pos)
+
+    def isatty(self):
+        return False
+
+    @property
+    def closed(self):
+        return self._handle is None
+
+
 class ExclusiveFile(object):
 
     def __init__(self, path, timeout=15):
@@ -20,17 +110,10 @@ class ExclusiveFile(object):
         self.timeout = timeout
 
     def __enter__(self):
-        self.file  = open(self.path, 'a+b')
+        self.file  =  WindowsExclFile(self.path, self.timeout) if iswindows else open(self.path, 'a+b')
         self.file.seek(0)
         timeout = self.timeout
-        if iswindows:
-            name = ('Local\\'+(__appname__+self.file.name).replace('\\', '_'))[:201]
-            while self.timeout < 0 or timeout >= 0:
-                self.mutex = win32event.CreateMutex(None, False, name)
-                if win32api.GetLastError() != winerror.ERROR_ALREADY_EXISTS: break
-                time.sleep(1)
-                timeout -= 1
-        else:
+        if not iswindows:
             while self.timeout < 0 or timeout >= 0:
                 try:
                     fcntl.lockf(self.file.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
@@ -38,14 +121,12 @@ class ExclusiveFile(object):
                 except IOError:
                     time.sleep(1)
                     timeout -= 1
-        if timeout < 0 and self.timeout >= 0:
-            self.file.close()
-            raise LockError
+            if timeout < 0 and self.timeout >= 0:
+                self.file.close()
+                raise LockError('Failed to lock')
         return self.file
 
     def __exit__(self, type, value, traceback):
-        if iswindows:
-            win32api.CloseHandle(self.mutex)
         self.file.close()
 
 def _clean_lock_file(file):