[gnome-code-assistance/wip/completion_python: 1/2] c: add helper file-like object named UnsavedFile

[Igor Gnatenko <ignatenko src gnome org>]

commit c8aa1c48a9d66faa2b487f2f210778f1841c586f
Author: Christian Hergert <christian hergert me>
Date:   Mon Jan 12 02:00:24 2015 -0800

    c: add helper file-like object named UnsavedFile
    
    This helps avoid the situation where a read() is done after the file
    has been closed when ensuring a TU is up to date.

 backends/c/service.py |   28 ++++++++++++++++++++++++++--
 1 files changed, 26 insertions(+), 2 deletions(-)
---
diff --git a/backends/c/service.py b/backends/c/service.py
index 11401fc..82f0bd3 100644
--- a/backends/c/service.py
+++ b/backends/c/service.py
@@ -24,6 +24,25 @@ import glob, os, subprocess
 _did_libclang_config = False
 _global_sysinclude = None
 
+class UnsavedFile(object):
+    def __init__(self, *args, **kwargs):
+        self._file = open(*args, **kwargs)
+
+    def close(self, do_close=False):
+        if do_close:
+            self._file.close()
+        else:
+            self._file.seek(0)
+
+    def read(self, *args, **kwargs):
+        return self._file.read(*args, **kwargs)
+
+    def tell(self):
+        return self._file.tell()
+
+    def seek(self, *args, **kwargs):
+        return self._file.seek(*args, **kwargs)
+
 def config_libclang():
     global _did_libclang_config
     global _global_sysinclude
@@ -168,11 +187,16 @@ class Service(transport.Service, transport.Project,
 
     def complete(self, doc, options):
         if doc.data_path != doc.path:
-            unsaved = [(doc.path, open(doc.data_path, 'rb'))]
+            unsaved = [(doc.path, UnsavedFile(doc.data_path, 'rb'))]
         else:
             unsaved = []
 
-        self._complete(doc, [doc], unsaved, options)
+        ret = self._complete(doc, [doc], unsaved, options)
+
+        for (_,f) in unsaved:
+            f.close(do_close=True)
+
+        return ret
 
     def _included_docs(self, doc, docmap):
         includes = doc.tu.get_includes()