From 47f0eafe9ab2b979690763a639d07bee392ec258 Mon Sep 17 00:00:00 2001
From: Thomas Rehn <thomas.rehn@initos.com>
Date: Thu, 25 Aug 2016 08:02:46 +0200
Subject: [PATCH] [IMP] rewrite get_binary_extension so that it uses a first
 pass to determine the extension from the filename only

---
 attachment_preview/__openerp__.py         |  2 +-
 attachment_preview/model/ir_attachment.py | 68 +++++++++++++----------
 2 files changed, 40 insertions(+), 30 deletions(-)

diff --git a/attachment_preview/__openerp__.py b/attachment_preview/__openerp__.py
index fa62e146..62eda094 100644
--- a/attachment_preview/__openerp__.py
+++ b/attachment_preview/__openerp__.py
@@ -20,7 +20,7 @@
 ##############################################################################
 {
     "name": "Preview attachments",
-    "version": "8.0.1.1.0",
+    "version": "8.0.1.2.0",
     "author": "Therp BV,Odoo Community Association (OCA)",
     "license": "AGPL-3",
     "complexity": "normal",
diff --git a/attachment_preview/model/ir_attachment.py b/attachment_preview/model/ir_attachment.py
index b00d3474..da8c86d7 100644
--- a/attachment_preview/model/ir_attachment.py
+++ b/attachment_preview/model/ir_attachment.py
@@ -32,35 +32,45 @@ class IrAttachment(Model):
             self, cr, uid, model, ids, binary_field, filename_field=None,
             context=None):
         result = {}
-        for this in self.pool[model].browse(
-                cr, uid,
-                ids if isinstance(ids, collections.Iterable) else [ids],
-                context=context):
-            if not this.id:
-                result[this.id] = False
-                continue
-            extension = ''
-            if filename_field and this[filename_field]:
-                filename, extension = os.path.splitext(this[filename_field])
-            if not this[binary_field]:
-                result[this.id] = False
-                continue
-            if not extension:
-                try:
-                    import magic
-                    ms = magic.open(
-                        hasattr(magic, 'MAGIC_MIME_TYPE') and
-                        magic.MAGIC_MIME_TYPE or magic.MAGIC_MIME)
-                    ms.load()
-                    mimetype = ms.buffer(
-                        base64.b64decode(this[binary_field]))
-                except ImportError:
-                    (mimetype, encoding) = mimetypes.guess_type(
-                        'data:;base64,' + this[binary_field], strict=False)
-                extension = mimetypes.guess_extension(
-                    mimetype.split(';')[0], strict=False)
-
-            result[this.id] = (extension or '').lstrip('.').lower()
+        context_bin_size = dict(context or {})
+        context_bin_size['bin_size'] = True
+        ids_to_browse = ids if isinstance(ids, collections.Iterable) \
+            else [ids]
+        # First pass: load fields in bin_size mode to avoid loading big files
+        #  unnecessarily.
+        if filename_field:
+            for this in self.pool[model].browse(cr, uid, ids_to_browse,
+                                                context=context_bin_size):
+                if not this.id:
+                    result[this.id] = False
+                    continue
+                extension = ''
+                if this[filename_field]:
+                    filename, extension = os.path.splitext(
+                        this[filename_field])
+                if this[binary_field] and extension:
+                    result[this.id] = extension
+        # Second pass for all attachments which have to be loaded fully
+        #  to get the extension from the content
+        ids_to_browse = [_id for _id in ids_to_browse if _id not in result]
+        for this in self.pool[model].browse(cr, uid, ids_to_browse,
+                                            context=context):
+            try:
+                import magic
+                ms = magic.open(
+                    hasattr(magic, 'MAGIC_MIME_TYPE') and
+                    magic.MAGIC_MIME_TYPE or magic.MAGIC_MIME)
+                ms.load()
+                mimetype = ms.buffer(
+                    base64.b64decode(this[binary_field]))
+            except ImportError:
+                (mimetype, encoding) = mimetypes.guess_type(
+                    'data:;base64,' + this[binary_field], strict=False)
+            extension = mimetypes.guess_extension(
+                mimetype.split(';')[0], strict=False)
+            result[this.id] = extension
+        for _id in result:
+            result[_id] = (extension or '').lstrip('.').lower()
         return result if isinstance(ids, collections.Iterable) else result[ids]
 
     def get_attachment_extension(self, cr, uid, ids, context=None):