oc: Implement Sharing Message Object

It acts as a proxy of MAPIStoreMailMessage and it manages the properties
defined in [MS-OXSHARE] Section 2.2 by storing them in the mail message
as eXtensible MIME headers which starts with X-MS-Sharing.

OpenChange/MAPIStoreMailMessage.m

@@ -51,6 +51,7 @@
 #import "MAPIStoreMailFolder.h"
 #import "MAPIStoreMapping.h"
 #import "MAPIStoreSamDBUtils.h"
+#import "MAPIStoreSharingMessage.h"
 #import "MAPIStoreTypes.h"
 #import "MAPIStoreUserContext.h"
 
@@ -115,6 +116,7 @@ static Class NSExceptionK;
     {
       mimeKey = nil;
       mailIsEvent = NO;
+      mailIsSharingObject = NO;
       headerCharset = nil;
       headerEncoding = nil;
       headerMimeType = nil;
@@ -201,9 +203,11 @@ _compareBodyKeysByPriority (id entry1, id entry2, void *data)
 
 - (void) _fetchHeaderData
 {
+  MAPIStoreSharingMessage *sharingMessage;
   NSMutableArray *keys;
   NSArray *acceptedTypes;
   NSDictionary *messageData, *partHeaderData, *parameters;
+  NSString *sharingHeader;
 
   acceptedTypes = [NSArray arrayWithObjects: @"text/calendar",
                            @"application/ics",
@@ -228,6 +232,21 @@ _compareBodyKeysByPriority (id entry1, id entry2, void *data)
       if ([headerMimeType isEqualToString: @"text/calendar"]
           || [headerMimeType isEqualToString: @"application/ics"])
         mailIsEvent = YES;
+      else
+        {
+          sharingHeader = [[sogoObject mailHeaders] objectForKey: @"x-ms-sharing-localtype"];
+          if (sharingHeader)
+            {
+              mailIsSharingObject = YES;
+              /* It is difficult to subclass this in folder class, that's why
+                 a sharing object is a proxy in a mail message */
+              sharingMessage = [[MAPIStoreSharingMessage alloc]
+                                 initWithMailHeaders: [sogoObject mailHeaders]
+                                   andConnectionInfo: [[self context] connectionInfo]];
+              [self addProxy: sharingMessage];
+              [sharingMessage release];
+            }
+        }
     }
 
   headerSetup = YES;
@@ -517,6 +536,8 @@ _compareBodyKeysByPriority (id entry1, id entry2, void *data)
   if (mailIsEvent)
     [[self _appointmentWrapper] getPidTagMessageClass: data
                                              inMemCtx: memCtx];
+  else if (mailIsSharingObject)
+    *data = talloc_strdup (memCtx, "IPM.Sharing");
   else
     *data = talloc_strdup (memCtx, "IPM.Note");