Add possibility of fetching message attachment by chunks and store it to file. (#1438)

5 files changed, 203 insertions, 0 deletions

diff --git a/src/objc/imap/MCOIMAP.h b/src/objc/imap/MCOIMAP.h
index 11cbc2ae..4de8f18e 100644
--- a/src/objc/imap/MCOIMAP.h
+++ b/src/objc/imap/MCOIMAP.h
@@ -30,6 +30,7 @@
 #import <MailCore/MCOIMAPMoveMessagesOperation.h>
 #import <MailCore/MCOIMAPFetchMessagesOperation.h>
 #import <MailCore/MCOIMAPFetchContentOperation.h>
+#import <MailCore/MCOIMAPFetchContentToFileOperation.h>
 #import <MailCore/MCOIMAPFetchParsedContentOperation.h>
 #import <MailCore/MCOIMAPSearchOperation.h>
 #import <MailCore/MCOIMAPIdleOperation.h>
diff --git a/src/objc/imap/MCOIMAPFetchContentToFileOperation.h b/src/objc/imap/MCOIMAPFetchContentToFileOperation.h
new file mode 100644
index 00000000..4d06e94d
--- /dev/null
+++ b/src/objc/imap/MCOIMAPFetchContentToFileOperation.h
@@ -0,0 +1,51 @@
+//
+//  MCOIMAPFetchContentToFileOperation.h
+//  mailcore2
+//
+//  Created by Dmitry Isaikin on 2/08/16.
+//  Copyright (c) 2016 MailCore. All rights reserved.
+//
+
+#ifndef MAILCORE_MCOIMAPFETCHCONTENTTOFILEOPERATION_H
+
+#define MAILCORE_MCOIMAPFETCHCONTENTTOFILEOPERATION_H
+
+/** 
+ This class implements an operation to fetch the content of a message to the file.
+ It can be a part or a full message.
+*/
+
+#import <MailCore/MCOIMAPBaseOperation.h>
+#import <MailCore/MCOConstants.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MCOIMAPFetchContentToFileOperation : MCOIMAPBaseOperation
+
+/** 
+ This block will be called as bytes are received from the network
+*/
+@property (nonatomic, copy, nullable) MCOIMAPBaseOperationProgressBlock progress;
+
+@property (nonatomic, assign, getter=isLoadingByChunksEnabled) BOOL loadingByChunksEnabled;
+@property (nonatomic, assign) uint32_t chunksSize;
+@property (nonatomic, assign) uint32_t estimatedSize;
+
+/** 
+ Starts the asynchronous fetch operation.
+
+ @param completionBlock Called when the operation is finished.
+
+ - On success `error` will be nil
+ 
+ - On failure, `error` will be set with `MCOErrorDomain` as domain and an 
+   error code available in `MCOConstants.h`
+*/
+
+- (void) start:(void (^)(NSError * __nullable error))completionBlock;
+
+@end
+
+NS_ASSUME_NONNULL_END
+
+#endif
diff --git a/src/objc/imap/MCOIMAPFetchContentToFileOperation.mm b/src/objc/imap/MCOIMAPFetchContentToFileOperation.mm
new file mode 100644
index 00000000..4f2bbfcf
--- /dev/null
+++ b/src/objc/imap/MCOIMAPFetchContentToFileOperation.mm
@@ -0,0 +1,103 @@
+//
+//  MCOIMAPFetchContentToFileOperation.mm
+//  mailcore2
+//
+//  Created by Dmitry Isaikin on 2/08/16.
+//  Copyright (c) 2016 MailCore. All rights reserved.
+//
+
+#import "MCOIMAPFetchContentToFileOperation.h"
+
+#include "MCAsyncIMAP.h"
+
+#import "MCOOperation+Private.h"
+#import "MCOUtils.h"
+
+typedef void (^CompletionType)(NSError *error);
+
+@implementation MCOIMAPFetchContentToFileOperation {
+    CompletionType _completionBlock;
+    MCOIMAPBaseOperationProgressBlock _progress;
+}
+
+@synthesize progress = _progress;
+
+#define nativeType mailcore::IMAPFetchContentToFileOperation
+
++ (void) load
+{
+    MCORegisterClass(self, &typeid(nativeType));
+}
+
++ (NSObject *) mco_objectWithMCObject:(mailcore::Object *)object
+{
+    nativeType * op = (nativeType *) object;
+    return [[[self alloc] initWithMCOperation:op] autorelease];
+}
+
+- (void)setLoadingByChunksEnabled:(BOOL)loadingByChunksEnabled {
+    MCO_NATIVE_INSTANCE->setLoadingByChunksEnabled(loadingByChunksEnabled);
+}
+
+- (BOOL)isLoadingByChunksEnabled {
+    return MCO_NATIVE_INSTANCE->isLoadingByChunksEnabled();
+}
+
+- (void)setChunksSize:(uint32_t)chunksSize {
+    MCO_NATIVE_INSTANCE->setChunksSize(chunksSize);
+}
+
+- (uint32_t)chunksSize {
+    return MCO_NATIVE_INSTANCE->chunksSize();
+}
+
+- (void)setEstimatedSize:(uint32_t)estimatedSize {
+    MCO_NATIVE_INSTANCE->setEstimatedSize(estimatedSize);
+}
+
+- (uint32_t)estimatedSize {
+    return MCO_NATIVE_INSTANCE->estimatedSize();
+}
+
+- (void) dealloc
+{
+    [_progress release];
+    [_completionBlock release];
+    [super dealloc];
+}
+
+- (void) start:(void (^)(NSError *error))completionBlock {
+    _completionBlock = [completionBlock copy];
+    [self start];
+}
+
+- (void) cancel
+{
+    [_completionBlock release];
+    _completionBlock = nil;
+    [super cancel];
+}
+
+- (void) operationCompleted
+{
+    if (_completionBlock == NULL)
+        return;
+
+    nativeType *op = MCO_NATIVE_INSTANCE;
+    if (op->error() == mailcore::ErrorNone) {
+        _completionBlock(nil);
+    } else {
+        _completionBlock([NSError mco_errorWithErrorCode:op->error()]);
+    }
+    [_completionBlock release];
+    _completionBlock = nil;
+}
+
+- (void) bodyProgress:(unsigned int)current maximum:(unsigned int)maximum
+{
+    if (_progress != NULL) {
+        _progress(current, maximum);
+    }
+}
+
+@end
diff --git a/src/objc/imap/MCOIMAPSession.h b/src/objc/imap/MCOIMAPSession.h
index 7674e9db..12a1e651 100644
--- a/src/objc/imap/MCOIMAPSession.h
+++ b/src/objc/imap/MCOIMAPSession.h
@@ -24,6 +24,7 @@
 @class MCOIndexSet;
 @class MCOIMAPFetchMessagesOperation;
 @class MCOIMAPFetchContentOperation;
+@class MCOIMAPFetchContentToFileOperation;
 @class MCOIMAPFetchParsedContentOperation;
 @class MCOIMAPSearchOperation;
 @class MCOIMAPIdleOperation;
@@ -848,6 +849,37 @@ vanishedMessages will be set only for servers that support QRESYNC. See [RFC5162
                                                                       partID:(NSString *)partID
                                                                     encoding:(MCOEncoding)encoding;
 
+/**
+ Returns an operation to fetch an attachment to a file.
+ @param  urgent is set to YES, an additional connection to the same folder might be opened to fetch the content.
+ Operation will be perform in a memory efficient manner.
+
+     MCOIMAPFetchContentToFileOperation * op = [session fetchMessageAttachmentToFileOperationWithFolder:@"INBOX"
+                                                                                                    uid:456
+                                                                                                 partID:@"1.2"
+                                                                                               encoding:MCOEncodingBase64
+                                                                                               filename:filename
+                                                                                                 urgent:YES];
+
+     // Optionally, explicitly enable chunked mode
+     [op setLoadingByChunksEnabled:YES];
+     [op setChunksSize:1024*1024];
+     // need in chunked mode for correct progress indication
+     [op setEstimatedSize:sizeOfAttachFromBodystructure];
+
+     [op start:^(NSError * __nullable error) {
+         ...
+     }];
+
+ */
+- (MCOIMAPFetchContentToFileOperation *) fetchMessageAttachmentToFileOperationWithFolder:(NSString *)folder
+                                                                                     uid:(uint32_t)uid
+                                                                                  partID:(NSString *)partID
+                                                                                encoding:(MCOEncoding)encoding
+                                                                                filename:(NSString *)filename
+                                                                                  urgent:(BOOL)urgent;
+
+
 /** @name General IMAP Actions */
 
 /**
diff --git a/src/objc/imap/MCOIMAPSession.mm b/src/objc/imap/MCOIMAPSession.mm
index 2eba5cc0..94a3020b 100644
--- a/src/objc/imap/MCOIMAPSession.mm
+++ b/src/objc/imap/MCOIMAPSession.mm
@@ -498,6 +498,22 @@ MCO_OBJC_SYNTHESIZE_SCALAR(dispatch_queue_t, dispatch_queue_t, setDispatchQueue,
     return [self fetchMessageAttachmentOperationWithFolder:folder number:number partID:partID encoding:encoding urgent:NO];
 }
 
+- (MCOIMAPFetchContentToFileOperation *) fetchMessageAttachmentToFileOperationWithFolder:(NSString *)folder
+                                                                                     uid:(uint32_t)uid
+                                                                                  partID:(NSString *)partID
+                                                                                encoding:(MCOEncoding)encoding
+                                                                                filename:(NSString *)filename
+                                                                                  urgent:(BOOL)urgent
+{
+    IMAPFetchContentToFileOperation * coreOp = MCO_NATIVE_INSTANCE->fetchMessageAttachmentToFileByUIDOperation([folder mco_mcString],
+                                                                                                               uid,
+                                                                                                               [partID mco_mcString],
+                                                                                                               (Encoding) encoding,
+                                                                                                               [filename mco_mcString],
+                                                                                                               urgent);
+    return MCO_TO_OBJC_OP(coreOp);
+}
+
 - (MCOIMAPOperation *) storeFlagsOperationWithFolder:(NSString *)folder
                                                 uids:(MCOIndexSet *)uids
                                                 kind:(MCOIMAPStoreFlagsRequestKind)kind