Add containsString polyfill for IOS7 #119

src/ios/IOS7Polyfill.h

+//
+//  IOS7Polyfill.h
+//  RNFetchBlob
+//
+//  Created by Ben Hsieh on 2016/9/6.
+//  Copyright © 2016年 wkh237.github.io. All rights reserved.
+//
+
+#ifndef IOS7Polyfill_h
+#define IOS7Polyfill_h
+
+@implementation NSString (Contains)
+
+- (BOOL)RNFBContainsString:(NSString*)other {
+    NSRange range = [self rangeOfString:other];
+    return range.length != 0;
+}
+
+
+@end
+#endif /* IOS7Polyfill_h */

src/ios/RNFetchBlob.xcodeproj/project.pbxproj

 		A15C30131CD25C330074CB35 /* RNFetchBlob.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = RNFetchBlob.m; path = RNFetchBlob/RNFetchBlob.m; sourceTree = "<group>"; };
 		A1AAE2971D300E3E0051D11C /* RNFetchBlobReqBuilder.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RNFetchBlobReqBuilder.h; sourceTree = "<group>"; };
 		A1AAE2981D300E4D0051D11C /* RNFetchBlobReqBuilder.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RNFetchBlobReqBuilder.m; sourceTree = "<group>"; };
+		A1F950181D7E9134002A95A6 /* IOS7Polyfill.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = IOS7Polyfill.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
 		A15C30051CD25C330074CB35 = {
 			isa = PBXGroup;
 			children = (
+				A1F950181D7E9134002A95A6 /* IOS7Polyfill.h */,
 				A1AAE2981D300E4D0051D11C /* RNFetchBlobReqBuilder.m */,
 				A1AAE2971D300E3E0051D11C /* RNFetchBlobReqBuilder.h */,
 				A158F42F1D0539DB006FFD38 /* RNFetchBlobNetwork.m */,

src/ios/RNFetchBlobFS.m

 #import "RCTEventDispatcher.h"
 #import "RNFetchBlobFS.h"
 #import "RNFetchBlobConst.h"
+#import "IOS7Polyfill.h"
 @import AssetsLibrary;
 
 
         int read = 0;
         int chunkSize = bufferSize;
         // allocate buffer in heap instead of stack
-        uint8_t * buffer = (uint8_t *) malloc(bufferSize);
+        uint8_t * buffer;
         @try
         {
+            buffer = (uint8_t *) malloc(bufferSize);
             if(path != nil)
             {
                 if([[NSFileManager defaultManager] fileExistsAtPath:path] == NO)
                 NSDictionary * payload = @{ @"event": FS_EVENT_ERROR, @"detail": @"RNFetchBlob.readStream unable to resolve URI" };
                 [event sendDeviceEventWithName:streamId body:payload];
             }
+            // release buffer
+            if(buffer != nil)
+                free(buffer);
             
         }
         @catch (NSError * err)
         }
         @finally
         {
-            // release buffer
-            free(buffer);
             NSDictionary * payload = @{ @"event": FS_EVENT_END, @"detail": @"" };
             [event sendDeviceEventWithName:streamId body:payload];
         }
         }
         NSFileHandle *fileHandle = [NSFileHandle fileHandleForWritingAtPath:path];
         NSData * content = nil;
-        if([encoding containsString:@"base64"]) {
+        if([encoding RNFBContainsString:@"base64"]) {
             content = [[NSData alloc] initWithBase64EncodedString:data options:0];
         }
         else if([encoding isEqualToString:@"uri"]) {

src/ios/RNFetchBlobNetwork.m

 #import "RNFetchBlobNetwork.h"
 #import "RNFetchBlobConst.h"
 #import "RNFetchBlobReqBuilder.h"
+#import "IOS7Polyfill.h"
 #import <CommonCrypto/CommonDigest.h>
 
 ////////////////////////////////////////
         if(respCType != nil)
         {
             NSArray * extraBlobCTypes = [options objectForKey:CONFIG_EXTRA_BLOB_CTYPE];
-            if([respCType containsString:@"text/"])
+            if([respCType RNFBContainsString:@"text/"])
             {
                 respType = @"text";
             }
-            else if([respCType containsString:@"application/json"])
+            else if([respCType RNFBContainsString:@"application/json"])
             {
                 respType = @"json";
             }
             else if( extraBlobCTypes !=  nil) {
                 for(NSString * substr in extraBlobCTypes)
                 {
-                    if([respCType containsString:[substr lowercaseString]])
+                    if([respCType RNFBContainsString:[substr lowercaseString]])
                     {
                         respType = @"blob";
                         respFile = YES;

src/ios/RNFetchBlobReqBuilder.m

 #import "RNFetchBlobConst.h"
 #import "RNFetchBlobFS.h"
 #import "RCTLog.h"
+#import "IOS7Polyfill.h"
 
 @interface RNFetchBlobReqBuilder()
 {
                     
                     __block NSString * cType = [[self class]getHeaderIgnoreCases:@"content-type" fromHeaders:mheaders];
                     // when content-type is application/octet* decode body string using BASE64 decoder
-                    if([[cType lowercaseString] hasPrefix:@"application/octet"] || [[cType lowercaseString] containsString:@";base64"])
+                    if([[cType lowercaseString] hasPrefix:@"application/octet"] || [[cType lowercaseString] RNFBContainsString:@";base64"])
                     {
                         __block NSString * ncType = [[cType stringByReplacingOccurrencesOfString:@";base64" withString:@""]stringByReplacingOccurrencesOfString:@";BASE64" withString:@""];
                         if([mheaders valueForKey:@"content-type"] != nil)