1. clearCache is now called right after memory warning notification h…

…as been send. A note about this is added to the .h

2. Tests are added.
2.1 checking that clearCache calls are safe, while there is a recognition is in process. A note about this is also added to .h
2.2 checking that clearCache is automatically called on UIApplicationDidReceiveMemoryWarningNotification

TesseractOCR/G8Tesseract.h

@@ -28,7 +28,8 @@
  *  Clear any library-level memory caches.
  *  There are a variety of expensive-to-load constant data structures (mostly
  *  language dictionaries) that are cached globally. This function allows the
- *  clearing of these caches.
+ *  clearing of these caches. It's safe to call this method, while a recognition is in progress.
+ *  It's also called automatically on UIApplicationDidReceiveMemoryWarningNotification
  */
 + (void)clearCache;
 

TesseractOCR/G8Tesseract.mm

@@ -51,6 +51,22 @@ @implementation G8Tesseract
 
 @synthesize absoluteDataPath=_absoluteDataPath;
 
++ (void)initialize {
+
+    [super initialize];
+
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(didReceiveMemoryWarningNotification:)
+                                                 name:UIApplicationDidReceiveMemoryWarningNotification
+                                               object:nil];
+}
+
++ (void)didReceiveMemoryWarningNotification:(NSNotification*)notification {
+
+    [self clearCache];
+    // some more cleaning here if necessary
+}
+
 + (NSString *)version
 {
     const char *version = tesseract::TessBaseAPI::Version();

TestsProject/TestsProjectTests/InitializationTests.m

@@ -13,6 +13,7 @@
 #import "Defaults.h"
 
 @interface G8Tesseract (Tests)
++ (void)didReceiveMemoryWarningNotification:(NSNotification*)notification;
 - (BOOL)configEngine;
 - (BOOL)resetEngine;
 @end
@@ -53,6 +54,26 @@ - (BOOL)resetEngine;
         it(@"Should check version", ^{
             [[[G8Tesseract version] should] equal:@"3.03"];
         });
+
+        it(@"Should clear cache", ^{
+            // while recognition is in progress
+            for (int i = 0; i <= 10; i++) {
+                G8RecognitionOperation *operation = [[G8RecognitionOperation alloc] init];
+                operation.tesseract.image = [UIImage imageNamed:@"well_scaned_page"];
+                operation.tesseract.language = kG8Languages;
+
+                NSOperationQueue *queue = [[NSOperationQueue alloc] init];
+                [queue addOperation:operation];
+            }
+
+            [[theBlock(^{
+                [G8Tesseract clearCache];
+            }) shouldNot] raise];
+
+            // should be called on a memory warning notification
+            [[G8Tesseract should] receive:@selector(didReceiveMemoryWarningNotification:)];
+            [[NSNotificationCenter defaultCenter] postNotificationName:UIApplicationDidReceiveMemoryWarningNotification object:nil];
+        });
     });
 
     context(@"nil cachesRelatedDataPath", ^{