Bug 1356693 - infer: fix RESOURCE_LEAK's in services r=Grisha

The primary issue is that we use a throwing InputStreamReader
constructor. If it throws, then any nested streams will be lost.
We can fix that by using the non-throwing InputStreamReader
constructor (which uses a Charset as the second parameter,
instead of a String which causes an Exception to be thrown
if it can't be parsed)

We also simplify some nested Stream's a little: most of the
Stream constructors don't throw, so there's no harm in not keeping
individual references to those that don't throw - and that
results in less Stream references for us to handle.

MozReview-Commit-ID: 2hyRFGVmGnU

--HG--
extra : rebase_source : 15dd97d28012a017326b01ae8ddc370c7f1ec484

mobile/android/services/src/main/java/org/mozilla/gecko/sync/Utils.java

@@ -31,6 +31,7 @@ import org.mozilla.apache.commons.codec.binary.Base64;
 import org.mozilla.gecko.background.common.log.Logger;
 import org.mozilla.gecko.background.nativecode.NativeCrypto;
 import org.mozilla.gecko.sync.setup.Constants;
+import org.mozilla.gecko.util.IOUtils;
 import org.mozilla.gecko.util.StringUtils;
 
 import android.content.Context;
@@ -488,14 +489,10 @@ public class Utils {
       throw new IllegalArgumentException("Passed null filename in readFile.");
     }
 
-    FileInputStream fis = null;
-    InputStreamReader isr = null;
     BufferedReader br = null;
 
     try {
-      fis = context.openFileInput(filename);
-      isr = new InputStreamReader(fis, StringUtils.UTF_8);
-      br = new BufferedReader(isr);
+      br = new BufferedReader(new InputStreamReader(context.openFileInput(filename), StringUtils.UTF_8));
       StringBuilder sb = new StringBuilder();
       String line;
       while ((line = br.readLine()) != null) {
@@ -505,20 +502,7 @@ public class Utils {
     } catch (Exception e) {
       return null;
     } finally {
-      if (isr != null) {
-        try {
-          isr.close();
-        } catch (IOException e) {
-          // Ignore.
-        }
-      }
-      if (fis != null) {
-        try {
-          fis.close();
-        } catch (IOException e) {
-          // Ignore.
-        }
-      }
+      IOUtils.safeStreamClose(br);
     }
   }
 

mobile/android/services/src/main/java/org/mozilla/gecko/sync/net/MozResponse.java

@@ -18,6 +18,7 @@ import org.mozilla.gecko.background.common.log.Logger;
 import org.mozilla.gecko.sync.ExtendedJSONObject;
 import org.mozilla.gecko.sync.NonArrayJSONException;
 import org.mozilla.gecko.sync.NonObjectJSONException;
+import org.mozilla.gecko.util.IOUtils;
 import org.mozilla.gecko.util.StringUtils;
 
 import ch.boye.httpclientandroidlib.Header;
@@ -106,12 +107,12 @@ public class MozResponse {
       throw new IOException("no entity");
     }
 
-    InputStream content = entity.getContent();
+    Reader in = null;
     try {
-      Reader in = new BufferedReader(new InputStreamReader(content, "UTF-8"));
+      in = new BufferedReader(new InputStreamReader(entity.getContent(), StringUtils.UTF_8));
       return new ExtendedJSONObject(in);
     } finally {
-      content.close();
+      IOUtils.safeStreamClose(in);
     }
   }