RecoverySnapshotStorage: fold readFromDisk() and writeFromDisk() into callers

readFromDisk() and writeFromDisk() each have only one caller, get() and
put() respectively.  Fold them into these callers to make the code more
straightforward.  No change in behavior.

Flag: EXEMPT refactor
Bug: 372499066
Test: atest FrameworksServicesTests:com.android.server.locksettings.recoverablekeystore
Change-Id: I11aa7bac563fe9c87bcf3d17cec02db5ead869c9
diff --git a/services/core/java/com/android/server/locksettings/recoverablekeystore/storage/RecoverySnapshotStorage.java b/services/core/java/com/android/server/locksettings/recoverablekeystore/storage/RecoverySnapshotStorage.java
index c02b103..7158e349 100644
--- a/services/core/java/com/android/server/locksettings/recoverablekeystore/storage/RecoverySnapshotStorage.java
+++ b/services/core/java/com/android/server/locksettings/recoverablekeystore/storage/RecoverySnapshotStorage.java
@@ -81,9 +81,13 @@
     public synchronized void put(int uid, KeyChainSnapshot snapshot) {
         mSnapshotByUid.put(uid, snapshot);
 
-        try {
-            writeToDisk(uid, snapshot);
+        File snapshotFile = getSnapshotFile(uid);
+        try (FileOutputStream fileOutputStream = new FileOutputStream(snapshotFile)) {
+            KeyChainSnapshotSerializer.serialize(snapshot, fileOutputStream);
         } catch (IOException | CertificateEncodingException e) {
+            // If we fail to write the latest snapshot, we should delete any older snapshot that
+            // happens to be around. Otherwise snapshot syncs might end up going 'back in time'.
+            snapshotFile.delete();
             Log.e(TAG,
                     String.format(Locale.US, "Error persisting snapshot for %d to disk", uid),
                     e);
@@ -100,9 +104,13 @@
             return snapshot;
         }
 
-        try {
-            return readFromDisk(uid);
+        File snapshotFile = getSnapshotFile(uid);
+        try (FileInputStream fileInputStream = new FileInputStream(snapshotFile)) {
+            return KeyChainSnapshotDeserializer.deserialize(fileInputStream);
         } catch (IOException | KeyChainSnapshotParserException e) {
+            // If we fail to read the latest snapshot, we should delete it in case it is in some way
+            // corrupted. We can regenerate snapshots anyway.
+            snapshotFile.delete();
             Log.e(TAG, String.format(Locale.US, "Error reading snapshot for %d from disk", uid), e);
             return null;
         }
@@ -116,50 +124,6 @@
         getSnapshotFile(uid).delete();
     }
 
-    /**
-     * Writes the snapshot for recovery agent {@code uid} to disk.
-     *
-     * @throws IOException if an IO error occurs writing to disk.
-     */
-    private void writeToDisk(int uid, KeyChainSnapshot snapshot)
-            throws IOException, CertificateEncodingException {
-        File snapshotFile = getSnapshotFile(uid);
-
-        try (
-            FileOutputStream fileOutputStream = new FileOutputStream(snapshotFile)
-        ) {
-            KeyChainSnapshotSerializer.serialize(snapshot, fileOutputStream);
-        } catch (IOException | CertificateEncodingException e) {
-            // If we fail to write the latest snapshot, we should delete any older snapshot that
-            // happens to be around. Otherwise snapshot syncs might end up going 'back in time'.
-            snapshotFile.delete();
-            throw e;
-        }
-    }
-
-    /**
-     * Reads the last snapshot for recovery agent {@code uid} from disk.
-     *
-     * @return The snapshot, or null if none existed.
-     * @throws IOException if an IO error occurs reading from disk.
-     */
-    @Nullable
-    private KeyChainSnapshot readFromDisk(int uid)
-            throws IOException, KeyChainSnapshotParserException {
-        File snapshotFile = getSnapshotFile(uid);
-
-        try (
-            FileInputStream fileInputStream = new FileInputStream(snapshotFile)
-        ) {
-            return KeyChainSnapshotDeserializer.deserialize(fileInputStream);
-        } catch (IOException | KeyChainSnapshotParserException e) {
-            // If we fail to read the latest snapshot, we should delete it in case it is in some way
-            // corrupted. We can regenerate snapshots anyway.
-            snapshotFile.delete();
-            throw e;
-        }
-    }
-
     private File getSnapshotFile(int uid) {
         File folder = getStorageFolder();
         String fileName = getSnapshotFileName(uid);