Split WipeData into PreWipeData and PostWipeData.

Bug: http://b/21760064
Change-Id: Idde268fe4d7e27586ca4469de16783f1ffdc5069
diff --git a/device.h b/device.h
index dad8ccd..f74b6b0 100644
--- a/device.h
+++ b/device.h
@@ -91,13 +91,16 @@
     static const int kHighlightDown = -3;
     static const int kInvokeItem = -4;
 
-    // Called when we do a wipe data/factory reset operation (either via a
-    // reboot from the main system with the --wipe_data flag, or when the
-    // user boots into recovery manually and selects the option from the
-    // menu.)  Can perform whatever device-specific wiping actions are
-    // needed.  Return 0 on success.  The userdata and cache partitions
-    // are erased AFTER this returns (whether it returns success or not).
-    virtual int WipeData() { return 0; }
+    // Called before and after we do a wipe data/factory reset operation,
+    // either via a reboot from the main system with the --wipe_data flag,
+    // or when the user boots into recovery image manually and selects the
+    // option from the menu, to perform whatever device-specific wiping
+    // actions are needed.
+    // Return true on success; returning false from PreWipeData will prevent
+    // the regular wipe, and returning false from PostWipeData will cause
+    // the wipe to be considered a failure.
+    virtual bool PreWipeData() { return true; }
+    virtual bool PostWipeData() { return true; }
 
   private:
     RecoveryUI* ui_;
diff --git a/recovery.cpp b/recovery.cpp
index 76149cd..6cda10c 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -421,8 +421,7 @@
     struct _saved_log_file* next;
 } saved_log_file;
 
-static int
-erase_volume(const char *volume) {
+static bool erase_volume(const char* volume) {
     bool is_cache = (strcmp(volume, CACHE_ROOT) == 0);
 
     ui->SetBackground(RecoveryUI::ERASING);
@@ -503,7 +502,7 @@
         copy_logs();
     }
 
-    return result;
+    return (result == 0);
 }
 
 static int
@@ -677,13 +676,13 @@
     modified_flash = true;
 
     ui->Print("\n-- Wiping data...\n");
-    if (device->WipeData() == 0 && erase_volume("/data") == 0 && erase_volume("/cache") == 0) {
-        ui->Print("Data wipe complete.\n");
-        return true;
-    } else {
-        ui->Print("Data wipe failed.\n");
-        return false;
-    }
+    bool success =
+        device->PreWipeData() &&
+        erase_volume("/data") &&
+        erase_volume("/cache") &&
+        device->PostWipeData();
+    ui->Print("Data wipe %s.\n", success ? "complete" : "failed");
+    return success;
 }
 
 // Return true on success.
@@ -695,13 +694,9 @@
     modified_flash = true;
 
     ui->Print("\n-- Wiping cache...\n");
-    if (erase_volume("/cache") == 0) {
-        ui->Print("Cache wipe complete.\n");
-        return true;
-    } else {
-        ui->Print("Cache wipe failed.\n");
-        return false;
-    }
+    bool success = erase_volume("/cache");
+    ui->Print("Cache wipe %s.\n", success ? "complete" : "failed");
+    return success;
 }
 
 static void choose_recovery_file(Device* device) {