Guide user towards adoption when card is "empty".

When a newly inserted SD card is empty, we'd like to guide the user
towards adopting it.  Similarly, if the card contains personal media
like photos, we'd like to guide the user towards using it as portable
storage.

Do this by quickly hunting around on the card for files under various
well-known directories.  Special logic to ignore bundled "helper"
apps included from the SD card factory.

Test: bit FrameworksCoreTests:android.os.EnvironmentTest
Bug: 69128181
Change-Id: I10e43d2e76379fac5137eb3810742c33f5f57d80

1 files changed, 74 insertions, 0 deletions

diff --git a/core/java/android/os/Environment.java b/core/java/android/os/Environment.java
index f977c1dea438..ce82062c56f0 100644
--- a/core/java/android/os/Environment.java
+++ b/core/java/android/os/Environment.java
@@ -24,6 +24,7 @@ import android.text.TextUtils;
 import android.util.Log;
 
 import java.io.File;
+import java.util.LinkedList;
 
 /**
  * Provides access to environment variables.
@@ -608,6 +609,79 @@ public class Environment {
         return false;
     }
 
+    /** {@hide} */ public static final int HAS_MUSIC = 1 << 0;
+    /** {@hide} */ public static final int HAS_PODCASTS = 1 << 1;
+    /** {@hide} */ public static final int HAS_RINGTONES = 1 << 2;
+    /** {@hide} */ public static final int HAS_ALARMS = 1 << 3;
+    /** {@hide} */ public static final int HAS_NOTIFICATIONS = 1 << 4;
+    /** {@hide} */ public static final int HAS_PICTURES = 1 << 5;
+    /** {@hide} */ public static final int HAS_MOVIES = 1 << 6;
+    /** {@hide} */ public static final int HAS_DOWNLOADS = 1 << 7;
+    /** {@hide} */ public static final int HAS_DCIM = 1 << 8;
+    /** {@hide} */ public static final int HAS_DOCUMENTS = 1 << 9;
+
+    /** {@hide} */ public static final int HAS_ANDROID = 1 << 16;
+    /** {@hide} */ public static final int HAS_OTHER = 1 << 17;
+
+    /**
+     * Classify the content types present on the given external storage device.
+     * <p>
+     * This is typically useful for deciding if an inserted SD card is empty, or
+     * if it contains content like photos that should be preserved.
+     *
+     * @hide
+     */
+    public static int classifyExternalStorageDirectory(File dir) {
+        int res = 0;
+        for (File f : FileUtils.listFilesOrEmpty(dir)) {
+            if (f.isFile() && isInterestingFile(f)) {
+                res |= HAS_OTHER;
+            } else if (f.isDirectory() && hasInterestingFiles(f)) {
+                final String name = f.getName();
+                if (DIRECTORY_MUSIC.equals(name)) res |= HAS_MUSIC;
+                else if (DIRECTORY_PODCASTS.equals(name)) res |= HAS_PODCASTS;
+                else if (DIRECTORY_RINGTONES.equals(name)) res |= HAS_RINGTONES;
+                else if (DIRECTORY_ALARMS.equals(name)) res |= HAS_ALARMS;
+                else if (DIRECTORY_NOTIFICATIONS.equals(name)) res |= HAS_NOTIFICATIONS;
+                else if (DIRECTORY_PICTURES.equals(name)) res |= HAS_PICTURES;
+                else if (DIRECTORY_MOVIES.equals(name)) res |= HAS_MOVIES;
+                else if (DIRECTORY_DOWNLOADS.equals(name)) res |= HAS_DOWNLOADS;
+                else if (DIRECTORY_DCIM.equals(name)) res |= HAS_DCIM;
+                else if (DIRECTORY_DOCUMENTS.equals(name)) res |= HAS_DOCUMENTS;
+                else if (DIRECTORY_ANDROID.equals(name)) res |= HAS_ANDROID;
+                else res |= HAS_OTHER;
+            }
+        }
+        return res;
+    }
+
+    private static boolean hasInterestingFiles(File dir) {
+        final LinkedList<File> explore = new LinkedList<>();
+        explore.add(dir);
+        while (!explore.isEmpty()) {
+            dir = explore.pop();
+            for (File f : FileUtils.listFilesOrEmpty(dir)) {
+                if (isInterestingFile(f)) return true;
+                if (f.isDirectory()) explore.add(f);
+            }
+        }
+        return false;
+    }
+
+    private static boolean isInterestingFile(File file) {
+        if (file.isFile()) {
+            final String name = file.getName().toLowerCase();
+            if (name.endsWith(".exe") || name.equals("autorun.inf")
+                    || name.equals("launchpad.zip") || name.equals(".nomedia")) {
+                return false;
+            } else {
+                return true;
+            }
+        } else {
+            return false;
+        }
+    }
+
     /**
      * Get a top-level shared/external storage directory for placing files of a
      * particular type. This is where the user will typically place and manage