Library loading fallback.

base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java

Index: base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
diff --git a/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java b/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
index 2f922e045b49a910bd1dcbe62b15d7633b66c567..dfb2fd51653078f2537b0ace1ba02b3f9372b76f 100644
--- a/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
+++ b/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
@@ -12,6 +12,8 @@ import org.chromium.base.CommandLine;
 import org.chromium.base.JNINamespace;
 import org.chromium.base.TraceEvent;
 
+import javax.annotation.Nullable;
+
 /**
  * This class provides functionality to load and register the native libraries.
  * Callers are allowed to separate loading the libraries from initializing them.
@@ -53,8 +55,12 @@ public class LibraryLoader {
     private static boolean sIsUsingBrowserSharedRelros = false;
     private static boolean sLoadAtFixedAddressFailed = false;
 
-    // One-way switch becomes true if the library was loaded from the APK file
-    // directly.
+    // One-way switch becomes true if the device supports loading the Chromium
+    // library directly from the APK.
+    private static boolean sLibraryLoadFromApkSupported = false;
+
+    // One-way switch becomes true if the Chromium library was loaded from the
+    // APK file directly.
     private static boolean sLibraryWasLoadedFromApk = false;
 
     // One-way switch becomes false if the Chromium library should be loaded
@@ -168,6 +174,17 @@ public class LibraryLoader {
                 boolean useChromiumLinker = Linker.isUsed();
 
                 if (useChromiumLinker) {
+                    String apkFilename = null;
+
+                    // Check if the device supports loading a library directly from the APK file.
+                    if (context != null) {
+                        apkFilename = context.getApplicationInfo().sourceDir;
+                        sLibraryLoadFromApkSupported = Linker.checkLibraryLoadFromApkSupport(
+                                apkFilename);
+                    } else {
+                        Log.w(TAG, "loadAlreadyLocked(): null context");
+                    }
+
                     // Load libraries using the Chromium linker.
                     Linker.prepareLibraryLoad();
 
@@ -180,26 +197,38 @@ public class LibraryLoader {
                             continue;
                         }
 
-                        String zipfile = null;
-                        if (Linker.isInZipFile()) {
-                            zipfile = context.getApplicationInfo().sourceDir;
-                            sLibraryWasAlignedInApk = Linker.checkLibraryAlignedInApk(
-                                    zipfile, System.mapLibraryName(library));
-                            Log.i(TAG, "Loading " + library + " from within " + zipfile);
+                        // Determine where the library should be loaded from.
+                        String zipFilename = null;

[rmcilroy, 2014/10/29 17:20:43]

zipFilePath and libFilePath

[petrcermak, 2014/10/30 19:55:06]

Done (changed apkFilename to apkFilePath as well).

+                        String libFilename = System.mapLibraryName(library);
+                        if (apkFilename != null && Linker.isInZipFile()) {

[rmcilroy, 2014/10/29 17:20:43]

Do we want to add sLibraryLoadFromApkSupported here?

[petrcermak, 2014/10/30 19:55:06]

Probably not because Anton's fallback for devices with the SELinux permission
problem is in crazy_linker_elf_loader.cpp
(https://codereview.chromium.org/692593002/).

[rmcilroy, 2014/10/31 14:20:21]

Acknowledged.

+                            // The library is in the APK file.
+                            if (!Linker.checkLibraryAlignedInApk(apkFilename, libFilename)) {

[Anton, 2014/10/29 14:18:26]

I think that we should really be checking both alignment and that it is
uncompressed. Currently only alignment is checked. 

This means changes in stuff which has already landed. So probably best to do as
a separate change.

[petrcermak, 2014/10/30 19:55:06]

Agreed (will do in a separate patch).

+                                sLibraryWasAlignedInApk = false;
+                            }
+                            if (sLibraryLoadFromApkSupported && sLibraryWasAlignedInApk) {
+                                // Load directly from the APK.
+                                Log.i(TAG, "Loading " + library + " directly from within " +
+                                        apkFilename);
+                                zipFilename = apkFilename;
+                            } else {
+                                // Fallback.
+                                Log.i(TAG, "Loading " + library + " using fallback from within " +
+                                        apkFilename);
+                                libFilename = LibraryLoaderHelper.buildFallbackLibrary(
+                                        context, apkFilename, libFilename);
+                                Log.i(TAG, "Built fallback library " + libFilename);
+                            }
                         } else {
-                            Log.i(TAG, "Loading: " + library);
+                            // The library is in its own file.
+                            Log.i(TAG, "Loading " + library);
                         }
 
+                        // Load the library.
                         boolean isLoaded = false;
                         if (Linker.isUsingBrowserSharedRelros()) {
                             sIsUsingBrowserSharedRelros = true;
                             try {
-                                if (zipfile != null) {
-                                    Linker.loadLibraryInZipFile(zipfile, library);
-                                    sLibraryWasLoadedFromApk = true;
-                                } else {
-                                    Linker.loadLibrary(library);
-                                }
+                                loadLibrary(zipFilename, libFilename);
                                 isLoaded = true;
                             } catch (UnsatisfiedLinkError e) {
                                 Log.w(TAG, "Failed to load native library with shared RELRO, " +
@@ -209,12 +238,7 @@ public class LibraryLoader {
                             }
                         }
                         if (!isLoaded) {
-                            if (zipfile != null) {
-                                Linker.loadLibraryInZipFile(zipfile, library);
-                                sLibraryWasLoadedFromApk = true;
-                            } else {
-                                Linker.loadLibrary(library);
-                            }
+                            loadLibrary(zipFilename, libFilename);
                         }
                     }
 
@@ -265,6 +289,15 @@ public class LibraryLoader {
         }
     }
 
+    // Load a native shared library with the Chromium linker. If the zip file
+    // filename is not null, the library is loaded directly from the zip file.
+    private static void loadLibrary(@Nullable String zipFilename, String libFilename) {

[rmcilroy, 2014/10/29 17:20:43]

zipFilePath and libFilePath

[petrcermak, 2014/10/30 19:55:06]

Done.

+        if (zipFilename != null) {
+            sLibraryWasLoadedFromApk = true;
+        }
+        Linker.loadLibrary(zipFilename, libFilename);
+    }
+
     // The WebView requires the Command Line to be switched over before
     // initialization is done. This is okay in the WebView's case since the
     // JNI is already loaded by this point.