Improve support for external keyboards.

Use Vendor ID, Product ID and optionally the Version to
locate keymaps and configuration files for external devices.

Moved virtual key definition parsing to native code so that
EventHub can identify touch screens with virtual keys and load
the appropriate key layout file.

Cleaned up a lot of old code in EventHub.

Fixed a regression in ViewRoot's fallback event handling.

Fixed a minor bug in FileMap that caused it to try to munmap
or close invalid handled when released if the attempt to map
the file failed.

Added a couple of new String8 conveniences for formatting strings.

Modified Tokenizer to fall back to open+read when mmap fails since
we can't mmap sysfs files as needed to open the virtual key
definition files in /sys/board_properties/.

Change-Id: I6ca5e5f9547619fd082ddac47e87ce185da69ee6
diff --git a/libs/utils/Tokenizer.cpp b/libs/utils/Tokenizer.cpp
index 9251973..b3445b7 100644
--- a/libs/utils/Tokenizer.cpp
+++ b/libs/utils/Tokenizer.cpp
@@ -35,16 +35,16 @@
     return strchr(delimiters, ch) != NULL;
 }
 
-
-Tokenizer::Tokenizer(const String8& filename, FileMap* fileMap,
-        const char* buffer, size_t length) :
-        mFilename(filename), mFileMap(fileMap), mBuffer(buffer), mLength(length),
-        mCurrent(buffer), mLineNumber(1) {
+Tokenizer::Tokenizer(const String8& filename, FileMap* fileMap, char* buffer, size_t length) :
+        mFilename(filename), mFileMap(fileMap),
+        mBuffer(buffer), mLength(length), mCurrent(buffer), mLineNumber(1) {
 }
 
 Tokenizer::~Tokenizer() {
     if (mFileMap) {
         mFileMap->release();
+    } else {
+        delete[] mBuffer;
     }
 }
 
@@ -63,22 +63,33 @@
             LOGE("Error getting size of file '%s', %s.", filename.string(), strerror(errno));
         } else {
             size_t length = size_t(stat.st_size);
-            FileMap* fileMap = new FileMap();
-            if (!fileMap->create(NULL, fd, 0, length, true)) {
-                result = NO_MEMORY;
-                LOGE("Error mapping file '%s', %s.", filename.string(), strerror(errno));
-            } else {
-                fileMap->advise(FileMap::SEQUENTIAL);
 
-                *outTokenizer = new Tokenizer(filename, fileMap,
-                        static_cast<const char*>(fileMap->getDataPtr()), length);
-                if (!*outTokenizer) {
-                    result = NO_MEMORY;
-                    LOGE("Error allocating tokenizer for file=%s.", filename.string());
+            FileMap* fileMap = new FileMap();
+            char* buffer;
+            if (fileMap->create(NULL, fd, 0, length, true)) {
+                fileMap->advise(FileMap::SEQUENTIAL);
+                buffer = static_cast<char*>(fileMap->getDataPtr());
+            } else {
+                fileMap->release();
+                fileMap = NULL;
+
+                // Fall back to reading into a buffer since we can't mmap files in sysfs.
+                // The length we obtained from stat is wrong too (it will always be 4096)
+                // so we must trust that read will read the entire file.
+                buffer = new char[length];
+                ssize_t nrd = read(fd, buffer, length);
+                if (nrd < 0) {
+                    result = -errno;
+                    LOGE("Error reading file '%s', %s.", filename.string(), strerror(errno));
+                    delete[] buffer;
+                    buffer = NULL;
+                } else {
+                    length = size_t(nrd);
                 }
             }
-            if (result) {
-                fileMap->release();
+
+            if (!result) {
+                *outTokenizer = new Tokenizer(filename, fileMap, buffer, length);
             }
         }
         close(fd);