ozone: evdev: Add gesture property provider

ui/events/ozone/evdev/libgestures_glue/gesture_property_provider.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/events/ozone/evdev/libgestures_glue/gesture_property_provider.h"
+
+#include <gestures/gestures.h>
+#include <libevdev/libevdev.h>
+
+#include <fnmatch.h>
+#include <string.h>
+
+#include <algorithm>
+#include <iostream>
+#include <set>
+
+#include "base/files/file_enumerator.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringize_macros.h"
+#include "base/strings/stringprintf.h"
+
+// Severity level for general info logging purpose.
+#define INFO_SEVERITY INFO

[spang, 2014/09/18 21:23:16]

Please don't rename this. You shouldn't use LOG(INFO), there's a presubmit that
will complain if you do it.

Use:

VLOG(n) if you want to support logging even in release builds
DVLOG(n) if you want to support logging only in debug

LOG(WARNING) and LOG(ERROR) are also OK for real problems.

[Shecky Lin, 2014/09/19 09:31:08]

Done.

+
+/* Implementation of GesturesProp declared in gestures.h
+ *
+ * libgestures requires that this be in the top level namespace.
+ * */
+struct GesturesProp {
+  GesturesProp()
+      : type(ui::GesturePropertyProvider::PT_INT),
+        count(1),
+        is_allocated(false),
+        is_managed_externally(true),
+        write_back(NULL),
+        handler_data(NULL),
+        get(NULL),
+        set(NULL) {
+    val.v = NULL;
+  }
+  // Free the data pointer. Should never be called if the GesturesProp is
+  // created from the gesture lib side.
+  void Free() {
+    if (count > 1)
+      (*data_pointer_deallocator_map_[type])(val);
+    else
+      (*data_array_pointer_deallocator_map_[type])(val);
+  }
+
+  // For logging purpose.
+  friend std::ostream& operator<<(std::ostream& os, const GesturesProp& prop);
+
+  // Property name, type and number of elements.
+  std::string name;
+  ui::GesturePropertyProvider::PropertyType type;
+  size_t count;
+
+  // Data pointer.
+  union Data {
+    void* v;
+    int* i;
+    short* h;
+    GesturesPropBool* b;
+    std::string* s;
+    double* r;
+  } val;
+
+  // If the flag is on, it means the memory that the data pointer points to is
+  // allocated here. We will need to free the memory by ourselves when the
+  // GesturesProp is destroyed (GesturesPropFunctionsWrapper::Free is called).
+  bool is_allocated;
+
+  // If the flag is off, it means the GesturesProp is created by passing a NULL
+  // data pointer to the creator functions. We will need to free the memory by
+  // ourselves when the GesturePropertyProvider is destroyed because no other
+  // people will be able to do it. For GesturesProp created with non-NULL
+  // pointers, external users are responsible of handling its data memory (via
+  // the GesturesPropProvider APIs).
+  //
+  // Note that the flag is different from is_allocated because the string
+  // properties are always allocated here whether it is created with NULL or
+  // not. In short, if this flag is false, then is_allocated must be true.
+  bool is_managed_externally;
+
+  // In some cases, we don't directly use the data pointer provided by the
+  // creators due to its limitation and instead use our own types (e.g., in
+  // the case of string). We thus need to store the write back pointer so that
+  // we can update the value in the gesture lib if the property value gets
+  // changed.
+  void* write_back;
+
+  // Handler function pointers and the data to be passed to them when the
+  // property is accessed.
+  void* handler_data;
+  GesturesPropGetHandler get;
+  GesturesPropSetHandler set;
+ private:
+  // Trick for appropriately deallocating the data memory based on its type.
+  typedef std::map<ui::GesturePropertyProvider::PropertyType,
+                   void (*)(GesturesProp::Data&)> DeallocatorMap;
+  template <typename T>
+  static void DataPointerDeallocator(Data& data) {
+    delete reinterpret_cast<T>(data.v);
+  }
+  template <typename T>
+  static void DataArrayPointerDeallocator(Data& data) {
+    delete[] reinterpret_cast<T>(data.v);
+  }
+  template <typename T>
+  static void InsertDeallocator(DeallocatorMap* deallocator_map,
+                                ui::GesturePropertyProvider::PropertyType type,
+                                const bool is_array) {
+    if (is_array) {
+      deallocator_map->insert(
+          std::make_pair(type, &DataArrayPointerDeallocator<T*>));
+    } else {
+      deallocator_map->insert(
+          std::make_pair(type, &DataPointerDeallocator<T*>));
+    }
+  }
+
+  // Populate deallocators in the deallocator map.
+  static DeallocatorMap CreateDataPointerDeallocatorMap(const bool is_array) {
+    DeallocatorMap result;
+    // Macro for adding GesturesProp data pointer deallocators.
+#define REGISTER_GPROP_DEALLOCATOR(NAME, TYPE) \
+  InsertDeallocator<TYPE>(&result, ui::GesturePropertyProvider::NAME, is_array)
+    REGISTER_GPROP_DEALLOCATOR(PT_INT, int);
+    REGISTER_GPROP_DEALLOCATOR(PT_SHORT, short);
+    REGISTER_GPROP_DEALLOCATOR(PT_BOOL, GesturesPropBool);
+    REGISTER_GPROP_DEALLOCATOR(PT_STRING, std::string);
+    REGISTER_GPROP_DEALLOCATOR(PT_REAL, double);
+#undef REGISTER_GPROP_DEALLOCATOR
+    return result;
+  }
+
+  // These deallocator maps store deallocators for different data types.
+  static DeallocatorMap data_pointer_deallocator_map_;

[spang, 2014/09/18 21:23:16]

static objects with nontrivial initialization aren't allowed. There's actually a
perf bot that will catch this and go red.

It looks like this could be done with a switch/case - no static object needed.

Then again, I think what you really want is a virtual destructor. Then you can
just do "delete my_prop" inside Free().

[Shecky Lin, 2014/09/19 09:31:08]

Done. Thanks for the great suggestion.

+  static DeallocatorMap data_array_pointer_deallocator_map_;
+};
+
+// Trick for initializing static map members.
+GesturesProp::DeallocatorMap GesturesProp::data_pointer_deallocator_map_(
+    GesturesProp::CreateDataPointerDeallocatorMap(false));
+GesturesProp::DeallocatorMap GesturesProp::data_array_pointer_deallocator_map_(
+    GesturesProp::CreateDataPointerDeallocatorMap(true));
+
+// Property type logging function.
+std::ostream& operator<<(std::ostream& out,
+                         const ui::GesturePropertyProvider::PropertyType type) {
+  std::string s;
+#define TYPE_CASE(TYPE)                     \
+  case (ui::GesturePropertyProvider::TYPE): \
+    s = #TYPE;                              \
+    break;
+  switch (type) {
+    TYPE_CASE(PT_INT);
+    TYPE_CASE(PT_SHORT);
+    TYPE_CASE(PT_BOOL);
+    TYPE_CASE(PT_STRING);
+    TYPE_CASE(PT_REAL);
+    default:
+      s = "Unknown type";
+      break;
+  }
+#undef TYPE_CASE
+  return out << s;
+}
+
+// GesturesProp logging function.
+std::ostream& operator<<(std::ostream& os, const GesturesProp& prop) {
+  os << "\"" << prop.name << "\", " << prop.type << ", " << prop.count << ", ("
+     << prop.is_allocated << ", " << prop.is_managed_externally << "), "
+     << prop.write_back << ", (";
+  bool known_prop_type = true;
+  for (size_t i = 0; (i < prop.count) && known_prop_type; i++) {
+    switch (prop.type) {
+      case ui::GesturePropertyProvider::PT_INT:
+        os << prop.val.i[i];
+        break;
+      case ui::GesturePropertyProvider::PT_SHORT:
+        os << prop.val.h[i];
+        break;
+      case ui::GesturePropertyProvider::PT_BOOL:
+        // Prevent the value being printed as characters.
+        os << static_cast<int>(prop.val.b[i]);
+        break;
+      case ui::GesturePropertyProvider::PT_STRING:
+        os << prop.val.s[i];
+        break;
+      case ui::GesturePropertyProvider::PT_REAL:
+        os << prop.val.r[i];
+        break;
+      default:
+        LOG(ERROR) << "Unknown gesture property type: " << prop.type;
+        known_prop_type = false;
+        break;
+    }
+    os << ", ";
+  }
+  os << ")";
+  return os;
+}
+
+namespace ui {
+
+// The path that we will look for conf files.
+const char kConfigurationFilePath[] = "/etc/gesture";
+
+// We support only match types that have already been used. One should change
+// this if we start using new types in the future. Note that most unsupported
+// match types are either useless in CrOS or inapplicable to the non-X
+// environment.
+const char* kSupportedMatchTypes[] = {"MatchProduct",
+                                      "MatchDevicePath",
+                                      "MatchUSBID",
+                                      "MatchIsPointer",
+                                      "MatchIsTouchpad",
+                                      "MatchIsTouchscreen"};
+const char* kUnsupportedMatchTypes[] = {"MatchVendor",
+                                        "MatchOS",
+                                        "MatchPnPID",
+                                        "MatchDriver",
+                                        "MatchTag",
+                                        "MatchLayout",
+                                        "MatchIsKeyboard",
+                                        "MatchIsJoystick",
+                                        "MatchIsTablet"};
+
+// Special keywords for boolean values.
+const char* kTrue[] = {"on", "true", "yes"};
+const char* kFalse[] = {"off", "false", "no"};
+
+// Trick to get the device path from a file descriptor.
+std::string GetDeviceNodePath(void* dev) {
+  std::string proc_symlink =
+      "/proc/self/fd/" + base::IntToString(static_cast<Evdev*>(dev)->fd);
+  base::FilePath path;
+  if (!base::ReadSymbolicLink(base::FilePath(proc_symlink), &path))
+    return std::string();
+  return path.value();
+}
+
+GesturePropertyProvider* GesturePropertyProvider::GetInstance() {
+  return Singleton<GesturePropertyProvider>::get();
+}
+
+GesturePropertyProvider::GesturePropertyProvider() : device_id_counter_(0) {
+  RegisterMatchCriterias();
+  LoadDeviceConfigurations();
+}
+
+GesturePropertyProvider::~GesturePropertyProvider() {
+  // Note that we don't need to free most GesturesProp data pointers - they are
+  // managed externally through the GesturesPropProvider APIs. However, some
+  // props are created by directly calling the APIs with NULL pointers so they
+  // still need to be handled here.
+  DevicePropertyMap::iterator it = properties_maps_.begin();
+  for (; it != properties_maps_.end(); ++it) {
+    PropertyMap::iterator ip = it->second->begin();
+    for (; ip != it->second->end(); ++ip)
+      if (!ip->second->is_managed_externally)
+        ip->second->Free();
+  }
+
+  // We do need to free the data pointers for props in configurations_ as they
+  // are maintained by ourselves. The props in default_properties_maps_ are all
+  // referenced from configurations_ so they are OK.
+  for (size_t i = 0; i < configurations_.size(); i++) {
+    for (size_t j = 0; j < configurations_[i].criterias.size(); j++)
+      delete configurations_[i].criterias[j];

[alexst (slow to review), 2014/09/18 16:13:29]

Thank you for the scoped_ptr_hash map change. Can you more the rest of the
manually created/destroyed memory to use scoped_ptr or scoped_ref_ptr? Manual
memory management is harder to trace and tends to be more fragile.

[Shecky Lin, 2014/09/19 09:31:08]

Yeah, I am still looking into this. Will do it at the next patch.

+    for (size_t j = 0; j < configurations_[i].properties.size(); j++)
+      configurations_[i].properties[j].Free();
+  }
+}
+
+void GesturePropertyProvider::RegisterMatchCriterias() {
+  // Macro for registering match criteria derived classes.
+#define REGISTER_MATCH_CRITERIA(NAME) \
+  match_criteria_map_[#NAME] =        \
+      &ui::GesturePropertyProvider::AllocateMatchCriteria<NAME>
+  REGISTER_MATCH_CRITERIA(MatchProduct);
+  REGISTER_MATCH_CRITERIA(MatchDevicePath);
+  REGISTER_MATCH_CRITERIA(MatchUSBID);
+  REGISTER_MATCH_CRITERIA(MatchIsPointer);
+  REGISTER_MATCH_CRITERIA(MatchIsTouchpad);
+  REGISTER_MATCH_CRITERIA(MatchIsTouchscreen);
+#undef REGISTER_MATCH_CRITERIA
+  // TODO(sheckylin): Add a check here to make sure all match criterias in
+  // kSupportedMatchTypes is registered here. Otherwise, let the derived
+  // classess register themselves instead.
+}
+
+void GesturePropertyProvider::GetDeviceIndices(
+    const DeviceType type,
+    std::vector<DeviceId>* device_ids) {
+  device_ids->clear();
+  DeviceIdMap::iterator it = device_ids_map_.begin();
+  for (; it != device_ids_map_.end(); ++it) {
+    // Check if the device matches the type.
+    it->first;
+    device_ids->push_back(it->second);
+  }
+}
+
+GesturePropertyProvider::DeviceId GesturePropertyProvider::GetDeviceId(
+    DevicePtr dev,
+    const bool do_create) {
+  DeviceIdMap::iterator it = device_ids_map_.find(dev);
+  if (it != device_ids_map_.end())
+    return it->second;
+  if (!do_create)
+    return -1;
+
+  // Insert a new one if not exists.
+  // TODO(sheckylin): Replace this id generation scheme with a better one.
+  // The current way may result in memory leaks.
+  DeviceId id = device_id_counter_;
+  device_ids_map_[dev] = id;
+  properties_maps_.set(id, scoped_ptr<PropertyMap>(new PropertyMap));
+  device_id_counter_ = (device_id_counter_ + 1) % kMaxDeviceNum;
+
+  // Apply default prop values for the device.
+  SetupDefaultProperties(id, dev);
+  return id;
+}
+
+void GesturePropertyProvider::GetProperty(const DeviceId device_id,
+                                          const std::string& name,
+                                          DeviceType* type,
+                                          PropertyValuePtr* val,
+                                          size_t* count) {
+  // Implement PropertyGet in cmt.
+  NOTIMPLEMENTED();
+}
+
+void GesturePropertyProvider::SetProperty(const DeviceId device_id,
+                                          const std::string& name,
+                                          const DeviceType type,
+                                          const PropertyValuePtr val,
+                                          const size_t count) {
+  // Implement PropertySet in cmt.
+  NOTIMPLEMENTED();
+}
+
+GesturePropertyProvider::MatchCriteria::MatchCriteria(const std::string& arg) {
+  // TODO(sheckylin): Should we trim all tokens here?
+  Tokenize(arg, "|", &args_);
+}
+
+GesturePropertyProvider::MatchProduct::MatchProduct(const std::string& arg)
+    : MatchCriteria(arg) {
+}
+
+bool GesturePropertyProvider::MatchProduct::Match(DevicePtr device) {
+  if (args_.empty())
+    return true;
+  std::string name(device->info.name);
+  for (size_t i = 0; i < args_.size(); i++)
+    if (name.find(args_[i]) != std::string::npos)
+      return true;
+  return false;
+}
+
+GesturePropertyProvider::MatchDevicePath::MatchDevicePath(
+    const std::string& arg)
+    : MatchCriteria(arg) {
+}
+
+bool GesturePropertyProvider::MatchDevicePath::Match(DevicePtr device) {
+  if (args_.empty())
+    return true;
+
+  // Check if the device path matches any pattern.
+  std::string path = GetDeviceNodePath(device);
+  if (path.empty())
+    return false;
+  for (size_t i = 0; i < args_.size(); i++)
+    if (fnmatch(args_[i].c_str(), path.c_str(), FNM_NOESCAPE) == 0)
+      return true;
+  return false;
+}
+
+GesturePropertyProvider::MatchUSBID::MatchUSBID(const std::string& arg)
+    : MatchCriteria(arg) {
+  // Check each pattern and split valid ones into vids and pids.
+  for (size_t i = 0; i < args_.size(); i++) {
+    if (!IsValidPattern(args_[i]))
+      continue;
+    std::vector<std::string> tokens;
+    base::SplitString(args_[i], ':', &tokens);
+    vid_patterns_.push_back(base::StringToLowerASCII(tokens[0]));
+    pid_patterns_.push_back(base::StringToLowerASCII(tokens[1]));
+  }
+}
+
+bool GesturePropertyProvider::MatchUSBID::Match(DevicePtr device) {
+  if (vid_patterns_.empty())
+    return true;
+  std::string vid = base::StringPrintf("%04x", device->info.id.vendor);
+  std::string pid = base::StringPrintf("%04x", device->info.id.product);
+  for (size_t i = 0; i < vid_patterns_.size(); i++) {
+    if (fnmatch(vid_patterns_[i].c_str(), vid.c_str(), FNM_NOESCAPE) == 0 &&
+        fnmatch(pid_patterns_[i].c_str(), pid.c_str(), FNM_NOESCAPE) == 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool GesturePropertyProvider::MatchUSBID::IsValidPattern(
+    const std::string& pattern) {
+  // Each USB id should be in the lsusb format, i.e., xxxx:xxxx. We choose to do
+  // a lazy check here: if the pattern contains wrong characters not in the hex
+  // number range, it won't be matched anyway.
+  int number_of_colons = 0;
+  size_t pos_of_colon = 0;
+  for (size_t i = 0; i < pattern.size(); i++)
+    if (pattern[i] == ':')
+      ++number_of_colons, pos_of_colon = i;
+  return (number_of_colons == 1) && (pos_of_colon != 0) &&
+         (pos_of_colon != pattern.size() - 1);
+}
+
+GesturePropertyProvider::MatchDeviceType::MatchDeviceType(
+    const std::string& arg)
+    : MatchCriteria(arg), value_(true), is_valid_(false) {
+  // Default value of a match criteria is true.
+  if (args_.empty())
+    args_.push_back("on");
+
+  // We care only about the first argument.
+  int value = ParseBooleanKeyword(args_[0]);
+  if (value) {
+    is_valid_ = true;
+    value_ = value > 0;
+  }
+}
+
+GesturePropertyProvider::MatchIsPointer::MatchIsPointer(const std::string& arg)
+    : MatchDeviceType(arg) {
+}
+
+bool GesturePropertyProvider::MatchIsPointer::Match(DevicePtr device) {
+  if (!is_valid_)
+    return true;
+  return (value_ == (device->info.evdev_class == EvdevClassMouse ||
+                     device->info.evdev_class == EvdevClassMultitouchMouse));
+}
+
+GesturePropertyProvider::MatchIsTouchpad::MatchIsTouchpad(
+    const std::string& arg)
+    : MatchDeviceType(arg) {
+}
+
+bool GesturePropertyProvider::MatchIsTouchpad::Match(DevicePtr device) {
+  if (!is_valid_)
+    return true;
+  return (value_ == (device->info.evdev_class == EvdevClassTouchpad));
+}
+
+GesturePropertyProvider::MatchIsTouchscreen::MatchIsTouchscreen(
+    const std::string& arg)
+    : MatchDeviceType(arg) {
+}
+
+bool GesturePropertyProvider::MatchIsTouchscreen::Match(DevicePtr device) {
+  if (!is_valid_)
+    return true;
+  return (value_ == (device->info.evdev_class == EvdevClassTouchscreen));
+}
+
+bool GesturePropertyProvider::ConfigurationSection::Match(DevicePtr device) {
+  for (size_t i = 0; i < criterias.size(); ++i)
+    if (!criterias[i]->Match(device))
+      return false;
+  return true;
+}
+
+void GesturePropertyProvider::AddProperty(const DeviceId device_id,
+                                          const std::string& name,
+                                          GesturesProp* prop) {
+  // The look-up should never fail because ideally a property can only be
+  // created with GesturesPropCreate* functions from the gesture lib side.
+  // Therefore, we simply return on failure.
+  DevicePropertyMap::iterator it = properties_maps_.find(device_id);
+  if (it != properties_maps_.end())
+    it->second->insert(std::make_pair(name, prop));
+}
+
+void GesturePropertyProvider::DeleteProperty(const DeviceId device_id,
+                                             const std::string& name) {
+  DevicePropertyMap::iterator it = properties_maps_.find(device_id);
+  if (it != properties_maps_.end())
+    it->second->erase(name);
+}
+
+GesturesProp* GesturePropertyProvider::FindProperty(const DeviceId device_id,
+                                                    const std::string& name) {
+  return FindProperty(properties_maps_, device_id, name);
+}
+
+GesturesProp* GesturePropertyProvider::FindProperty(
+    const DevicePropertyMap& device_property_map,
+    const DeviceId device_id,
+    const std::string& name) {
+  DevicePropertyMap::const_iterator ia = device_property_map.find(device_id);
+  if (ia == properties_maps_.end())
+    return NULL;
+  PropertyMap::const_iterator ib = ia->second->find(name);
+  if (ib == ia->second->end())
+    return NULL;
+  return ib->second;
+}
+
+GesturesProp* GesturePropertyProvider::GetDefaultProperty(
+    const DeviceId device_id,
+    const std::string& name) {
+  return FindProperty(default_properties_maps_, device_id, name);
+}
+
+void GesturePropertyProvider::LoadDeviceConfigurations() {
+  // Enumerate conf files and sort them lexicographically.
+  std::set<base::FilePath> files;
+  base::FileEnumerator file_enum(base::FilePath(kConfigurationFilePath),
+                                 false,
+                                 base::FileEnumerator::FILES,
+                                 "*.conf");
+  for (base::FilePath path = file_enum.Next(); !path.empty();
+       path = file_enum.Next()) {
+    files.insert(path);
+  }
+  LOG(INFO_SEVERITY) << files.size() << " conf files were found";
+
+  // Parse conf files one-by-one.
+  for (std::set<base::FilePath>::iterator file_iter = files.begin();
+       file_iter != files.end();
+       ++file_iter) {
+    LOG(INFO_SEVERITY) << "Parsing conf file: " << (*file_iter).value();
+    std::string content;
+    if (!base::ReadFileToString(*file_iter, &content)) {
+      LOG(ERROR) << "Can't loading gestures conf file: "
+                 << (*file_iter).value();
+      continue;
+    }
+    ParseXorgConfFile(content);
+  }
+}
+
+void GesturePropertyProvider::ParseXorgConfFile(const std::string& content) {
+  // To simplify the parsing work, we made some assumption about the conf file
+  // format which doesn't exist in the original xorg-conf spec. Most important
+  // ones are:
+  // 1. All keywords and names are now case-sensitive. Also, underscores are not
+  //    ignored.
+  // 2. Each entry takes up one and exactly one line in the file.
+  // 3. No negation of the option value even if the option name is prefixed with
+  //    "No" as it may cause problems for option names that does start with "No"
+  //    (e.g., "Non-linearity").
+
+  // Break the content into sections, lines and then pieces.
+  // Sections are delimited by the "EndSection" keyword.
+  // Lines are delimited by "\n".
+  // Pieces are delimited by all white-spaces.
+  std::vector<std::string> sections;
+  base::SplitStringUsingSubstr(content, "EndSection", &sections);
+  for (size_t i = 0; i < sections.size(); ++i) {
+    // Create a new configuration section.
+    configurations_.push_back(ConfigurationSection());
+    ConfigurationSection& config = configurations_.back();
+
+    // Break the section into lines.
+    base::StringTokenizer lines(sections[i], "\n");
+    bool is_input_class_section = true;
+    bool has_checked_section_type = false;
+    while (is_input_class_section && lines.GetNext()) {
+      // Parse the line w.r.t. the xorg-conf format.
+      std::string line(lines.token());
+
+      // Skip empty lines.
+      if (line.empty())
+        continue;
+
+      // Treat all whitespaces as delimiters.
+      base::StringTokenizer pieces(line, base::kWhitespaceASCII);
+      pieces.set_quote_chars("\"");
+      bool is_parsing = false;
+      bool has_error = false;
+      bool next_is_section_type = false;
+      bool next_is_option_name = false;
+      bool next_is_option_value = false;
+      bool next_is_match_criteria = false;
+      bool next_is_identifier = false;
+      std::string match_type, option_name;
+      while (pieces.GetNext()) {
+        std::string piece(pieces.token());
+
+        // Skip empty pieces.
+        if (piece.empty())
+          continue;
+
+        // See if we are currently parsing an entry or are still looking for
+        // one.
+        if (is_parsing) {
+          // Stop parsing the current line if the format is wrong.
+          if (piece.size() <= 2 || piece[0] != '\"' ||
+              piece[piece.size() - 1] != '\"') {
+            LOG(ERROR) << "Error parsing line: " << lines.token();
+            has_error = true;
+            if (next_is_section_type)
+              is_input_class_section = false;
+            break;
+          }
+
+          // Parse the arguments. Note that we don't break even if a whitespace
+          // string is passed. It will just be handled in various ways based on
+          // the entry type.
+          std::string arg;
+          base::TrimWhitespaceASCII(
+              piece.substr(1, piece.size() - 2), base::TRIM_ALL, &arg);
+          if (next_is_section_type) {
+            // We only care about InputClass sections.
+            if (arg != "InputClass") {
+              has_error = true;
+              is_input_class_section = false;
+            } else {
+              LOG(INFO_SEVERITY) << "New InputClass section found";
+              has_checked_section_type = true;
+            }
+            break;
+          } else if (next_is_identifier) {
+            LOG(INFO_SEVERITY) << "Identifier: " << arg;
+            config.identifier = arg;
+            next_is_identifier = false;
+            break;
+          } else if (next_is_option_name) {
+            // TODO(sheckylin): Support option "Ignore".
+            option_name = arg;
+            next_is_option_value = true;
+            next_is_option_name = false;
+          } else if (next_is_option_value) {
+            GesturesProp prop;
+            if(CreateDefaultProperty(option_name, arg, &prop))
+              config.properties.push_back(prop);
+            next_is_option_value = false;
+            break;
+          } else if (next_is_match_criteria) {
+            // Skip all match types that are not supported.
+            if (IsMatchTypeSupported(match_type)) {
+              MatchCriteria *criteria = CreateMatchCriteria(match_type, arg);
+              if (criteria)
+                config.criterias.push_back(criteria);
+            }
+            next_is_match_criteria = false;
+            break;
+          }
+        } else {
+          // If the section type hasn't been decided yet, look for it.
+          // Otherwise, look for valid entries according to the spec.
+          if (has_checked_section_type) {
+            if (piece == "Driver") {
+              // TODO(sheckylin): Support "Driver" so that we can force a device
+              // not to use the gesture lib.
+              NOTIMPLEMENTED();
+              break;
+            } else if (piece == "Identifier") {
+              is_parsing = true;
+              next_is_identifier = true;
+              continue;
+            } else if (piece == "Option") {
+              is_parsing = true;
+              next_is_option_name = true;
+              continue;
+            } else if (piece.size() > 5 && piece.compare(0, 5, "Match") == 0) {
+              match_type = piece;
+              is_parsing = true;
+              next_is_match_criteria = true;
+              continue;
+            }
+          } else if (piece == "Section") {
+            is_parsing = true;
+            next_is_section_type = true;
+            continue;
+          }
+
+          // If none of the above is found, check if the current piece starts a
+          // comment.
+          if (piece.empty() || piece[0] != '#') {
+            LOG(ERROR) << "Error parsing line: " << lines.token();
+            has_error = true;
+          }
+          break;
+        }
+      }
+
+      // The value of a boolean option is skipped (default is true).
+      if (!has_error && (next_is_option_value || next_is_match_criteria)) {
+        if (next_is_option_value) {
+          GesturesProp prop;
+          if (CreateDefaultProperty(option_name, "on", &prop))
+            config.properties.push_back(prop);
+        } else if (IsMatchTypeSupported(match_type) &&
+                   IsDeviceMatchType(match_type)) {
+          MatchCriteria* criteria = CreateMatchCriteria(match_type, "on");
+          if (criteria)
+            config.criterias.push_back(criteria);
+        }
+      }
+    }
+
+    // Remove useless config sections.
+    if (!is_input_class_section ||
+        (config.criterias.empty() && config.properties.empty())) {
+      configurations_.pop_back();
+    }
+  }
+}
+
+bool GesturePropertyProvider::IsMatchTypeSupported(
+    const std::string& match_type) {
+  for (size_t i = 0; i < arraysize(kSupportedMatchTypes); i++)
+    if (match_type == kSupportedMatchTypes[i])
+      return true;
+  for (size_t i = 0; i < arraysize(kUnsupportedMatchTypes); i++) {
+    if (match_type == kUnsupportedMatchTypes[i]) {
+      LOG(ERROR) << "Unsupported gestures input class match type: "
+                 << match_type;
+      return false;
+    }
+  }
+  return false;
+}
+
+bool GesturePropertyProvider::IsDeviceMatchType(
+    const std::string& match_type) {
+  return StartsWithASCII(match_type, "MatchIs", true);
+}
+
+GesturePropertyProvider::MatchCriteria*
+GesturePropertyProvider::CreateMatchCriteria(const std::string& match_type,
+                                             const std::string& arg) {
+  LOG(INFO_SEVERITY) << "Creating match criteria: (" << match_type << ", "
+                     << arg << ")";
+  return (this->*match_criteria_map_[match_type])(arg);
+}
+
+bool GesturePropertyProvider::CreateDefaultProperty(const std::string& name,
+                                                    const std::string& value,
+                                                    GesturesProp* prop) {
+  // Our parsing rule:
+  // 1. No hex or oct number is accepted.
+  // 2. All numbers will be stored as double.
+  // 3. Array elements can be separated by both white-spaces or commas.
+  // 4. A token is treated as numeric either if it is one of the special
+  //    keywords for boolean values (on, true, yes, off, false, no) or if
+  //    base::StringToDouble succeeds.
+  // 5. The property is treated as numeric if and only if all of its elements
+  //    (if any) are numerics. Otherwise, it will be treated as a string.
+  // 6. A string property will be trimmed before storing its value.
+  LOG(INFO_SEVERITY) << "Creating default property: (" << name << ", " << value
+                     << ")";
+
+  // Parse elements one-by-one.
+  std::string delimiters(base::kWhitespaceASCII);
+  delimiters.append(",");
+  base::StringTokenizer tokens(value, delimiters);
+  bool is_all_numeric = true;
+  std::vector<double> numbers;
+  while (tokens.GetNext()) {
+    // Skip empty tokens.
+    std::string token(tokens.token());
+    if (token.empty())
+      continue;
+
+    // Check if it is a boolean keyword.
+    int bool_result = ParseBooleanKeyword(token);
+    if (bool_result) {
+      numbers.push_back(bool_result > 0);
+      continue;
+    }
+
+    // Check if it is a number.
+    double real_result;
+    bool success = base::StringToDouble(token, &real_result);
+    if (!success) {
+      is_all_numeric = false;
+      break;
+    }
+    numbers.push_back(real_result);
+  }
+
+  // Setup GesturesProp data.
+  prop->name = name;
+  // Arrays need to contain at least one number and may contain numbers only.
+  if (is_all_numeric && numbers.size()) {
+    prop->type = PT_REAL;
+    prop->count = numbers.size();
+    prop->val.r = new double[numbers.size()];
+    std::copy(numbers.begin(), numbers.end(), prop->val.r);
+  } else {
+    prop->type = PT_STRING;
+    prop->count = 1;
+    std::string trimmed;
+    base::TrimWhitespaceASCII(value, base::TRIM_ALL, &trimmed);
+    prop->val.s = new std::string(trimmed);
+  }
+
+  LOG(INFO_SEVERITY) << "Prop: " << *prop;
+  // The function will always succeed for now but it may change later if we
+  // specify some name or args as invalid.
+  return true;
+}
+
+int GesturePropertyProvider::ParseBooleanKeyword(const std::string& value) {
+  for (size_t i = 0; i < arraysize(kTrue); i++)
+    if (LowerCaseEqualsASCII(value, kTrue[i]))
+      return 1;
+  for (size_t i = 0; i < arraysize(kFalse); i++)
+    if (LowerCaseEqualsASCII(value, kFalse[i]))
+      return -1;
+  return 0;
+}
+
+void GesturePropertyProvider::SetupDefaultProperties(
+    const DeviceId device_id,
+    DevicePtr dev) {
+  LOG(INFO_SEVERITY) << "Setting up default properties for (" << dev << ", "
+                     << device_id << ", " << dev->info.name << ")";
+
+  // Go through all parsed sections.
+  scoped_ptr<PropertyMap> prop_map(new PropertyMap);
+  for (size_t i = 0; i < configurations_.size(); i++) {
+    if (configurations_[i].Match(dev)) {
+      LOG(INFO_SEVERITY) << "Conf section \"" << configurations_[i].identifier
+                         << "\" is matched";
+      for (size_t j = 0; j < configurations_[i].properties.size(); j++) {
+        GesturesProp& prop = configurations_[i].properties[j];
+        // We can't use insert here because a property may be set for several
+        // times along the way.
+        (*prop_map)[prop.name] = &prop;
+      }
+    }
+  }
+  default_properties_maps_.set(device_id, prop_map.Pass());
+}
+
+template <typename T>
+GesturesProp* GesturesPropFunctionsWrapper::Create(
+    void* dev,
+    const char* name,
+    GesturePropertyProvider::PropertyType type,
+    T* val,
+    size_t count) {
+  // Create a new PropertyMap for the device if not exists already.
+  GesturePropertyProvider::DeviceId device_id =
+      GesturePropertyProvider::GetInstance()->GetDeviceId(dev, true);
+
+  /* Insert property and setup property values */
+
+  // First, see if the GesturesProp already exists.
+  DVLOG(3) << "Creating Property: \"" << name << "\"";
+  GesturesProp* prop =
+      GesturePropertyProvider::GetInstance()->FindProperty(device_id, name);
+  if (!prop) {
+    prop = new GesturesProp();
+    GesturePropertyProvider::GetInstance()->AddProperty(device_id, name, prop);
+  } else if (prop->is_allocated) {
+    // Free the data pointer if it was allocated here. This shouldn't happen in
+    // normal use cases (that a read only property being declared again).
+    // However, we want to prevent any possible memory leak if it does happen.
+    prop->Free();
+  }
+
+  // Set the values.
+  prop->name = name;
+  prop->type = type;
+  prop->count = count;
+
+  // Allocate memory for the data if a NULL pointer is provided.
+  if (!val) {
+    if (count > 1)
+      prop->val.v = new T[count];
+    else
+      prop->val.v = new T;
+    prop->is_allocated = true;
+  } else {
+    prop->val.v = val;
+  }
+  return prop;
+}
+
+template <typename T, GesturePropertyProvider::PropertyType type>
+GesturesProp* GesturesPropFunctionsWrapper::CreateProperty(void* dev,
+                                                           const char* name,
+                                                           T* val,
+                                                           size_t count,
+                                                           const T* init) {
+  GesturesProp* result = Create(dev, name, type, val, count);
+  if (!val)
+    result->is_managed_externally = false;
+
+  // We currently assumed that we won't specify any array property in the
+  // configuration files. The code needs to be updated if the assumption becomes
+  // invalid in the future.
+  if (count == 1) {
+    GesturesProp* default_prop =
+        GesturePropertyProvider::GetInstance()->GetDefaultProperty(
+            GesturePropertyProvider::GetInstance()->GetDeviceId(dev), name);
+    if (!default_prop ||
+        default_prop->type == GesturePropertyProvider::PT_STRING) {
+      *(reinterpret_cast<T*>(result->val.v)) = *init;
+    } else {
+      LOG(INFO_SEVERITY) << "Default property found. Using its value ...";
+      // TODO(sheckylin): Handle value out-of-range (e.g., double to int).
+      *(reinterpret_cast<T*>(result->val.v)) =
+          static_cast<T>(*(default_prop->val.r));
+    }
+  } else {
+    memmove(result->val.v, init, count * sizeof(T));
+  }
+
+  LOG(INFO_SEVERITY) << "Created active prop: " << *result;
+  return result;
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateInt(void* dev,
+                                                      const char* name,
+                                                      int* val,
+                                                      size_t count,
+                                                      const int* init) {
+  return CreateProperty<int, GesturePropertyProvider::PT_INT>(
+      dev, name, val, count, init);
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateShort(void* dev,
+                                                        const char* name,
+                                                        short* val,
+                                                        size_t count,
+                                                        const short* init) {
+  return CreateProperty<short, GesturePropertyProvider::PT_SHORT>(
+      dev, name, val, count, init);
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateBool(
+    void* dev,
+    const char* name,
+    GesturesPropBool* val,
+    size_t count,
+    const GesturesPropBool* init) {
+  return CreateProperty<GesturesPropBool, GesturePropertyProvider::PT_BOOL>(
+      dev, name, val, count, init);
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateReal(void* dev,
+                                                       const char* name,
+                                                       double* val,
+                                                       size_t count,
+                                                       const double* init) {
+  return CreateProperty<double, GesturePropertyProvider::PT_REAL>(
+      dev, name, val, count, init);
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateString(void* dev,
+                                                         const char* name,
+                                                         const char** val,
+                                                         const char* init) {
+  // StringProperty's memory is always allocated on this side instead of
+  // externally in the gesture lib as the original one will be destroyed right
+  // after the constructor call (check the design of StringProperty). To do
+  // this, we call the Create function with NULL pointer so that it always
+  // allocates.
+  GesturesProp* result = Create(dev,
+                                name,
+                                GesturePropertyProvider::PT_STRING,
+                                static_cast<std::string*>(NULL),
+                                1);
+  if (!val)
+    result->is_managed_externally = false;
+
+  GesturesProp* default_prop =
+      GesturePropertyProvider::GetInstance()->GetDefaultProperty(
+          GesturePropertyProvider::GetInstance()->GetDeviceId(dev), name);
+
+  // Setup its value just like the other data types.
+  if (!default_prop ||
+      default_prop->type != GesturePropertyProvider::PT_STRING) {
+    *(result->val.s) = init;
+  } else {
+    LOG(INFO_SEVERITY) << "Default property found. Using its value ...";
+    *(result->val.s) = *(default_prop->val.s);
+  }
+
+  // If the provided pointer is not NULL, replace its content
+  // (val_ of StringProperty) with the address of our allocated string.
+  // Note that we don't have to do this for the other data types as they will
+  // use the original data pointer if possible and it is unnecessary to do so
+  // if the pointer is NULL.
+  if (val) {
+    *(val) = result->val.s->c_str();
+    result->write_back = val;
+  }
+
+  LOG(INFO_SEVERITY) << "Created active prop: " << *result;
+  return result;
+}
+
+void GesturesPropFunctionsWrapper::RegisterHandlers(
+    void* priv,
+    GesturesProp* prop,
+    void* handler_data,
+    GesturesPropGetHandler get,
+    GesturesPropSetHandler set) {
+  // Sanity checks
+  if (!priv || !prop)
+    return;
+
+  prop->handler_data = handler_data;
+  prop->get = get;
+  prop->set = set;
+}
+
+void GesturesPropFunctionsWrapper::Free(void* priv, GesturesProp* prop) {
+  if (!prop)
+    return;
+
+  GesturePropertyProvider::DeviceId device_id =
+      GesturePropertyProvider::GetInstance()->GetDeviceId(priv);
+  if (device_id < 0)
+    return;
+
+  DVLOG(3) << "Freeing Property: \"" << prop->name << "\"";
+  GesturePropertyProvider::GetInstance()->DeleteProperty(device_id, prop->name);
+  if (prop->is_allocated)
+    prop->Free();
+  delete prop;
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateIntSingle(
+    void* dev,
+    const char* name,
+    int* val,
+    int init) {
+  return CreateInt(dev, name, val, 1, &init);
+}
+
+GesturesProp* GesturesPropFunctionsWrapper::CreateBoolSingle(
+    void* dev,
+    const char* name,
+    GesturesPropBool* val,
+    GesturesPropBool init) {
+  return CreateBool(dev, name, val, 1, &init);
+}
+
+bool GesturesPropFunctionsWrapper::InitializeDeviceProperties(
+    void* device, GesturePropertyProvider::DeviceProperty* props) {
+  if (!device)
+    return false;
+  GesturePropertyProvider::DevicePtr dev =
+      static_cast<GesturePropertyProvider::DevicePtr>(device);
+
+  /* Create Device Properties */
+
+  // Read Only properties.
+  CreateString(dev, "Device Node", NULL, GetDeviceNodePath(dev).c_str());
+  CreateShort(dev,
+              "Device Vendor ID",
+              NULL,
+              1,
+              reinterpret_cast<short*>(&(dev->info.id.vendor)));
+  CreateShort(dev,
+              "Device Product ID",
+              NULL,
+              1,
+              reinterpret_cast<short*>(&(dev->info.id.product)));
+
+  // Useable trackpad area. If not configured in .conf file,
+  // use x/y valuator min/max as reported by kernel driver.
+  CreateIntSingle(
+      dev, "Active Area Left", &props->area_left, Event_Get_Left(dev));
+  CreateIntSingle(
+      dev, "Active Area Right", &props->area_right, Event_Get_Right(dev));
+  CreateIntSingle(dev, "Active Area Top", &props->area_top, Event_Get_Top(dev));
+  CreateIntSingle(
+      dev, "Active Area Bottom", &props->area_bottom, Event_Get_Bottom(dev));
+
+  // Trackpad resolution (pixels/mm). If not configured in .conf file,
+  // use x/y resolution as reported by kernel driver.
+  CreateIntSingle(
+      dev, "Vertical Resolution", &props->res_y, Event_Get_Res_Y(dev));
+  CreateIntSingle(
+      dev, "Horizontal Resolution", &props->res_x, Event_Get_Res_X(dev));
+
+  // Trackpad orientation minimum/maximum. If not configured in .conf file,
+  // use min/max as reported by kernel driver.
+  CreateIntSingle(dev,
+                  "Orientation Minimum",
+                  &props->orientation_minimum,
+                  Event_Get_Orientation_Minimum(dev));
+  CreateIntSingle(dev,
+                  "Orientation Maximum",
+                  &props->orientation_maximum,
+                  Event_Get_Orientation_Maximum(dev));
+
+  // Log dump property. Will call Event_Dump_Debug_Log when its value is being
+  // set.
+  GesturesProp* dump_debug_log_prop =
+      CreateBoolSingle(dev, "Dump Debug Log", &props->dump_debug_log, false);
+  RegisterHandlers(dev, dump_debug_log_prop, dev, NULL, Event_Dump_Debug_Log);
+
+  // Whether to do the gesture recognition or just passing the multi-touch data
+  // to upper layers.
+  CreateBoolSingle(
+      dev, "Raw Touch Passthrough", &props->raw_passthrough, false);
+  return true;
+}
+
+/* Global GesturesPropProvider
+ *
+ * Used by PropRegistry in GestureInterpreter to forward property value
+ * creations from there.
+ * */
+const GesturesPropProvider kGesturePropProvider = {
+    GesturesPropFunctionsWrapper::CreateInt,
+    GesturesPropFunctionsWrapper::CreateShort,
+    GesturesPropFunctionsWrapper::CreateBool,
+    GesturesPropFunctionsWrapper::CreateString,
+    GesturesPropFunctionsWrapper::CreateReal,
+    GesturesPropFunctionsWrapper::RegisterHandlers,
+    GesturesPropFunctionsWrapper::Free};
+
+}  // namespace ui