Add xdg mime support on Linux.

base/mime_util_linux.cc

Index: base/mime_util_linux.cc
===================================================================
--- base/mime_util_linux.cc	(revision 0)
+++ base/mime_util_linux.cc	(revision 0)
@@ -0,0 +1,564 @@
+// Copyright (c) 2009 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 "base/mime_util.h"
+
+#include <sys/time.h>
+#include <time.h>
+
+#include <cstdlib>
+#include <list>
+#include <map>
+#include <vector>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/scoped_ptr.h"
+#include "base/singleton.h"
+#include "base/string_util.h"
+#include "base/third_party/xdg_mime/xdgmime.h"
+
+namespace {
+
+class IconTheme;
+
+class MimeUtilConstants {
+ public:
+
+  // In seconds, specified by icon theme specs.
+  const int kUpdateInterval;
+
+  // Store icon directories and their mtimes.
+  std::map<FilePath, int>* icon_dirs;
+
+  // Store icon formats.
+  std::vector<std::string>* icon_formats;
+
+  // Store loaded icon_theme.
+  std::map<std::string, IconTheme*>* icon_themes;
+
+  static const size_t kDefaultThemeNum = 5;
+
+  // The default theme.
+  IconTheme* default_themes[kDefaultThemeNum];
+
+  time_t last_check_time;
+
+ private:
+  MimeUtilConstants()
+      : kUpdateInterval(5),
+        icon_dirs(NULL),
+        icon_formats(NULL),
+        icon_themes(NULL),
+        last_check_time(0) {
+  }
+  friend struct DefaultSingletonTraits<MimeUtilConstants>;
+  DISALLOW_COPY_AND_ASSIGN(MimeUtilConstants);
+};
+
+// IconTheme represents an icon theme as defined by the xdg icon theme spec.
+// Example themes on GNOME include 'Human' and 'Mist'.
+// Example themes on KDE include 'crystalsvg' and 'kdeclassic'.
+class IconTheme {
+ public:
+  // A theme consists of multiple sub-directories, like '32x32' and 'scalable'.
+  class SubDirInfo {
+   public:
+    // See spec for details.
+    enum Type {
+      Fixed,
+      Scalable,
+      Threshold
+    };
+    SubDirInfo()
+        : size(0),
+          type(Threshold),
+          max_size(0),
+          min_size(0),
+          threshold(2) {
+    }
+    size_t size;  // Nominal size of the icons in this directory.
+    Type type;  // Type of the icon size.
+    size_t max_size;  // Maximum size that the icons can be scaled to.
+    size_t min_size;  // Minimum size that the icons can be scaled to.
+    size_t threshold;  // Maximum difference from desired size. 2 by default.
+  };
+
+  explicit IconTheme(const std::string& name);
+
+  ~IconTheme() {
+    delete[] info_array_;
+  }
+
+  // Returns the path to an icon with the name |icon_name| and a size of |size|
+  // pixels. If the icon does not exist, but |inherits| is true, then look for
+  // the icon in the parent theme.
+  FilePath GetIconPath(const std::string& icon_name, int size, bool inherits);
+
+  // Load a theme with the name |theme_name| into memory. Returns null if theme
+  // is invalid.
+  static IconTheme* LoadTheme(const std::string& theme_name);
+
+ private:
+  // Returns the path to an icon with the name |icon_name| in |subdir|.
+  FilePath GetIconPathUnderSubdir(const std::string& icon_name,
+                                  const std::string& subdir);
+
+  // Whether the theme loaded properly.
+  bool IsValid() {
+    return index_theme_loaded_;
+  }
+
+  // Read and parse |file| which is usually named 'index.theme' per theme spec.
+  bool LoadIndexTheme(const FilePath& file);
+
+  // Checks to see if the icons in |info| matches |size| (in pixels). Returns
+  // 0 if they match, or the size difference in pixels.
+  size_t MatchesSize(SubDirInfo* info, size_t size);
+
+  // Yet another function to read a line.
+  std::string ReadLine(FILE* fp);
+
+  // Set directories to search for icons to the comma-separated list |dirs|.
+  bool SetDirectories(const std::string& dirs);
+
+  bool index_theme_loaded_;  // True if an instance is properly loaded.
+  // store the scattered directories of this theme.
+  std::list<FilePath> dirs_;
+
+  // store the subdirs of this theme and array index of |info_array_|.
+  std::map<std::string, int> subdirs_;
+  SubDirInfo* info_array_;  // List of sub-directories.
+  std::string inherits_;  // Name of the theme this one inherits from.
+};
+
+IconTheme::IconTheme(const std::string& name)
+  : index_theme_loaded_(false),
+    info_array_(NULL) {
+  // Iterate on all icon directories to find directories of the specified
+  // theme and load the first encountered index.theme.
+  std::map<FilePath, int>::iterator iter;
+  FilePath theme_path;
+  std::map<FilePath, int>* icon_dirs =
+      Singleton<MimeUtilConstants>::get()->icon_dirs;
+  for (iter = icon_dirs->begin(); iter != icon_dirs->end(); ++iter) {
+    theme_path = iter->first.Append(name);
+    if (!file_util::DirectoryExists(theme_path))
+      continue;
+    FilePath theme_index = theme_path.Append("index.theme");
+    if (!index_theme_loaded_ && file_util::PathExists(theme_index)) {
+      if (!LoadIndexTheme(theme_index))
+        return;
+      index_theme_loaded_ = true;
+    }
+    dirs_.push_back(theme_path);
+  }
+}
+
+FilePath IconTheme::GetIconPath(const std::string& icon_name, int size,
+                                bool inherits) {
+  std::map<std::string, int>::iterator subdir_iter;
+  FilePath icon_path;
+
+  for (subdir_iter = subdirs_.begin();
+       subdir_iter != subdirs_.end();
+       ++subdir_iter) {
+    SubDirInfo* info = &info_array_[subdir_iter->second];
+    if (MatchesSize(info, size) == 0) {
+      icon_path = GetIconPathUnderSubdir(icon_name, subdir_iter->first);
+      if (!icon_path.empty())
+        return icon_path;
+    }
+  }
+  // Now looking for the mostly matched.
+  int min_delta_seen = 9999;
+
+  for (subdir_iter = subdirs_.begin();
+       subdir_iter != subdirs_.end();
+       ++subdir_iter) {
+    SubDirInfo* info = &info_array_[subdir_iter->second];
+    int delta = abs(MatchesSize(info, size));
+    if (delta < min_delta_seen) {
+      FilePath path = GetIconPathUnderSubdir(icon_name, subdir_iter->first);
+      if (!path.empty()) {
+        min_delta_seen = delta;
+        icon_path = path;
+      }
+    }
+  }
+
+  if (!icon_path.empty() || !inherits || inherits_ == "")
+    return icon_path;
+
+  IconTheme* theme = LoadTheme(inherits_);
+  if (theme)
+    return theme->GetIconPath(icon_name, size, inherits);
+  else
+    return FilePath();
+}
+
+IconTheme* IconTheme::LoadTheme(const std::string& theme_name) {
+  scoped_ptr<IconTheme> theme;
+  std::map<std::string, IconTheme*>* icon_themes =
+      Singleton<MimeUtilConstants>::get()->icon_themes;
+  if (icon_themes->find(theme_name) != icon_themes->end()) {
+    theme.reset((*icon_themes)[theme_name]);
+  } else {
+    theme.reset(new IconTheme(theme_name));
+    if (!theme->IsValid())
+      theme.reset();
+    (*icon_themes)[theme_name] = theme.get();
+  }
+  return theme.release();
+}
+
+FilePath IconTheme::GetIconPathUnderSubdir(const std::string& icon_name,
+                                           const std::string& subdir) {
+  FilePath icon_path;
+  std::list<FilePath>::iterator dir_iter;
+  std::vector<std::string>* icon_formats =
+      Singleton<MimeUtilConstants>::get()->icon_formats;
+  for (dir_iter = dirs_.begin(); dir_iter != dirs_.end(); ++dir_iter) {
+    for (size_t i = 0; i < icon_formats->size(); ++i) {
+      icon_path = dir_iter->Append(subdir);
+      icon_path = icon_path.Append(icon_name + (*icon_formats)[i]);
+      if (file_util::PathExists(icon_path))
+        return icon_path;
+    }
+  }
+  return FilePath();
+}
+
+bool IconTheme::LoadIndexTheme(const FilePath& file) {
+  FILE* fp = file_util::OpenFile(file, "r");
+  SubDirInfo* current_info = NULL;
+  if (!fp)
+    return false;
+
+  // Read entries.
+  while (!feof(fp) && !ferror(fp)) {
+    std::string buf = ReadLine(fp);
+    if (buf == "")
+      break;
+
+    std::string entry;
+    TrimWhitespaceASCII(buf, TRIM_ALL, &entry);
+    if (entry.length() == 0 || entry[0] == '#') {
+      // Blank line or Comment.
+      continue;
+    } else if (entry[0] == '[' && info_array_) {
+      current_info = NULL;
+      std::string subdir = entry.substr(1, entry.length() - 2);
+      if (subdirs_.find(subdir) != subdirs_.end())
+        current_info = &info_array_[subdirs_[subdir]];
+    }
+
+    std::string key, value;
+    std::vector<std::string> r;
+    SplitStringDontTrim(entry, '=', &r);
+    if (r.size() < 2)
+      continue;
+
+    TrimWhitespaceASCII(r[0], TRIM_ALL, &key);
+    for (size_t i = 1; i < r.size(); i++)
+      value.append(r[i]);
+    TrimWhitespaceASCII(value, TRIM_ALL, &value);
+
+    if (current_info) {
+      if (key == "Size") {
+        current_info->size = atoi(value.c_str());
+      } else if (key == "Type") {
+        if (value == "Fixed")
+          current_info->type = SubDirInfo::Fixed;
+        else if (value == "Scalable")
+          current_info->type = SubDirInfo::Scalable;
+        else if (value == "Threshold")
+          current_info->type = SubDirInfo::Threshold;
+      } else if (key == "MaxSize") {
+        current_info->max_size = atoi(value.c_str());
+      } else if (key == "MinSize") {
+        current_info->min_size = atoi(value.c_str());
+      } else if (key == "Threshold") {
+        current_info->threshold = atoi(value.c_str());
+      }
+    } else {
+      if (key.compare("Directories") == 0 && !info_array_) {
+        if (!SetDirectories(value)) break;
+      } else if (key.compare("Inherits") == 0) {
+        if (value != "hicolor")
+          inherits_ = value;
+      }
+    }
+  }
+
+  file_util::CloseFile(fp);
+  return info_array_ != NULL;
+}
+
+size_t IconTheme::MatchesSize(SubDirInfo* info, size_t size) {
+  if (info->type == SubDirInfo::Fixed) {
+    return size - info->size;
+  } else if (info->type == SubDirInfo::Scalable) {
+    if (size >= info->min_size && size <= info->max_size) {
+      return 0;
+    } else {
+      return abs(size - info->min_size) < abs(size - info->max_size) ?
+          (size - info->min_size) : (size - info->max_size);
+    }
+  } else {
+    if (size >= info->size - info->threshold &&
+        size <= info->size + info->threshold) {
+      return 0;
+    } else {
+      return abs(size - info->size - info->threshold) <
+          abs(size - info->size + info->threshold)
+          ? size - info->size - info->threshold
+          : size - info->size + info->threshold;
+    }
+  }
+}
+
+std::string IconTheme::ReadLine(FILE* fp) {
+  if (!fp)
+    return "";
+
+  std::string result = "";
+  const size_t kBufferSize = 100;
+  char buffer[kBufferSize];
+  while ((fgets(buffer, kBufferSize - 1, fp)) != NULL) {
+    result += buffer;
+    size_t len = result.length();
+    if (len == 0)
+      break;
+    char end = result[len - 1];
+    if (end == '\n' || end == '\0')
+      break;
+  }
+
+  return result;
+}
+
+bool IconTheme::SetDirectories(const std::string& dirs) {
+  int num = 0;
+  std::string::size_type pos = 0, epos;
+  std::string dir;
+  while ((epos = dirs.find(',', pos)) != std::string::npos) {
+    TrimWhitespaceASCII(dirs.substr(pos, epos - pos), TRIM_ALL, &dir);
+    if (dir.length() == 0) {
+      LOG(WARNING) << "Invalid index.theme: blank subdir";
+      return false;
+    }
+    subdirs_[dir] = num++;
+    pos = epos + 1;
+  }
+  TrimWhitespaceASCII(dirs.substr(pos), TRIM_ALL, &dir);
+  if (dir.length() == 0) {
+    LOG(WARNING) << "Invalid index.theme: blank subdir";
+    return false;
+  }
+  subdirs_[dir] = num++;
+  info_array_ = new SubDirInfo[num];
+  return true;
+}
+
+// Make sure |dir| exists and add it to the list of icon directories.
+void TryAddIconDir(const FilePath& dir) {
+  if (!file_util::DirectoryExists(dir))
+    return;
+  (*Singleton<MimeUtilConstants>::get()->icon_dirs)[dir] = 0;
+}
+
+// For a xdg directory |dir|, add the appropriate icon sub-directories.
+void AddXDGDataDir(const FilePath& dir) {
+  if (!file_util::DirectoryExists(dir))
+    return;
+  TryAddIconDir(dir.Append("icons"));
+  TryAddIconDir(dir.Append("pixmaps"));
+}
+
+// Enable or disable SVG support.
+void EnableSvgIcon(bool enable) {
+  std::vector<std::string>* icon_formats =
+      Singleton<MimeUtilConstants>::get()->icon_formats;
+  icon_formats->clear();
+  icon_formats->push_back(".png");
+  if (enable) {
+    icon_formats->push_back(".svg");
+    icon_formats->push_back(".svgz");
+  }
+  icon_formats->push_back(".xpm");
+}
+
+// Add all the xdg icon directories.
+void InitIconDir() {
+  Singleton<MimeUtilConstants>::get()->icon_dirs->clear();
+  std::string xdg_data_dirs;
+  char* env = getenv("XDG_DATA_HOME");
+  if (!env) {
+    env = getenv("HOME");
+    if (env) {
+      FilePath local_data_dir(env);
+      local_data_dir = local_data_dir.AppendASCII(".local");
+      local_data_dir = local_data_dir.AppendASCII("share");
+      AddXDGDataDir(local_data_dir);
+    }
+  } else {
+    AddXDGDataDir(FilePath(env));
+  }
+
+  env = getenv("XDG_DATA_DIRS");
+  if (!env) {
+    AddXDGDataDir(FilePath("/usr/local/share"));
+    AddXDGDataDir(FilePath("/usr/share"));
+  } else {
+    std::string xdg_data_dirs = env;
+    std::string::size_type pos = 0, epos;
+    while ((epos = xdg_data_dirs.find(':', pos)) != std::string::npos) {
+      AddXDGDataDir(FilePath(xdg_data_dirs.substr(pos, epos - pos)));
+      pos = epos + 1;
+    }
+    AddXDGDataDir(FilePath(xdg_data_dirs.substr(pos)));
+  }
+}
+
+// Per xdg theme spec, we should check the icon directories every so often for
+// newly added icons. This isn't quite right.
+void EnsureUpdated() {
+  struct timeval t;
+  gettimeofday(&t, NULL);
+  time_t now = t.tv_sec;
+  MimeUtilConstants* constants = Singleton<MimeUtilConstants>::get();
+  time_t last_check_time = constants->last_check_time;
+
+  if (last_check_time == 0) {
+    constants->icon_dirs = new std::map<FilePath, int>;
+    constants->icon_themes = new std::map<std::string, IconTheme*>;
+    constants->icon_formats = new std::vector<std::string>;
+    EnableSvgIcon(true);
+    InitIconDir();
+    last_check_time = now;
+  } else {
+    // TODO(thestig): something changed. start over. Upstream fix to Google
+    // Gadgets for Linux.
+    if (now > last_check_time + constants->kUpdateInterval) {
+    }
+  }
+}
+
+// Find a fallback icon if we cannot find it in the default theme.
+FilePath LookupFallbackIcon(const std::string& icon_name) {
+  FilePath icon;
+  MimeUtilConstants* constants = Singleton<MimeUtilConstants>::get();
+  std::map<FilePath, int>::iterator iter;
+  std::map<FilePath, int>* icon_dirs = constants->icon_dirs;
+  std::vector<std::string>* icon_formats = constants->icon_formats;
+  for (iter = icon_dirs->begin(); iter != icon_dirs->end(); ++iter) {
+    for (size_t i = 0; i < icon_formats->size(); ++i) {
+      icon = iter->first.Append(icon_name + (*icon_formats)[i]);
+      if (file_util::PathExists(icon))
+        return icon;
+    }
+  }
+  return FilePath();
+}
+
+// Initialize the list of default themes.
+void InitDefaultThemes() {
+  IconTheme** default_themes =
+      Singleton<MimeUtilConstants>::get()->default_themes;
+  // TODO(thestig): There is no standard way to know about the current icon
+  // theme. So just make a guess. We may be able to do this better. If so,
+  // upstream fix to Google Gadgets for Linux.
+  char* env = getenv("GGL_ICON_THEME");
+  if (env)
+    default_themes[0] = IconTheme::LoadTheme(env);
+
+  env = getenv("KDE_FULL_SESSION");
+  if (env) {
+    env = getenv("KDE_SESSION_VERSION");
+    if (!env || env[0] != '4') {
+      default_themes[1] = IconTheme::LoadTheme("crystalsvg");   // KDE3
+      default_themes[2] = IconTheme::LoadTheme("oxygen");       // KDE4
+    } else {
+      default_themes[1] = IconTheme::LoadTheme("oxygen");       // KDE4
+      default_themes[2] = IconTheme::LoadTheme("crystalsvg");   // KDE3
+    }
+    default_themes[3] = IconTheme::LoadTheme("gnome");
+  } else {  // Assume it's Gnome.
+    default_themes[1] = IconTheme::LoadTheme("gnome");
+    default_themes[2] = IconTheme::LoadTheme("crystalsvg");   // KDE3
+    default_themes[3] = IconTheme::LoadTheme("oxygen");       // KDE4
+  }
+  default_themes[4] = IconTheme::LoadTheme("hicolor");
+}
+
+// Try to find an icon with the name |icon_name| that's |size| pixels.
+FilePath LookupIconInDefaultTheme(const std::string& icon_name, int size) {
+  EnsureUpdated();
+  MimeUtilConstants* constants = Singleton<MimeUtilConstants>::get();
+  std::map<std::string, IconTheme*>* icon_themes = constants->icon_themes;
+  if (icon_themes->size() == 0) InitDefaultThemes();
+
+  FilePath icon_path;
+  IconTheme** default_themes = constants->default_themes;
+  for (size_t i = 0; i < constants->kDefaultThemeNum; i++) {
+    if (default_themes[i]) {
+      icon_path = default_themes[i]->GetIconPath(icon_name, size, true);
+      if (!icon_path.empty())
+        return icon_path;
+    }
+  }
+  return LookupFallbackIcon(icon_name);
+}
+
+}  // namespace
+
+namespace mime_util {
+
+std::string GetFileMimeType(const std::string& file_path) {
+  return xdg_mime_get_mime_type_from_file_name(file_path.c_str());
+}
+
+FilePath GetMimeIcon(const std::string& mime_type, size_t size) {
+  std::vector<std::string> icon_names;
+  std::string icon_name;
+  FilePath icon_file;
+
+  const char* icon = xdg_mime_get_icon(mime_type.c_str());
+  icon_name = std::string(icon ? icon : "");
+  if (icon_name.length())
+    icon_names.push_back(icon_name);
+
+  // For text/plain, try text-plain.
+  icon_name = mime_type;
+  for (size_t i = icon_name.find('/', 0); i != std::string::npos;
+       i = icon_name.find('/', i + 1)) {
+    icon_name[i] = '-';
+  }
+  icon_names.push_back(icon_name);
+  // Also try gnome-mime-text-plain.
+  icon_names.push_back("gnome-mime-" + icon_name);
+
+  // Try generic name like text-x-generic.
+  icon_name = mime_type.substr(0, mime_type.find('/')) + "-x-generic";
+  icon_names.push_back(icon_name);
+
+  // Last resort
+  icon_names.push_back("unknown");
+
+  for (size_t i = 0; i < icon_names.size(); i++) {
+    if (icon_names[i][0] == '/') {
+      icon_file = FilePath(icon_names[i]);
+      if (file_util::PathExists(icon_file))
+        return icon_file;
+    } else {
+      icon_file = LookupIconInDefaultTheme(icon_names[i], size);
+      if (!icon_file.empty())
+        return icon_file;
+    }
+  }
+  return FilePath();
+}
+
+}  // namespace mime_util