1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "filter/ConfigFilter.h"
18
19#include "androidfw/ResourceTypes.h"
20
21#include "ConfigDescription.h"
22
23namespace aapt {
24
25void AxisConfigFilter::AddConfig(ConfigDescription config) {
26  uint32_t diff_mask = ConfigDescription::DefaultConfig().diff(config);
27
28  // Ignore the version
29  diff_mask &= ~android::ResTable_config::CONFIG_VERSION;
30
31  // Ignore any densities. Those are best handled in --preferred-density
32  if ((diff_mask & android::ResTable_config::CONFIG_DENSITY) != 0) {
33    config.density = 0;
34    diff_mask &= ~android::ResTable_config::CONFIG_DENSITY;
35  }
36
37  configs_.insert(std::make_pair(config, diff_mask));
38  config_mask_ |= diff_mask;
39}
40
41// Returns true if the locale script of the config should be considered matching
42// the locale script of entry.
43//
44// If both the scripts are empty, the scripts are considered matching for
45// backward compatibility reasons.
46//
47// If only one script is empty, we try to compute it based on the provided
48// language and country. If we could not compute it, we assume it's either a
49// new language we don't know about, or a private use language. We return true
50// since we don't know any better and they might as well be a match.
51//
52// Finally, when we have two scripts (one of which could be computed), we return
53// true if and only if they are an exact match.
54static bool ScriptsMatch(const ConfigDescription& config, const ConfigDescription& entry) {
55  const char* config_script = config.localeScript;
56  const char* entry_script = entry.localeScript;
57  if (config_script[0] == '\0' && entry_script[0] == '\0') {
58    return true;  // both scripts are empty. We match for backward compatibility reasons.
59  }
60
61  char script_buffer[sizeof(config.localeScript)];
62  if (config_script[0] == '\0') {
63    android::localeDataComputeScript(script_buffer, config.language, config.country);
64    if (script_buffer[0] == '\0') {  // We can't compute the script, so we match.
65      return true;
66    }
67    config_script = script_buffer;
68  } else if (entry_script[0] == '\0') {
69    android::localeDataComputeScript(script_buffer, entry.language, entry.country);
70    if (script_buffer[0] == '\0') {  // We can't compute the script, so we match.
71      return true;
72    }
73    entry_script = script_buffer;
74  }
75  return memcmp(config_script, entry_script, sizeof(config.localeScript)) == 0;
76}
77
78bool AxisConfigFilter::Match(const ConfigDescription& config) const {
79  const uint32_t mask = ConfigDescription::DefaultConfig().diff(config);
80  if ((config_mask_ & mask) == 0) {
81    // The two configurations don't have any common axis.
82    return true;
83  }
84
85  uint32_t matched_axis = 0;
86  for (const auto& entry : configs_) {
87    const ConfigDescription& target = entry.first;
88    const uint32_t diff_mask = entry.second;
89    uint32_t diff = target.diff(config);
90    if ((diff & diff_mask) == 0) {
91      // Mark the axis that was matched.
92      matched_axis |= diff_mask;
93    } else if ((diff & diff_mask) == android::ResTable_config::CONFIG_LOCALE) {
94      // If the locales differ, but the languages are the same and
95      // the locale we are matching only has a language specified,
96      // we match.
97      //
98      // Exception: we won't match if a script is specified for at least
99      // one of the locales and it's different from the other locale's
100      // script. (We will compute the other script if at least one of the
101      // scripts were explicitly set. In cases we can't compute an script,
102      // we match.)
103      if (config.language[0] != '\0' && config.country[0] == '\0' &&
104          config.localeVariant[0] == '\0' && config.language[0] == entry.first.language[0] &&
105          config.language[1] == entry.first.language[1] && ScriptsMatch(config, entry.first)) {
106        matched_axis |= android::ResTable_config::CONFIG_LOCALE;
107      }
108    } else if ((diff & diff_mask) ==
109               android::ResTable_config::CONFIG_SMALLEST_SCREEN_SIZE) {
110      // Special case if the smallest screen width doesn't match. We check that
111      // the
112      // config being matched has a smaller screen width than the filter
113      // specified.
114      if (config.smallestScreenWidthDp != 0 &&
115          config.smallestScreenWidthDp < target.smallestScreenWidthDp) {
116        matched_axis |= android::ResTable_config::CONFIG_SMALLEST_SCREEN_SIZE;
117      }
118    }
119  }
120  return matched_axis == (config_mask_ & mask);
121}
122
123}  // namespace aapt
124