1 /*
2 * Copyright (C) 2020 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 #include "linkerconfig/stringutil.h"
17
18 #include <type_traits>
19 #include <unordered_set>
20 #include <vector>
21
22 #include <android-base/strings.h>
23
24 namespace android {
25 namespace linkerconfig {
26 namespace modules {
TrimPrefix(const std::string & s,const std::string & prefix)27 std::string TrimPrefix(const std::string& s, const std::string& prefix) {
28 if (android::base::StartsWith(s, prefix)) {
29 return s.substr(prefix.size());
30 }
31 return s;
32 }
33
34 // merge a list of libs into a single value (concat with ":")
MergeLibs(const std::vector<std::string> & libs)35 std::string MergeLibs(const std::vector<std::string>& libs) {
36 std::unordered_set<std::string_view> seen;
37 std::string out;
38 bool first = true;
39 for (const auto& part : libs) {
40 const char* part_str = part.c_str();
41 const char* part_end = part.c_str() + part.size();
42 while (part_str != part_end) {
43 const void* end = memchr(part_str, ':', part_end - part_str);
44 const char* end_str = end ? static_cast<const char*>(end) : part_end;
45 std::string_view lib(part_str, end_str - part_str);
46 static_assert(
47 std::is_const_v<typeof(libs)>,
48 "libs needs to be const so we can use a string_view in seen");
49 if (!lib.empty() && seen.insert(lib).second) { // for a new lib
50 if (!first) {
51 out += ':';
52 }
53 out += lib;
54 first = false;
55 }
56 if (end == nullptr) break;
57 part_str = end_str + 1;
58 }
59 }
60 return out;
61 }
62 } // namespace modules
63 } // namespace linkerconfig
64 } // namespace android