From 908e0dfda568ddf0eb7f12e555655818241acda8 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Mon, 18 Nov 2019 16:01:21 -0800
Subject: [PATCH] Add absl-like StringReplace.

Needed for cli-test.

Test: treehugger
Change-Id: Ib1fd01ef7f3e54e5778cc548dd789b5fcfcb7bd9
---
 base/include/android-base/strings.h |  5 ++++
 base/strings.cpp                    | 19 +++++++++++++
 base/strings_test.cpp               | 43 +++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/base/include/android-base/strings.h b/base/include/android-base/strings.h
index b1c22c9f7..14d534a3b 100644
--- a/base/include/android-base/strings.h
+++ b/base/include/android-base/strings.h
@@ -85,5 +85,10 @@ inline bool ConsumeSuffix(std::string_view* s, std::string_view suffix) {
   return true;
 }
 
+// Replaces `from` with `to` in `s`, once if `all == false`, or as many times as
+// there are matches if `all == true`.
+[[nodiscard]] std::string StringReplace(std::string_view s, std::string_view from,
+                                        std::string_view to, bool all);
+
 }  // namespace base
 }  // namespace android
diff --git a/base/strings.cpp b/base/strings.cpp
index bb3167ef0..40b2bf270 100644
--- a/base/strings.cpp
+++ b/base/strings.cpp
@@ -116,5 +116,24 @@ bool EqualsIgnoreCase(std::string_view lhs, std::string_view rhs) {
   return lhs.size() == rhs.size() && strncasecmp(lhs.data(), rhs.data(), lhs.size()) == 0;
 }
 
+std::string StringReplace(std::string_view s, std::string_view from, std::string_view to,
+                          bool all) {
+  if (from.empty()) return std::string(s);
+
+  std::string result;
+  std::string_view::size_type start_pos = 0;
+  do {
+    std::string_view::size_type pos = s.find(from, start_pos);
+    if (pos == std::string_view::npos) break;
+
+    result.append(s.data() + start_pos, pos - start_pos);
+    result.append(to.data(), to.size());
+
+    start_pos = pos + from.size();
+  } while (all);
+  result.append(s.data() + start_pos, s.size() - start_pos);
+  return result;
+}
+
 }  // namespace base
 }  // namespace android
diff --git a/base/strings_test.cpp b/base/strings_test.cpp
index ca3c0b83e..5ae309446 100644
--- a/base/strings_test.cpp
+++ b/base/strings_test.cpp
@@ -311,3 +311,46 @@ TEST(strings, ConsumeSuffix) {
   ASSERT_TRUE(android::base::ConsumeSuffix(&s, ".bar"));
   ASSERT_EQ("foo", s);
 }
+
+TEST(strings, StringReplace_false) {
+  // No change.
+  ASSERT_EQ("abcabc", android::base::StringReplace("abcabc", "z", "Z", false));
+  ASSERT_EQ("", android::base::StringReplace("", "z", "Z", false));
+  ASSERT_EQ("abcabc", android::base::StringReplace("abcabc", "", "Z", false));
+
+  // Equal lengths.
+  ASSERT_EQ("Abcabc", android::base::StringReplace("abcabc", "a", "A", false));
+  ASSERT_EQ("aBcabc", android::base::StringReplace("abcabc", "b", "B", false));
+  ASSERT_EQ("abCabc", android::base::StringReplace("abcabc", "c", "C", false));
+
+  // Longer replacement.
+  ASSERT_EQ("foobcabc", android::base::StringReplace("abcabc", "a", "foo", false));
+  ASSERT_EQ("afoocabc", android::base::StringReplace("abcabc", "b", "foo", false));
+  ASSERT_EQ("abfooabc", android::base::StringReplace("abcabc", "c", "foo", false));
+
+  // Shorter replacement.
+  ASSERT_EQ("xxyz", android::base::StringReplace("abcxyz", "abc", "x", false));
+  ASSERT_EQ("axyz", android::base::StringReplace("abcxyz", "bcx", "x", false));
+  ASSERT_EQ("abcx", android::base::StringReplace("abcxyz", "xyz", "x", false));
+}
+
+TEST(strings, StringReplace_true) {
+  // No change.
+  ASSERT_EQ("abcabc", android::base::StringReplace("abcabc", "z", "Z", true));
+  ASSERT_EQ("", android::base::StringReplace("", "z", "Z", true));
+  ASSERT_EQ("abcabc", android::base::StringReplace("abcabc", "", "Z", true));
+
+  // Equal lengths.
+  ASSERT_EQ("AbcAbc", android::base::StringReplace("abcabc", "a", "A", true));
+  ASSERT_EQ("aBcaBc", android::base::StringReplace("abcabc", "b", "B", true));
+  ASSERT_EQ("abCabC", android::base::StringReplace("abcabc", "c", "C", true));
+
+  // Longer replacement.
+  ASSERT_EQ("foobcfoobc", android::base::StringReplace("abcabc", "a", "foo", true));
+  ASSERT_EQ("afoocafooc", android::base::StringReplace("abcabc", "b", "foo", true));
+  ASSERT_EQ("abfooabfoo", android::base::StringReplace("abcabc", "c", "foo", true));
+
+  // Shorter replacement.
+  ASSERT_EQ("xxyzx", android::base::StringReplace("abcxyzabc", "abc", "x", true));
+  ASSERT_EQ("<xx>", android::base::StringReplace("<abcabc>", "abc", "x", true));
+}