Merge bitcoin/bitcoin#25057: refactor: replace remaining boost::split with SplitString

f849e63bad963b8717d4bc45efdad9b08567a36e fuzz: SplitString with multiple separators (Martin Leitner-Ankerl)
d1a9850102fe572b8a1e00b80c757dd82bf39f9d http: replace boost::split with SplitString (Martin Leitner-Ankerl)
0d7efcdf75607e19fac77bcd146773a03af14492 core_read: Replace boost::split with SplitString (Martin Leitner-Ankerl)
b7ab9db545492927b774912e53aeb834a590621f Extend Split to work with multiple separators (Martin Leitner-Ankerl)

Pull request description:

  As a followup of #22953, this removes the remaining occurrences of `boost::split` and replaces them with our own `SplitString`. To be able to do so, this extends the function `spanparsing::Split` to work with multiple separators. Finally this removes 3 more files from `lint-includes.py`.

ACKs for top commit:
  theStack:
    Code-review ACK f849e63bad963b8717d4bc45efdad9b08567a36e

Tree-SHA512: f37d4dbe11cab2046e646045b0f018a75f978d521443a2c5001512737a1370e22b09247d5db0e5c9e4153229a4e2d66731903c1bba3713711c4cae8cedcc775d

7 files changed, 49 insertions, 18 deletions

diff --git a/src/core_read.cpp b/src/core_read.cpp
index 3bab5b5d98..77c516427a 100644
--- a/src/core_read.cpp
+++ b/src/core_read.cpp
@@ -14,9 +14,6 @@
 #include <util/strencodings.h>
 #include <version.h>
 
-#include <boost/algorithm/string/classification.hpp>
-#include <boost/algorithm/string/split.hpp>
-
 #include <algorithm>
 #include <string>
 
@@ -66,12 +63,11 @@ CScript ParseScript(const std::string& s)
 {
     CScript result;
 
-    std::vector<std::string> words;
-    boost::algorithm::split(words, s, boost::algorithm::is_any_of(" \t\n"), boost::algorithm::token_compress_on);
+    std::vector<std::string> words = SplitString(s, " \t\n");
 
     for (const std::string& w : words) {
         if (w.empty()) {
-            // Empty string, ignore. (boost::split given '' will return one word)
+            // Empty string, ignore. (SplitString doesn't combine multiple separators)
         } else if (std::all_of(w.begin(), w.end(), ::IsDigit) ||
                    (w.front() == '-' && w.size() > 1 && std::all_of(w.begin() + 1, w.end(), ::IsDigit)))
         {
diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index af27ff3506..3bf165495c 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -21,8 +21,6 @@
 #include <string>
 #include <vector>
 
-#include <boost/algorithm/string.hpp>
-
 /** WWW-Authenticate to present with 401 Unauthorized response */
 static const char* WWW_AUTH_HEADER_DATA = "Basic realm=\"jsonrpc\"";
 
@@ -276,8 +274,10 @@ static bool InitRPCAuthentication()
         std::set<std::string>& whitelist = g_rpc_whitelist[strUser];
         if (pos != std::string::npos) {
             std::string strWhitelist = strRPCWhitelist.substr(pos + 1);
-            std::set<std::string> new_whitelist;
-            boost::split(new_whitelist, strWhitelist, boost::is_any_of(", "));
+            std::vector<std::string> whitelist_split = SplitString(strWhitelist, ", ");
+            std::set<std::string> new_whitelist{
+                std::make_move_iterator(whitelist_split.begin()),
+                std::make_move_iterator(whitelist_split.end())};
             if (intersect) {
                 std::set<std::string> tmp_whitelist;
                 std::set_intersection(new_whitelist.begin(), new_whitelist.end(),
diff --git a/src/test/fuzz/string.cpp b/src/test/fuzz/string.cpp
index e6064d19b6..94399faf04 100644
--- a/src/test/fuzz/string.cpp
+++ b/src/test/fuzz/string.cpp
@@ -224,7 +224,12 @@ FUZZ_TARGET(string)
         int64_t amount_out;
         (void)ParseFixedPoint(random_string_1, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 1024), &amount_out);
     }
-    (void)SplitString(random_string_1, fuzzed_data_provider.ConsumeIntegral<char>());
+    {
+        const auto single_split{SplitString(random_string_1, fuzzed_data_provider.ConsumeIntegral<char>())};
+        assert(single_split.size() >= 1);
+        const auto any_split{SplitString(random_string_1, random_string_2)};
+        assert(any_split.size() >= 1);
+    }
     {
         (void)Untranslated(random_string_1);
         const bilingual_str bs1{random_string_1, random_string_2};
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index b880a7a9fd..890b2f997e 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -2396,6 +2396,19 @@ BOOST_AUTO_TEST_CASE(test_SplitString)
         BOOST_CHECK_EQUAL(result.size(), 1);
         BOOST_CHECK_EQUAL(result[0], "AAA");
     }
+
+    // multiple split characters
+    {
+        using V = std::vector<std::string>;
+        BOOST_TEST(SplitString("a,b.c:d;e", ",;") == V({"a", "b.c:d", "e"}));
+        BOOST_TEST(SplitString("a,b.c:d;e", ",;:.") == V({"a", "b", "c", "d", "e"}));
+        BOOST_TEST(SplitString("a,b.c:d;e", "") == V({"a,b.c:d;e"}));
+        BOOST_TEST(SplitString("aaa", "bcdefg") == V({"aaa"}));
+        BOOST_TEST(SplitString("x\0a,b"s, "\0"s) == V({"x", "a,b"}));
+        BOOST_TEST(SplitString("x\0a,b"s, '\0') == V({"x", "a,b"}));
+        BOOST_TEST(SplitString("x\0a,b"s, "\0,"s) == V({"x", "a", "b"}));
+        BOOST_TEST(SplitString("abcdefg", "bcd") == V({"a", "", "", "efg"}));
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_LogEscapeMessage)
diff --git a/src/util/spanparsing.h b/src/util/spanparsing.h
index ebec8714a7..51795271de 100644
--- a/src/util/spanparsing.h
+++ b/src/util/spanparsing.h
@@ -8,6 +8,7 @@
 #include <span.h>
 
 #include <string>
+#include <string_view>
 #include <vector>
 
 namespace spanparsing {
@@ -36,7 +37,7 @@ bool Func(const std::string& str, Span<const char>& sp);
  */
 Span<const char> Expr(Span<const char>& sp);
 
-/** Split a string on every instance of sep, returning a vector.
+/** Split a string on any char found in separators, returning a vector.
  *
  * If sep does not occur in sp, a singleton with the entirety of sp is returned.
  *
@@ -44,13 +45,13 @@ Span<const char> Expr(Span<const char>& sp);
  * "foo(bar(1),2),3) on ',' will return {"foo(bar(1)", "2)", "3)"}.
  */
 template <typename T = Span<const char>>
-std::vector<T> Split(const Span<const char>& sp, char sep)
+std::vector<T> Split(const Span<const char>& sp, std::string_view separators)
 {
     std::vector<T> ret;
     auto it = sp.begin();
     auto start = it;
     while (it != sp.end()) {
-        if (*it == sep) {
+        if (separators.find(*it) != std::string::npos) {
             ret.emplace_back(start, it);
             start = it + 1;
         }
@@ -60,6 +61,19 @@ std::vector<T> Split(const Span<const char>& sp, char sep)
     return ret;
 }
 
+/** Split a string on every instance of sep, returning a vector.
+ *
+ * If sep does not occur in sp, a singleton with the entirety of sp is returned.
+ *
+ * Note that this function does not care about braces, so splitting
+ * "foo(bar(1),2),3) on ',' will return {"foo(bar(1)", "2)", "3)"}.
+ */
+template <typename T = Span<const char>>
+std::vector<T> Split(const Span<const char>& sp, char sep)
+{
+    return Split<T>(sp, std::string_view{&sep, 1});
+}
+
 } // namespace spanparsing
 
 #endif // BITCOIN_UTIL_SPANPARSING_H
diff --git a/src/util/string.h b/src/util/string.h
index 36b9787db4..2e91347b27 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -14,6 +14,7 @@
 #include <locale>
 #include <sstream>
 #include <string>
+#include <string_view>
 #include <vector>
 
 [[nodiscard]] inline std::vector<std::string> SplitString(std::string_view str, char sep)
@@ -21,6 +22,11 @@
     return spanparsing::Split<std::string>(str, sep);
 }
 
+[[nodiscard]] inline std::vector<std::string> SplitString(std::string_view str, std::string_view separators)
+{
+    return spanparsing::Split<std::string>(str, separators);
+}
+
 [[nodiscard]] inline std::string_view TrimStringView(std::string_view str, std::string_view pattern = " \f\n\r\t\v")
 {
     std::string::size_type front = str.find_first_not_of(pattern);
diff --git a/test/lint/lint-includes.py b/test/lint/lint-includes.py
index b29c7f8b4d..ae62994642 100755
--- a/test/lint/lint-includes.py
+++ b/test/lint/lint-includes.py
@@ -21,10 +21,7 @@ EXCLUDED_DIRS = ["src/leveldb/",
                  "src/minisketch/",
                  "src/univalue/"]
 
-EXPECTED_BOOST_INCLUDES = ["boost/algorithm/string.hpp",
-                           "boost/algorithm/string/classification.hpp",
-                           "boost/algorithm/string/replace.hpp",
-                           "boost/algorithm/string/split.hpp",
+EXPECTED_BOOST_INCLUDES = ["boost/algorithm/string/replace.hpp",
                            "boost/date_time/posix_time/posix_time.hpp",
                            "boost/multi_index/hashed_index.hpp",
                            "boost/multi_index/ordered_index.hpp",