Factorize split_once functions

mamba-org · Nov 3, 2023 · 768b392 · 768b392
1 parent 95f00f2
commit 768b392
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Showing 5 changed files with 138 additions and 15 deletions.
diff --git a/libmamba/include/mamba/util/string.hpp b/libmamba/include/mamba/util/string.hpp
@@ -12,9 +12,11 @@
 #include <cstdint>
 #include <cstring>
 #include <iomanip>
+#include <optional>
 #include <sstream>
 #include <string>
 #include <string_view>
+#include <tuple>
 #include <type_traits>
 #include <utility>
 #include <vector>
@@ -192,6 +194,16 @@ namespace mamba::util
     template <typename UnaryFunc>
     std::array<std::wstring_view, 3> strip_if_parts(std::wstring_view input, UnaryFunc should_strip);
 
+    [[nodiscard]] auto split_once(std::string_view str, char sep)
+        -> std::tuple<std::string_view, std::optional<std::string_view>>;
+    [[nodiscard]] auto split_once(std::string_view str, std::string_view sep)
+        -> std::tuple<std::string_view, std::optional<std::string_view>>;
+
+    [[nodiscard]] auto rsplit_once(std::string_view str, char sep)
+        -> std::tuple<std::optional<std::string_view>, std::string_view>;
+    [[nodiscard]] auto rsplit_once(std::string_view str, std::string_view sep)
+        -> std::tuple<std::optional<std::string_view>, std::string_view>;
+
     std::vector<std::string>
     split(std::string_view input, std::string_view sep, std::size_t max_split = SIZE_MAX);
     std::vector<std::wstring>

diff --git a/libmamba/src/core/channel.cpp b/libmamba/src/core/channel.cpp
@@ -206,16 +206,6 @@ namespace mamba
             }
         }
 
-        auto rsplit_once(std::string_view str, char sep)
-        {
-            auto [head, tail] = util::rstrip_if_parts(str, [sep](char c) { return c != sep; });
-            if (head.empty())
-            {
-                return std::array{ head, tail };
-            }
-            return std::array{ head.substr(0, head.size() - 1), tail };
-        }
-
         auto
         make_platforms(util::flat_set<std::string> filters, const std::vector<std::string>& defaults)
         {
@@ -234,16 +224,16 @@ namespace mamba
     {
         auto uri = specs::CondaURL::parse(util::path_or_url_to_url(spec.location()));
 
-        auto path = uri.pretty_path();
-        auto [parent, current] = rsplit_once(path, '/');
+        auto path = util::rstrip(uri.pretty_path(), '/');
+        auto [parent, current] = util::rsplit_once(path, '/');
         for (const auto& [canonical_name, chan] : get_custom_channels())
         {
             if (url_match(chan.url(), uri))
             {
                 return Channel(
                     /* url= */ std::move(uri),
                     /* location= */ chan.url().pretty_str(specs::CondaURL::StripScheme::yes),
-                    /* name= */ std::string(util::rstrip(parent, '/')),
+                    /* name= */ std::string(util::rstrip(parent.value_or(""), '/')),
                     /* canonical_name= */ std::string(canonical_name)
                 );
             }
@@ -263,7 +253,7 @@ namespace mamba
         auto canonical_name = uri.pretty_str();
         return Channel(
             /* url= */ std::move(uri),
-            /* location= */ std::string(util::rstrip(parent, '/')),
+            /* location= */ std::string(util::rstrip(parent.value_or(""), '/')),
             /* name= */ std::string(util::rstrip(current, '/')),
             /* canonical_name= */ std::move(canonical_name)
         );

diff --git a/libmamba/src/util/string.cpp b/libmamba/src/util/string.cpp
@@ -556,6 +556,65 @@ namespace mamba::util
         return strip_parts_impl(input, chars);
     }
 
+    /********************************************
+     *  Implementation of split_once functions  *
+     ********************************************/
+
+    namespace
+    {
+        template <typename Char, typename CharOrStrView>
+        auto split_once_impl(std::basic_string_view<Char> str, CharOrStrView sep)
+            -> std::tuple<std::string_view, std::optional<std::string_view>>
+        {
+            static constexpr auto npos = std::basic_string_view<Char>::npos;
+            if (const auto pos = str.find(sep); pos != npos)
+            {
+                return { str.substr(0, pos), str.substr(pos + detail::length(sep)) };
+            }
+            return { str, std::nullopt };
+        }
+    }
+
+    auto split_once(std::string_view str, char sep)
+        -> std::tuple<std::string_view, std::optional<std::string_view>>
+    {
+        return split_once_impl(str, sep);
+    }
+
+    auto split_once(std::string_view str, std::string_view sep)
+        -> std::tuple<std::string_view, std::optional<std::string_view>>
+    {
+        return split_once_impl(str, sep);
+    }
+
+    namespace
+    {
+        template <typename Char, typename CharOrStrView>
+        auto rsplit_once_impl(std::basic_string_view<Char> str, CharOrStrView sep)
+            -> std::tuple<std::optional<std::string_view>, std::string_view>
+        {
+            static constexpr auto npos = std::basic_string_view<Char>::npos;
+            if (const auto pos = str.rfind(sep); pos != npos)
+            {
+                return { str.substr(0, pos), str.substr(pos + detail::length(sep)) };
+            }
+            return { std::nullopt, str };
+        }
+    }
+
+    auto rsplit_once(std::string_view str, char sep)
+        -> std::tuple<std::optional<std::string_view>, std::string_view>
+    {
+        return rsplit_once_impl(str, sep);
+    }
+
+    auto rsplit_once(std::string_view str, std::string_view sep)
+        -> std::tuple<std::optional<std::string_view>, std::string_view>
+    {
+        return rsplit_once_impl(str, sep);
+    }
+
+
     /***************************************
      *  Implementation of split functions  *
      ***************************************/

diff --git a/libmamba/tests/src/doctest-printer/optional.hpp b/libmamba/tests/src/doctest-printer/optional.hpp
@@ -0,0 +1,26 @@
+// Copyright (c) 2023, QuantStack and Mamba Contributors
+//
+// Distributed under the terms of the BSD 3-Clause License.
+//
+// The full license is in the file LICENSE, distributed with this software.
+
+#include <optional>
+
+#include <doctest/doctest.h>
+#include <fmt/format.h>
+
+namespace doctest
+{
+    template <typename T>
+    struct StringMaker<std::optional<T>>
+    {
+        static auto convert(const std::optional<T>& value) -> String
+        {
+            if (value.has_value())
+            {
+                return { fmt::format("Some({})", value.value()).c_str() };
+            }
+            return "None";
+        }
+    };
+}
diff --git a/libmamba/tests/src/util/test_string.cpp b/libmamba/tests/src/util/test_string.cpp
@@ -4,7 +4,6 @@
 //
 // The full license is in the file LICENSE, distributed with this software.
 
-#include <cstddef>
 #include <string>
 #include <string_view>
 #include <vector>
@@ -14,6 +13,9 @@
 #include "mamba/fs/filesystem.hpp"
 #include "mamba/util/string.hpp"
 
+#include "doctest-printer/array.hpp"
+#include "doctest-printer/optional.hpp"
+
 namespace mamba::util
 {
     TEST_SUITE("util::string")
@@ -364,6 +366,40 @@ namespace mamba::util
             }
         }
 
+        TEST_CASE("split_once")
+        {
+            using Out = std::tuple<std::string_view, std::optional<std::string_view>>;
+
+            CHECK_EQ(split_once("", '/'), Out{ "", std::nullopt });
+            CHECK_EQ(split_once("/", '/'), Out{ "", "" });
+            CHECK_EQ(split_once("hello/world", '/'), Out{ "hello", "world" });
+            CHECK_EQ(split_once("hello/my/world", '/'), Out{ "hello", "my/world" });
+            CHECK_EQ(split_once("/hello/world", '/'), Out{ "", "hello/world" });
+
+            CHECK_EQ(split_once("", "/"), Out{ "", std::nullopt });
+            CHECK_EQ(split_once("hello/world", "/"), Out{ "hello", "world" });
+            CHECK_EQ(split_once("hello//world", "//"), Out{ "hello", "world" });
+            CHECK_EQ(split_once("hello/my//world", "/"), Out{ "hello", "my//world" });
+            CHECK_EQ(split_once("hello/my//world", "//"), Out{ "hello/my", "world" });
+        }
+
+        TEST_CASE("rsplit_once")
+        {
+            using Out = std::tuple<std::optional<std::string_view>, std::string_view>;
+
+            CHECK_EQ(rsplit_once("", '/'), Out{ std::nullopt, "" });
+            CHECK_EQ(rsplit_once("/", '/'), Out{ "", "" });
+            CHECK_EQ(rsplit_once("hello/world", '/'), Out{ "hello", "world" });
+            CHECK_EQ(rsplit_once("hello/my/world", '/'), Out{ "hello/my", "world" });
+            CHECK_EQ(rsplit_once("hello/world/", '/'), Out{ "hello/world", "" });
+
+            CHECK_EQ(rsplit_once("", "/"), Out{ std::nullopt, "" });
+            CHECK_EQ(rsplit_once("hello/world", "/"), Out{ "hello", "world" });
+            CHECK_EQ(rsplit_once("hello//world", "//"), Out{ "hello", "world" });
+            CHECK_EQ(rsplit_once("hello//my/world", "/"), Out{ "hello//my", "world" });
+            CHECK_EQ(rsplit_once("hello//my/world", "//"), Out{ "hello", "my/world" });
+        }
+
         TEST_CASE("split")
         {
             std::string a = "hello.again.it's.me.mario";