From 5d268488b2861ce73db233d71bdb527f89001a4e Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sat, 25 Jan 2025 12:57:24 +0100
Subject: Add PointerList class for working with, and propagating, argc/argv

---
 src/pointerlist.cc       | 28 +++++++++++++++
 src/pointerlist.h        | 26 ++++++++++++++
 test/ctor.cc             | 17 +++++++++
 test/pointerlist_test.cc | 90 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 161 insertions(+)
 create mode 100644 src/pointerlist.cc
 create mode 100644 src/pointerlist.h
 create mode 100644 test/pointerlist_test.cc

diff --git a/src/pointerlist.cc b/src/pointerlist.cc
new file mode 100644
index 0000000..e642075
--- /dev/null
+++ b/src/pointerlist.cc
@@ -0,0 +1,28 @@
+// -*- c++ -*-
+// Distributed under the BSD 2-Clause License.
+// See accompanying file LICENSE for details.
+#include "pointerlist.h"
+
+PointerList::PointerList(int argc, const char* argv[])
+{
+	for(int i = 0; i < argc; ++i)
+	{
+		push_back(argv[i]);
+	}
+}
+
+std::pair<int, const char**> PointerList::get()
+{
+	argptrs.clear();
+	for(const auto& arg : *this)
+	{
+		argptrs.push_back(arg.data());
+	}
+
+	if(argptrs.size() == 0)
+	{
+		return {0, nullptr};
+	}
+
+	return {argptrs.size(), argptrs.data()};
+}
diff --git a/src/pointerlist.h b/src/pointerlist.h
new file mode 100644
index 0000000..7c51ca6
--- /dev/null
+++ b/src/pointerlist.h
@@ -0,0 +1,26 @@
+// -*- c++ -*-
+// Distributed under the BSD 2-Clause License.
+// See accompanying file LICENSE for details.
+
+#include <string>
+#include <vector>
+#include <deque>
+#include <utility>
+
+// Maintains an (owning) list of string args and converts them to argc/argv
+// compatible arguments on request.
+// The returned pointers are guaranteed to be valid as long as the PointerList
+// object lifetime is not exceeded.
+class PointerList :
+	public std::deque<std::string>
+{
+public:
+	PointerList() = default;
+	PointerList(int argc, const char* argv[]);
+
+	//! Returns argc/argv pair from the current list of args
+	std::pair<int, const char**> get();
+
+private:
+	std::vector<const char*> argptrs;
+};
diff --git a/test/ctor.cc b/test/ctor.cc
index d69b1cf..acb232f 100644
--- a/test/ctor.cc
+++ b/test/ctor.cc
@@ -9,6 +9,23 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 {
 	return
 	{
+		{
+			.type = ctor::target_type::unit_test,
+			.system = ctor::output_system::build,
+			.target = "pointerlist_test",
+			.sources = {
+				"pointerlist_test.cc",
+				"testmain.cc",
+				"../src/pointerlist.cc",
+			},
+			.flags = {
+				.cxxflags = {
+					"-std=c++20", "-O3", "-Wall", "-Werror",
+					"-I../src", "-Iuunit",
+					"-DOUTPUT=\"pointerlist\"",
+				},
+			},
+		},
 		{
 			.type = ctor::target_type::unit_test,
 			.system = ctor::output_system::build,
diff --git a/test/pointerlist_test.cc b/test/pointerlist_test.cc
new file mode 100644
index 0000000..329e319
--- /dev/null
+++ b/test/pointerlist_test.cc
@@ -0,0 +1,90 @@
+// -*- c++ -*-
+// Distributed under the BSD 2-Clause License.
+// See accompanying file LICENSE for details.
+#include <uunit.h>
+
+#include "pointerlist.h"
+
+class PointerListTest
+	: public uUnit
+{
+public:
+	PointerListTest()
+	{
+		uTEST(PointerListTest::test_zom_push);
+		uTEST(PointerListTest::test_zom_from_args);
+	}
+
+	void test_zom_push()
+	{
+		using namespace std::string_literals;
+
+		{ // Zero
+			PointerList args;
+			uASSERT_EQUAL(0u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(0, argc);
+			uASSERT_EQUAL(nullptr, argv);
+		}
+
+		{ // One
+			PointerList args;
+			args.push_back("hello");
+			uASSERT_EQUAL(1u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(1, argc);
+			uASSERT_EQUAL("hello"s, std::string(argv[0]));
+		}
+
+		{ // Many
+			PointerList args;
+			args.push_back("hello");
+			args.push_back("dear");
+			args.push_back("world");
+			uASSERT_EQUAL(3u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(3, argc);
+			uASSERT_EQUAL("hello"s, std::string(argv[0]));
+			uASSERT_EQUAL("dear"s, std::string(argv[1]));
+			uASSERT_EQUAL("world"s, std::string(argv[2]));
+		}
+	}
+
+	void test_zom_from_args()
+	{
+		using namespace std::string_literals;
+
+		{ // Zero
+			PointerList args(0, nullptr);
+			uASSERT_EQUAL(0u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(0, argc);
+			uASSERT_EQUAL(nullptr, argv);
+		}
+
+		{ // One
+			int _argc{1};
+			const char* _argv[] = { "hello" };
+			PointerList args(_argc, _argv);
+			uASSERT_EQUAL(1u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(1, argc);
+			uASSERT_EQUAL("hello"s, std::string(argv[0]));
+		}
+
+		{ // Many
+			int _argc{3};
+			const char* _argv[] = { "hello", "dear", "world" };
+			PointerList args(_argc, _argv);
+			uASSERT_EQUAL(3u, args.size());
+			auto [argc, argv] = args.get();
+			uASSERT_EQUAL(3, argc);
+			uASSERT_EQUAL("hello"s, std::string(argv[0]));
+			uASSERT_EQUAL("dear"s, std::string(argv[1]));
+			uASSERT_EQUAL("world"s, std::string(argv[2]));
+		}
+	}
+};
+
+// Registers the fixture into the 'registry'
+static PointerListTest test;
-- 
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