Introduce cmArgumentParser

7 files changed, 389 insertions, 0 deletions

diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index 52f6742..a2836d6 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -143,6 +143,8 @@ set(SRCS
   cmAffinity.cxx
   cmAffinity.h
   cmArchiveWrite.cxx
+  cmArgumentParser.cxx
+  cmArgumentParser.h
   cmBase32.cxx
   cmCacheManager.cxx
   cmCacheManager.h
diff --git a/Source/cmArgumentParser.cxx b/Source/cmArgumentParser.cxx
new file mode 100644
index 0000000..9a9932c
--- /dev/null
+++ b/Source/cmArgumentParser.cxx
@@ -0,0 +1,93 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmArgumentParser.h"
+
+#include <algorithm>
+#include <type_traits>
+
+namespace ArgumentParser {
+
+auto ActionMap::Emplace(cm::string_view name, Action action)
+  -> std::pair<iterator, bool>
+{
+  auto const it =
+    std::lower_bound(this->begin(), this->end(), name,
+                     [](value_type const& elem, cm::string_view const& k) {
+                       return elem.first < k;
+                     });
+  return (it != this->end() && it->first == name)
+    ? std::make_pair(it, false)
+    : std::make_pair(this->emplace(it, name, std::move(action)), true);
+}
+
+auto ActionMap::Find(cm::string_view name) const -> const_iterator
+{
+  auto const it =
+    std::lower_bound(this->begin(), this->end(), name,
+                     [](value_type const& elem, cm::string_view const& k) {
+                       return elem.first < k;
+                     });
+  return (it != this->end() && it->first == name) ? it : this->end();
+}
+
+void Instance::Bind(bool& val)
+{
+  val = true;
+  this->CurrentString = nullptr;
+  this->CurrentList = nullptr;
+  this->ExpectValue = false;
+}
+
+void Instance::Bind(std::string& val)
+{
+  this->CurrentString = &val;
+  this->CurrentList = nullptr;
+  this->ExpectValue = true;
+}
+
+void Instance::Bind(StringList& val)
+{
+  this->CurrentString = nullptr;
+  this->CurrentList = &val;
+  this->ExpectValue = true;
+}
+
+void Instance::Bind(MultiStringList& val)
+{
+  this->CurrentString = nullptr;
+  this->CurrentList = (val.emplace_back(), &val.back());
+  this->ExpectValue = false;
+}
+
+void Instance::Consume(cm::string_view arg, void* result,
+                       std::vector<std::string>* unparsedArguments,
+                       std::vector<std::string>* keywordsMissingValue)
+{
+  auto const it = this->Bindings.Find(arg);
+  if (it != this->Bindings.end()) {
+    it->second(*this, result);
+    if (this->ExpectValue && keywordsMissingValue != nullptr) {
+      keywordsMissingValue->emplace_back(arg);
+    }
+    return;
+  }
+
+  if (this->CurrentString != nullptr) {
+    this->CurrentString->assign(std::string(arg));
+    this->CurrentString = nullptr;
+    this->CurrentList = nullptr;
+  } else if (this->CurrentList != nullptr) {
+    this->CurrentList->emplace_back(arg);
+  } else if (unparsedArguments != nullptr) {
+    unparsedArguments->emplace_back(arg);
+  }
+
+  if (this->ExpectValue) {
+    if (keywordsMissingValue != nullptr) {
+      keywordsMissingValue->pop_back();
+    }
+    this->ExpectValue = false;
+  }
+}
+
+} // namespace ArgumentParser
diff --git a/Source/cmArgumentParser.h b/Source/cmArgumentParser.h
new file mode 100644
index 0000000..6cfe946
--- /dev/null
+++ b/Source/cmArgumentParser.h
@@ -0,0 +1,143 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmArgumentParser_h
+#define cmArgumentParser_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include "cm_static_string_view.hxx"
+#include "cm_string_view.hxx"
+
+#include <cassert>
+#include <functional>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace ArgumentParser {
+
+using StringList = std::vector<std::string>;
+using MultiStringList = std::vector<StringList>;
+
+class Instance;
+using Action = std::function<void(Instance&, void*)>;
+
+// using ActionMap = cm::flat_map<cm::string_view, Action>;
+class ActionMap : public std::vector<std::pair<cm::string_view, Action>>
+{
+public:
+  std::pair<iterator, bool> Emplace(cm::string_view name, Action action);
+  const_iterator Find(cm::string_view name) const;
+};
+
+class Instance
+{
+public:
+  Instance(ActionMap const& bindings)
+    : Bindings(bindings)
+  {
+  }
+
+  void Bind(bool& val);
+  void Bind(std::string& val);
+  void Bind(StringList& val);
+  void Bind(MultiStringList& val);
+
+  void Consume(cm::string_view arg, void* result,
+               std::vector<std::string>* unparsedArguments,
+               std::vector<std::string>* keywordsMissingValue);
+
+private:
+  ActionMap const& Bindings;
+  std::string* CurrentString = nullptr;
+  StringList* CurrentList = nullptr;
+  bool ExpectValue = false;
+};
+
+} // namespace ArgumentParser
+
+template <typename Result>
+class cmArgumentParser
+{
+public:
+  // I *think* this function could be made `constexpr` when the code is
+  // compiled as C++20.  This would allow building a parser at compile time.
+  template <typename T>
+  cmArgumentParser& Bind(cm::static_string_view name, T Result::*member)
+  {
+    bool const inserted =
+      this->Bindings
+        .Emplace(name,
+                 [member](ArgumentParser::Instance& instance, void* result) {
+                   instance.Bind(static_cast<Result*>(result)->*member);
+                 })
+        .second;
+    assert(inserted), (void)inserted;
+    return *this;
+  }
+
+  template <typename Range>
+  void Parse(Result& result, Range const& args,
+             std::vector<std::string>* unparsedArguments = nullptr,
+             std::vector<std::string>* keywordsMissingValue = nullptr) const
+  {
+    ArgumentParser::Instance instance(this->Bindings);
+    for (cm::string_view arg : args) {
+      instance.Consume(arg, &result, unparsedArguments, keywordsMissingValue);
+    }
+  }
+
+  template <typename Range>
+  Result Parse(Range const& args,
+               std::vector<std::string>* unparsedArguments = nullptr,
+               std::vector<std::string>* keywordsMissingValue = nullptr) const
+  {
+    Result result;
+    this->Parse(result, args, unparsedArguments, keywordsMissingValue);
+    return result;
+  }
+
+private:
+  ArgumentParser::ActionMap Bindings;
+};
+
+template <>
+class cmArgumentParser<void>
+{
+public:
+  template <typename T>
+  cmArgumentParser& Bind(cm::static_string_view name, T& ref)
+  {
+    bool const inserted = this->Bind(cm::string_view(name), ref);
+    assert(inserted), (void)inserted;
+    return *this;
+  }
+
+  template <typename Range>
+  void Parse(Range const& args,
+             std::vector<std::string>* unparsedArguments = nullptr,
+             std::vector<std::string>* keywordsMissingValue = nullptr) const
+  {
+    ArgumentParser::Instance instance(this->Bindings);
+    for (cm::string_view arg : args) {
+      instance.Consume(arg, nullptr, unparsedArguments, keywordsMissingValue);
+    }
+  }
+
+protected:
+  template <typename T>
+  bool Bind(cm::string_view name, T& ref)
+  {
+    return this->Bindings
+      .Emplace(name,
+               [&ref](ArgumentParser::Instance& instance, void*) {
+                 instance.Bind(ref);
+               })
+      .second;
+  }
+
+private:
+  ArgumentParser::ActionMap Bindings;
+};
+
+#endif
diff --git a/Tests/CMakeLib/CMakeLists.txt b/Tests/CMakeLib/CMakeLists.txt
index 91f7e25..031ab01 100644
--- a/Tests/CMakeLib/CMakeLists.txt
+++ b/Tests/CMakeLib/CMakeLists.txt
@@ -5,6 +5,7 @@ include_directories(
   )
 
 set(CMakeLib_TESTS
+  testArgumentParser.cxx
   testGeneratedFileStream.cxx
   testRST.cxx
   testRange.cxx
diff --git a/Tests/CMakeLib/testArgumentParser.cxx b/Tests/CMakeLib/testArgumentParser.cxx
new file mode 100644
index 0000000..788fece
--- /dev/null
+++ b/Tests/CMakeLib/testArgumentParser.cxx
@@ -0,0 +1,148 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#include "cmArgumentParser.h"
+
+#include "cm_static_string_view.hxx"
+#include "cm_string_view.hxx"
+
+#include <initializer_list>
+#include <iostream>
+#include <string>
+#include <vector>
+
+namespace {
+
+struct Result
+{
+  bool Option1 = false;
+  bool Option2 = false;
+
+  std::string String1;
+  std::string String2;
+
+  std::vector<std::string> List1;
+  std::vector<std::string> List2;
+  std::vector<std::string> List3;
+
+  std::vector<std::vector<std::string>> Multi1;
+  std::vector<std::vector<std::string>> Multi2;
+  std::vector<std::vector<std::string>> Multi3;
+};
+
+std::initializer_list<cm::string_view> const args = {
+  /* clang-format off */
+  "OPTION_1",                // option
+  "STRING_1",                // string arg missing value
+  "STRING_2", "foo", "bar",  // string arg + unparsed value
+  "LIST_1",                  // list arg missing values
+  "LIST_2", "foo", "bar",    // list arg with 2 elems
+  "LIST_3", "bar",           // list arg ...
+  "LIST_3", "foo",           // ... with continuation
+  "MULTI_2",                 // multi list with 0 lists
+  "MULTI_3", "foo", "bar",   // multi list with first list with two elems
+  "MULTI_3", "bar", "foo",   // multi list with second list with two elems
+  /* clang-format on */
+};
+
+bool verifyResult(Result const& result,
+                  std::vector<std::string> const& unparsedArguments,
+                  std::vector<std::string> const& keywordsMissingValue)
+{
+  static std::vector<std::string> const foobar = { "foo", "bar" };
+  static std::vector<std::string> const barfoo = { "bar", "foo" };
+  static std::vector<std::string> const missing = { "STRING_1", "LIST_1" };
+
+#define ASSERT_TRUE(x)                                                        \
+  do {                                                                        \
+    if (!(x)) {                                                               \
+      std::cout << "ASSERT_TRUE(" #x ") failed on line " << __LINE__ << "\n"; \
+      return false;                                                           \
+    }                                                                         \
+  } while (false)
+
+  ASSERT_TRUE(result.Option1);
+  ASSERT_TRUE(!result.Option2);
+
+  ASSERT_TRUE(result.String1.empty());
+  ASSERT_TRUE(result.String2 == "foo");
+
+  ASSERT_TRUE(result.List1.empty());
+  ASSERT_TRUE(result.List2 == foobar);
+  ASSERT_TRUE(result.List3 == barfoo);
+
+  ASSERT_TRUE(result.Multi1.empty());
+  ASSERT_TRUE(result.Multi2.size() == 1);
+  ASSERT_TRUE(result.Multi2[0].empty());
+  ASSERT_TRUE(result.Multi3.size() == 2);
+  ASSERT_TRUE(result.Multi3[0] == foobar);
+  ASSERT_TRUE(result.Multi3[1] == barfoo);
+
+  ASSERT_TRUE(unparsedArguments.size() == 1);
+  ASSERT_TRUE(unparsedArguments[0] == "bar");
+  ASSERT_TRUE(keywordsMissingValue == missing);
+
+  return true;
+}
+
+bool testArgumentParserDynamic()
+{
+  Result result;
+  std::vector<std::string> unparsedArguments;
+  std::vector<std::string> keywordsMissingValue;
+
+  cmArgumentParser<void>{}
+    .Bind("OPTION_1"_s, result.Option1)
+    .Bind("OPTION_2"_s, result.Option2)
+    .Bind("STRING_1"_s, result.String1)
+    .Bind("STRING_2"_s, result.String2)
+    .Bind("LIST_1"_s, result.List1)
+    .Bind("LIST_2"_s, result.List2)
+    .Bind("LIST_3"_s, result.List3)
+    .Bind("MULTI_1"_s, result.Multi1)
+    .Bind("MULTI_2"_s, result.Multi2)
+    .Bind("MULTI_3"_s, result.Multi3)
+    .Parse(args, &unparsedArguments, &keywordsMissingValue);
+
+  return verifyResult(result, unparsedArguments, keywordsMissingValue);
+}
+
+bool testArgumentParserStatic()
+{
+  static auto const parser = //
+    cmArgumentParser<Result>{}
+      .Bind("OPTION_1"_s, &Result::Option1)
+      .Bind("OPTION_2"_s, &Result::Option2)
+      .Bind("STRING_1"_s, &Result::String1)
+      .Bind("STRING_2"_s, &Result::String2)
+      .Bind("LIST_1"_s, &Result::List1)
+      .Bind("LIST_2"_s, &Result::List2)
+      .Bind("LIST_3"_s, &Result::List3)
+      .Bind("MULTI_1"_s, &Result::Multi1)
+      .Bind("MULTI_2"_s, &Result::Multi2)
+      .Bind("MULTI_3"_s, &Result::Multi3);
+
+  std::vector<std::string> unparsedArguments;
+  std::vector<std::string> keywordsMissingValue;
+  Result const result =
+    parser.Parse(args, &unparsedArguments, &keywordsMissingValue);
+
+  return verifyResult(result, unparsedArguments, keywordsMissingValue);
+}
+
+} // namespace
+
+int testArgumentParser(int /*unused*/, char* /*unused*/ [])
+{
+  if (!testArgumentParserDynamic()) {
+    std::cout << "While executing testArgumentParserDynamic().\n";
+    return -1;
+  }
+
+  if (!testArgumentParserStatic()) {
+    std::cout << "While executing testArgumentParserStatic().\n";
+    return -1;
+  }
+
+  return 0;
+}
diff --git a/Utilities/IWYU/mapping.imp b/Utilities/IWYU/mapping.imp
index 482a08d..0393ff1 100644
--- a/Utilities/IWYU/mapping.imp
+++ b/Utilities/IWYU/mapping.imp
@@ -68,6 +68,7 @@
   { symbol: [ "std::__decay_and_strip<cmGeneratorTarget *&>::__type", private, "\"cmConfigure.h\"", public ] },
   { symbol: [ "std::__decay_and_strip<cmFindCommon::PathLabel &>::__type", private, "\"cmConfigure.h\"", public ] },
   { symbol: [ "std::__decay_and_strip<cmSearchPath>::__type", private, "\"cmConfigure.h\"", public ] },
+  { symbol: [ "std::__decay_and_strip<cm::string_view>::__type", private, "\"cmConfigure.h\"", public ] },
   { symbol: [ "std::__decay_and_strip<std::basic_string<char> &>::__type", private, "\"cmConfigure.h\"", public ] },
   { symbol: [ "std::__decay_and_strip<const std::basic_string<char> &>::__type", private, "\"cmConfigure.h\"", public ] },
   { symbol: [ "std::__decay_and_strip<cmFindPackageCommand::PathLabel &>::__type", private, "\"cmConfigure.h\"", public ] },
diff --git a/bootstrap b/bootstrap
index 537b43b..addb4f7 100755
--- a/bootstrap
+++ b/bootstrap
@@ -260,6 +260,7 @@ CMAKE_CXX_SOURCES="\
   cmAddLibraryCommand \
   cmAddSubDirectoryCommand \
   cmAddTestCommand \
+  cmArgumentParser \
   cmBreakCommand \
   cmBuildCommand \
   cmCMakeMinimumRequired \