pull: Use internal base64 decoding function to avoid dependency (#417)

.github/scripts/run-prepare

@@ -34,6 +34,6 @@ esac
 
 case "${BUILDSYSTEM_ARG}" in
     cmake)
-        "${VCPKG_INSTALLATION_ROOT}/vcpkg" install benchmark civetweb cppcodec curl gtest zlib
+        "${VCPKG_INSTALLATION_ROOT}/vcpkg" install benchmark civetweb curl gtest zlib
         ;;
 esac

.github/scripts/run-prepare.cmd

@@ -1,4 +1,4 @@
 if [%1] == [cmake] (
-    %VCPKG_INSTALLATION_ROOT%/vcpkg install benchmark civetweb cppcodec curl gtest zlib || EXIT /B 1
+    %VCPKG_INSTALLATION_ROOT%/vcpkg install benchmark civetweb curl gtest zlib || EXIT /B 1
 )
 

.gitmodules

@@ -4,6 +4,3 @@
 [submodule "civetweb"]
 	path = 3rdparty/civetweb
 	url = https://github.com/civetweb/civetweb.git
-[submodule "3rdparty/cppcodec"]
-	path = 3rdparty/cppcodec
-	url = https://github.com/tplgy/cppcodec.git

bazel/cppcodec.BUILD

@@ -1,6 +0,0 @@
-cc_library(
-    name = "cppcodec",
-    hdrs = glob(["cppcodec/**/*.hpp"]),
-    includes = ["."],
-    visibility = ["//visibility:public"],
-)

bazel/repositories.bzl

@@ -45,17 +45,6 @@ def prometheus_cpp_repositories():
         ],
     )
 
-    maybe(
-        http_archive,
-        name = "com_github_tplgy_cppcodec",
-        sha256 = "0edaea2a9d9709d456aa99a1c3e17812ed130f9ef2b5c2d152c230a5cbc5c482",
-        strip_prefix = "cppcodec-0.2",
-        urls = [
-            "https://github.com/tplgy/cppcodec/archive/v0.2.tar.gz",
-        ],
-        build_file = "@com_github_jupp0r_prometheus_cpp//bazel:cppcodec.BUILD",
-    )
-
     maybe(
         http_archive,
         name = "net_zlib_zlib",

cmake/Findcppcodec.cmake

@@ -1,8 +0,0 @@
-find_path(CPPCODEC_INCLUDE_DIR base64_rfc4648.hpp PATH_SUFFIXES include/cppcodec)
-
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(cppcodec DEFAULT_MSG CPPCODEC_INCLUDE_DIR)
-
-if(cppcodec_FOUND)
-  set(CPPCODEC_INCLUDE_DIRS "${CPPCODEC_INCLUDE_DIR}")
-endif()

cmake/cppcodec-3rdparty-config.cmake

@@ -1,14 +0,0 @@
-get_filename_component(_IMPORT_PREFIX "${PROJECT_SOURCE_DIR}/3rdparty/cppcodec/" ABSOLUTE)
-
-macro(set_and_check _var _file)
-  set(${_var} "${_file}")
-  if(NOT EXISTS "${_file}")
-    message(FATAL_ERROR "File or directory ${_file} referenced by variable ${_var} does not exist !")
-  endif()
-endmacro()
-
-set_and_check(CPPCODEC_INCLUDE_DIR ${_IMPORT_PREFIX})
-set(CPPCODEC_INCLUDE_DIRS "${CPPCODEC_INCLUDE_DIR}")
-
-add_library(cppcodec INTERFACE)
-target_include_directories(cppcodec INTERFACE "$<BUILD_INTERFACE:${CPPCODEC_INCLUDE_DIR}>")

pull/BUILD.bazel

@@ -23,7 +23,18 @@ cc_library(
     deps = [
         "//core",
         "@civetweb",
-        "@com_github_tplgy_cppcodec//:cppcodec",
         "@net_zlib_zlib//:z",
     ],
 )
+
+cc_library(
+    name = "pull_internal_headers",
+    hdrs = glob(
+        ["src/detail/*.h"],
+    ),
+    strip_include_prefix = "src",
+    visibility = ["//pull/tests:__subpackages__"],
+    deps = [
+        "//core",
+    ],
+)

pull/CMakeLists.txt

@@ -5,15 +5,8 @@ if(USE_THIRDPARTY_LIBRARIES)
     TARGETS civetweb
     EXPORT ${PROJECT_NAME}-targets
   )
-  find_package(cppcodec-3rdparty CONFIG REQUIRED)
-  add_library(${PROJECT_NAME}::cppcodec ALIAS cppcodec)
-  install(
-    TARGETS cppcodec
-    EXPORT ${PROJECT_NAME}-targets
-  )
 else()
   find_package(civetweb CONFIG REQUIRED)
-  find_package(cppcodec REQUIRED)
 
   # work-around https://github.com/civetweb/civetweb/pull/918
   if(WIN32 AND NOT TARGET WINSOCK::WINSOCK)
@@ -36,6 +29,8 @@ add_library(pull
   src/handler.h
   src/metrics_collector.cc
   src/metrics_collector.h
+
+  src/detail/base64.h
 )
 
 add_library(${PROJECT_NAME}::pull ALIAS pull)
@@ -46,7 +41,6 @@ target_link_libraries(pull
   PRIVATE
     Threads::Threads
     $<IF:$<BOOL:${USE_THIRDPARTY_LIBRARIES}>,${PROJECT_NAME}::civetweb,civetweb::civetweb-cpp>
-    $<$<BOOL:${USE_THIRDPARTY_LIBRARIES}>:${PROJECT_NAME}::cppcodec>
     $<$<AND:$<BOOL:UNIX>,$<NOT:$<BOOL:APPLE>>>:rt>
     $<$<BOOL:${ENABLE_COMPRESSION}>:ZLIB::ZLIB>
 )
@@ -56,7 +50,6 @@ target_include_directories(pull
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
     $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>
   PRIVATE
-    ${CPPCODEC_INCLUDE_DIRS} # needed as long as upstream cppcodec installs no config file with imported target
     ${CIVETWEB_INCLUDE_DIRS}
 )
 
@@ -93,5 +86,9 @@ install(
 )
 
 if(ENABLE_TESTING)
+  add_library(pull_internal_headers INTERFACE)
+  add_library(${PROJECT_NAME}::pull_internal_headers ALIAS pull_internal_headers)
+  target_include_directories(pull_internal_headers INTERFACE src)
+
   add_subdirectory(tests)
 endif()

pull/src/basic_auth.cc

@@ -1,14 +1,11 @@
 #include "basic_auth.h"
 
-#include <cppcodec/base64_rfc4648.hpp>
-
 #include "CivetServer.h"
+#include "detail/base64.h"
 #include "prometheus/detail/future_std.h"
 
 namespace prometheus {
 
-using base64 = cppcodec::base64_rfc4648;
-
 BasicAuthHandler::BasicAuthHandler(AuthFunc callback, std::string realm)
     : callback_(std::move(callback)), realm_(std::move(realm)) {}
 
@@ -42,7 +39,7 @@ bool BasicAuthHandler::AuthorizeInner(CivetServer*, mg_connection* conn) {
 
   std::string decoded;
   try {
-    decoded = base64::decode<std::string>(b64Auth.data(), b64Auth.size());
+    decoded = detail::base64_decode(b64Auth);
   } catch (...) {
     return false;
   }

pull/src/detail/base64.h

@@ -0,0 +1,88 @@
+#pragma once
+
+#include <cstdint>
+#include <stdexcept>
+#include <string>
+
+namespace prometheus {
+namespace detail {
+
+/*
+Copyright (C) 2019-2020 by Martin Vorbrodt <martin@vorbrodt.blog>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+
+https://github.com/mvorbrodt/blog/blob/master/src/base64.hpp
+*/
+
+inline std::string base64_decode(const std::string& input) {
+  const char kPadCharacter = '=';
+
+  if (input.length() % 4) {
+    throw std::runtime_error("Invalid base64 length!");
+  }
+
+  std::size_t padding = 0;
+
+  if (!input.empty()) {
+    if (input[input.length() - 1] == kPadCharacter) padding++;
+    if (input[input.length() - 2] == kPadCharacter) padding++;
+  }
+
+  std::string decoded;
+  decoded.reserve(((input.length() / 4) * 3) - padding);
+
+  std::uint32_t temp = 0;
+  auto it = input.begin();
+
+  while (it < input.end()) {
+    for (std::size_t i = 0; i < 4; ++i) {
+      temp <<= 6;
+      if (*it >= 0x41 && *it <= 0x5A) {
+        temp |= *it - 0x41;
+      } else if (*it >= 0x61 && *it <= 0x7A) {
+        temp |= *it - 0x47;
+      } else if (*it >= 0x30 && *it <= 0x39) {
+        temp |= *it + 0x04;
+      } else if (*it == 0x2B) {
+        temp |= 0x3E;
+      } else if (*it == 0x2F) {
+        temp |= 0x3F;
+      } else if (*it == kPadCharacter) {
+        switch (input.end() - it) {
+          case 1:
+            decoded.push_back((temp >> 16) & 0x000000FF);
+            decoded.push_back((temp >> 8) & 0x000000FF);
+            return decoded;
+          case 2:
+            decoded.push_back((temp >> 10) & 0x000000FF);
+            return decoded;
+          default:
+            throw std::runtime_error("Invalid padding in base64!");
+        }
+      } else {
+        throw std::runtime_error("Invalid character in base64!");
+      }
+
+      ++it;
+    }
+
+    decoded.push_back((temp >> 16) & 0x000000FF);
+    decoded.push_back((temp >> 8) & 0x000000FF);
+    decoded.push_back((temp)&0x000000FF);
+  }
+
+  return decoded;
+}
+
+}  // namespace detail
+}  // namespace prometheus

pull/tests/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(integration)
+add_subdirectory(internal)
 add_subdirectory(unit)

pull/tests/internal/BUILD.bazel

@@ -0,0 +1,13 @@
+cc_test(
+    name = "internal",
+    srcs = glob([
+        "*.cc",
+        "*.h",
+    ]),
+    copts = ["-Iexternal/googletest/include"],
+    linkstatic = True,
+    deps = [
+        "//pull:pull_internal_headers",
+        "@com_google_googletest//:gtest_main",
+    ],
+)

pull/tests/internal/CMakeLists.txt

@@ -0,0 +1,14 @@
+add_executable(prometheus_pull_internal_test
+  base64_test.cc
+)
+
+target_link_libraries(prometheus_pull_internal_test
+  PRIVATE
+    ${PROJECT_NAME}::pull_internal_headers
+    GTest::gmock_main
+)
+
+add_test(
+  NAME prometheus_pull_internal_test
+  COMMAND prometheus_pull_internal_test
+)

pull/tests/internal/base64_test.cc

@@ -0,0 +1,49 @@
+#include "detail/base64.h"
+
+#include <gtest/gtest.h>
+
+#include <string>
+
+namespace prometheus {
+namespace {
+
+struct TestVector {
+  const std::string decoded;
+  const std::string encoded;
+};
+
+const TestVector testVector[] = {
+    {"", ""},
+    {"f", "Zg=="},
+    {"fo", "Zm8="},
+    {"foo", "Zm9v"},
+    {"foob", "Zm9vYg=="},
+    {"fooba", "Zm9vYmE="},
+    {"foobar", "Zm9vYmFy"},
+};
+
+const unsigned nVectors = sizeof(testVector) / sizeof(testVector[0]);
+
+using namespace testing;
+
+TEST(Base64Test, decodeTest) {
+  for (unsigned i = 0; i < nVectors; ++i) {
+    std::string decoded = detail::base64_decode(testVector[i].encoded);
+    EXPECT_EQ(testVector[i].decoded, decoded);
+  }
+}
+
+TEST(Base64Test, rejectInvalidSymbols) {
+  EXPECT_ANY_THROW(detail::base64_decode("...."));
+}
+
+TEST(Base64Test, rejectInvalidInputSize) {
+  EXPECT_ANY_THROW(detail::base64_decode("ABC"));
+}
+
+TEST(Base64Test, rejectInvalidPadding) {
+  EXPECT_ANY_THROW(detail::base64_decode("A==="));
+}
+
+}  // namespace
+}  // namespace prometheus