Update to latest google3 version

* Use absl::flags and absl::log instead of gflags/glog
* Use ABSL_UNREACHABLE, requires abseil/abseil-cpp@6a87605
* New edge/circle intersection ordering predicates
* New functions `GetUVCoordOfEdge` and `GetIJCoordOfEdge`
* S2PolylineAlignment: Use Norm instead of Norm2
* S2Polygon::DestructiveUnion: Use priority_queue internally
* Update CONTRIBUTING.md with more detailed instructions
* Replace `const char *` with `absl::string_view`
* Replace most `gtl::dense_hash_set` uses with `absl::flat_hash_set`
* Replace most `std::set` and `std::map` with `absl::flat_hash_set`
  and `flat_hash_map`

Author: jmr

CMakeLists.txt

@@ -27,15 +27,6 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/third_party/cmake")
 
-option(WITH_GFLAGS "Use gflags to change command line flags." OFF)
-add_feature_info(GFLAGS WITH_GFLAGS
-                 "allows changing command line flags.")
-
-# glog option can only be turned on if gflags is on.
-cmake_dependent_option(WITH_GLOG "Use glog for logging." ON
-                       "WITH_GFLAGS" OFF)
-add_feature_info(GLOG WITH_GLOG "provides logging configurability.")
-
 option(BUILD_SHARED_LIBS "Build shared libraries instead of static." ON)
 add_feature_info(SHARED_LIBS BUILD_SHARED_LIBS
                  "builds shared libraries instead of static.")
@@ -52,26 +43,8 @@ add_feature_info(S2_USE_SYSTEM_INCLUDES S2_USE_SYSTEM_INCLUDES
 
 feature_summary(WHAT ALL)
 
-if (WITH_GLOG)
-    find_package(Glog REQUIRED)
-    # FindGFlags.cmake and FindGlog.cmake do not seem to implement REQUIRED;
-    # check manually.
-    if (NOT ${GLOG_FOUND})
-        message(FATAL_ERROR "Glog requested but not found")
-    endif()
-    add_definitions(-DS2_USE_GLOG)
-else()
-    # Don't output anything for LOG(INFO).
-    add_definitions(-DABSL_MIN_LOG_LEVEL=1)
-endif()
-
-if (WITH_GFLAGS)
-    find_package(GFlags REQUIRED)
-    if (NOT ${GFLAGS_FOUND})
-        message(FATAL_ERROR "GFlags requested but not found")
-    endif()
-    add_definitions(-DS2_USE_GFLAGS)
-endif()
+# Don't output anything for LOG(INFO).
+add_definitions(-DABSL_MIN_LOG_LEVEL=1)
 
 # If we already have abseil we don't need to find it, for an example:
 # add_subdirectory(absl-submbodule)
@@ -111,8 +84,7 @@ endif()
 # If OpenSSL is installed in a non-standard location, configure with
 # something like:
 # OPENSSL_ROOT_DIR=/usr/local/opt/openssl cmake ..
-include_directories(
-    ${GFLAGS_INCLUDE_DIRS} ${GLOG_INCLUDE_DIRS} ${OPENSSL_INCLUDE_DIR})
+include_directories(${OPENSSL_INCLUDE_DIR})
 
 if (WITH_PYTHON)
     include_directories(${Python3_INCLUDE_DIRS})
@@ -213,7 +185,6 @@ add_library(s2
             src/s2/s2text_format.cc
             src/s2/s2wedge_relations.cc
             src/s2/s2winding_operation.cc
-            src/s2/strings/serialize.cc
             src/s2/util/bits/bit-interleave.cc
             src/s2/util/coding/coder.cc
             src/s2/util/coding/varint.cc
@@ -231,19 +202,22 @@ endif()
 
 target_link_libraries(
     s2
-    ${GFLAGS_LIBRARIES} ${GLOG_LIBRARIES} ${OPENSSL_LIBRARIES}
+    ${OPENSSL_LIBRARIES}
     absl::base
     absl::btree
+    absl::check
     absl::config
     absl::core_headers
     absl::dynamic_annotations
     absl::endian
     absl::fixed_array
+    absl::flags
     absl::flat_hash_map
     absl::flat_hash_set
     absl::hash
     absl::inlined_vector
     absl::int128
+    absl::log
     absl::log_severity
     absl::memory
     absl::span
@@ -257,7 +231,9 @@ target_link_libraries(
 if (GOOGLETEST_ROOT)
   target_link_libraries(
       s2testing
-      ${GFLAGS_LIBRARIES} ${GLOG_LIBRARIES}
+      absl::check
+      absl::flags
+      absl::log
       absl::memory
       absl::strings)
 endif()
@@ -415,6 +391,8 @@ install(FILES src/s2/base/casts.h
               src/s2/base/port.h
               src/s2/base/spinlock.h
         DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/s2/base")
+install(FILES src/s2/testing/gtest_prod.h
+	DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/s2/testing")
 install(FILES src/s2/util/bitmap/bitmap.h
         DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/s2/util/bitmap")
 install(FILES src/s2/util/bits/bits.h
@@ -581,8 +559,11 @@ if (GOOGLETEST_ROOT)
         s2testing s2
         absl::base
         absl::btree
+        absl::check
         absl::core_headers
+        absl::flags
         absl::flags_reflection
+        absl::log
         absl::memory
         absl::span
         absl::status

CONTRIBUTING.md

@@ -47,19 +47,28 @@ of your first [pull request][].
      separate branches in order to ensure that a pull request only includes the
      commits related to that bug or feature.
 
-  1. Do your best to have [well-formed commit messages][] for each change.
-     This provides consistency throughout the project, and ensures that commit
-     messages are able to be formatted properly by various git tools.
+  1. Do your best to have [well-formed commit messages][] with a [good
+     description][] for each change.  This provides consistency throughout
+     the project, and ensures that commit messages are able to be formatted
+     properly by various git tools.
+
+  1. Keep PRs [small and focused][] on a single issue.  Do not make unrelated
+     changes in the same PR "because you're there"; this includes reformatting
+     of code, whether automatically or manually.
 
   1. Finally, push the commits to your fork and submit a [pull request][].
 
 [forking]: https://help.github.com/articles/fork-a-repo
 [well-formed commit messages]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
+[good description]: https://google.github.io/eng-practices/review/developer/cl-descriptions.html
 [pull request]: https://help.github.com/articles/creating-a-pull-request
+[small and focused]: https://google.github.io/eng-practices/review/developer/small-cls.html
 
 
 ## Style ##
 
-Contributions should follow the [Google C++ Style Guide].
+Contributions should follow the [Google C++ Style Guide].  Code may be
+[formatted] with `git clang-format`.
 
 [Google C++ Style Guide]: http://google.github.io/styleguide/cppguide.html
+[formatted]: http://google.github.io/styleguide/cppguide.html#Formatting

README.md

@@ -1,7 +1,5 @@
 # S2 Geometry Library
 
-[![Build Status](https://travis-ci.org/google/s2geometry.svg?branch=master)](https://travis-ci.org/google/s2geometry)
-
 ## Overview
 
 This is a package for manipulating geometric shapes. Unlike many geometry
@@ -33,15 +31,13 @@ complete functionality.
 * A C++ compiler with C++14 support, such as [g++ >= 5](https://gcc.gnu.org/)
 * [Abseil](https://github.com/abseil/abseil-cpp) (standard library extensions)
 * [OpenSSL](https://github.com/openssl/openssl) (for its bignum library)
-* [gflags command line flags](https://github.com/gflags/gflags), optional
-* [glog logging module](https://github.com/google/glog), optional
 * [googletest testing framework >= 1.10](https://github.com/google/googletest)
   (to build tests and example programs, optional)
 
 On Ubuntu, all of these other than abseil can be installed via apt-get:
 
 ```
-sudo apt-get install cmake libgflags-dev libgoogle-glog-dev googletest libssl-dev
+sudo apt-get install cmake googletest libssl-dev
 ```
 
 Otherwise, you may need to install some from source.
@@ -54,7 +50,7 @@ On macOS, use [MacPorts](http://www.macports.org/) or
 [Homebrew](http://brew.sh/).  For MacPorts:
 
 ```
-sudo port install cmake gflags google-glog openssl
+sudo port install cmake openssl
 ```
 
 Do not install `gtest` from MacPorts; instead download [release
@@ -116,8 +112,6 @@ sudo make install
 
 On macOS, `sysctl -n hw.logicalcpu` is the equivalent of `nproc`.
 
-Enable gflags and glog with `cmake -DWITH_GFLAGS=ON -DWITH_GLOG=ON ...`.
-
 Disable building of shared libraries with `-DBUILD_SHARED_LIBS=OFF`.
 
 Enable the python interface with `-DWITH_PYTHON=ON`.

src/s2/base/casts.h

@@ -30,6 +30,8 @@
 #include <type_traits>
 
 #include "absl/base/casts.h"  // IWYU pragma: keep
+#include "absl/base/config.h"
+#include "absl/log/log.h"
 
 #include "s2/base/logging.h"
 
@@ -63,8 +65,8 @@ inline To down_cast(From* f) {         // so we only accept pointers
   static_assert((std::is_base_of<From, std::remove_pointer_t<To>>::value),
                 "target type not derived from source type");
 
-  // We skip the assert and hence the dynamic_cast if RTTI is disabled.
-#if !defined(__GNUC__) || defined(__GXX_RTTI)
+// We skip the assert and hence the dynamic_cast if RTTI is disabled.
+#if ABSL_INTERNAL_HAS_RTTI
   // Uses RTTI in dbg and fastbuild. asserts are disabled in opt builds.
   assert(f == nullptr || dynamic_cast<To>(f) != nullptr);
 #endif  // !defined(__GNUC__) || defined(__GXX_RTTI)
@@ -88,7 +90,7 @@ inline To down_cast(From& f) {
                 "target type not derived from source type");
 
   // We skip the assert and hence the dynamic_cast if RTTI is disabled.
-#if !defined(__GNUC__) || defined(__GXX_RTTI)
+#if ABSL_INTERNAL_HAS_RTTI
   // RTTI: debug mode only
   assert(dynamic_cast<std::remove_reference_t<To>*>(&f) != nullptr);
 #endif  // !defined(__GNUC__) || defined(__GXX_RTTI)
@@ -289,15 +291,15 @@ inline bool tight_enum_test_cast(int e_val, Enum* e_var) {
 template <typename Enum>
 inline Enum loose_enum_cast(int e_val) {
   if (!loose_enum_test<Enum>(e_val)) {
-    S2_LOG(DFATAL) << "enum_cast error for value " << e_val;
+    S2_LOG(ERROR) << "enum_cast error for value " << e_val;
   }
   return static_cast<Enum>(e_val);
 }
 
 template <typename Enum>
 inline Enum tight_enum_cast(int e_val) {
   if (!tight_enum_test<Enum>(e_val)) {
-    S2_LOG(DFATAL) << "enum_cast error for value " << e_val;
+    S2_LOG(ERROR) << "enum_cast error for value " << e_val;
   }
   return static_cast<Enum>(e_val);
 }

src/s2/base/commandlineflags.h

@@ -18,74 +18,24 @@
 
 #include <string>
 
+#include "absl/flags/flag.h"
+
 #include "s2/base/commandlineflags_declare.h"
 #include "s2/base/integral_types.h"
-#include "absl/strings/string_view.h"
-
-#ifdef S2_USE_GFLAGS
-
-#include <gflags/gflags.h>
-
-// If the GFlags library is available, map the local macro names to
-// GFlags macros.
-#define S2_DEFINE_bool  DEFINE_bool
-#define S2_DEFINE_double  DEFINE_double
-#define S2_DEFINE_int32  DEFINE_int32
-#define S2_DEFINE_int64  DEFINE_int64
-#define S2_DEFINE_string  DEFINE_string
-
-// gflags has its own int32 definitions.
-namespace absl {
-inline int32 GetFlag(google::int32 flag) { return flag; }
-inline int64 GetFlag(google::int64 flag) { return flag; }
-inline void SetFlag(google::int32* f, google::int32 v) { *f = v; }
-inline void SetFlag(google::int64* f, google::int64 v) { *f = v; }
-}  // namespace absl
-
-#else  // !defined(S2_USE_GFLAGS)
-
-
-// Create a set of gflags-like macros for declaring/defining flags. Use
-// a library-specific name to potential minimize clashes with GFlags.
 
 #define S2_DEFINE_bool(name, default_value, description) \
-  bool FLAGS_##name = default_value
+  ABSL_FLAG(bool, name, default_value, description)
 
 #define S2_DEFINE_double(name, default_value, description) \
-  double FLAGS_##name = default_value
+  ABSL_FLAG(double, name, default_value, description)
 
 #define S2_DEFINE_int32(name, default_value, description) \
-  int32 FLAGS_##name = default_value
+  ABSL_FLAG(int32, name, default_value, description)
 
 #define S2_DEFINE_int64(name, default_value, description) \
-  int64 FLAGS_##name = default_value
+  ABSL_FLAG(int64, name, default_value, description)
 
 #define S2_DEFINE_string(name, default_value, description) \
-  std::string FLAGS_##name = default_value
-
-namespace absl {
-inline int32 GetFlag(int32 flag) { return flag; }
-inline int64 GetFlag(int64 flag) { return flag; }
-inline void SetFlag(int32* f, int32 v) { *f = v; }
-inline void SetFlag(int64* f, int64 v) { *f = v; }
-}  // namespace absl
-
-#endif  // !defined(S2_USE_GFLAGS)
-
-// Flags are declared with v1 flags, but accessed via absl::GetFlag/SetFlag.
-// TODO(user,b/205817426): Convert everything to absl flags and remove gflags.
-namespace absl {
-
-inline bool GetFlag(bool flag) { return flag; }
-inline double GetFlag(double flag) { return flag; }
-inline std::string GetFlag(const std::string& flag) { return flag; }
-
-inline void SetFlag(bool* f, bool v) { *f = v; }
-inline void SetFlag(double* f, double v) { *f = v; }
-inline void SetFlag(std::string* f, absl::string_view v) {
-  *f = std::string(v);
-}
-
-}  // namespace absl
+  ABSL_FLAG(std::string, name, default_value, description)
 
 #endif  // S2_BASE_COMMANDLINEFLAGS_H_

src/s2/base/commandlineflags_declare.h

@@ -18,35 +18,18 @@
 
 #include <string>
 
-#include "s2/base/integral_types.h"
-
-#ifdef S2_USE_GFLAGS
-
-#include <gflags/gflags.h>
+#include "absl/flags/declare.h"
 
-#define S2_DECLARE_bool(name) DECLARE_bool(name)
-#define S2_DECLARE_double(name) DECLARE_double(name)
-#define S2_DECLARE_int32(name) DECLARE_int32(name)
-#define S2_DECLARE_int64(name) DECLARE_int64(name)
-#define S2_DECLARE_string(name) DECLARE_string(name)
-
-#else  // !defined(S2_USE_GFLAGS)
-
-#define S2_DECLARE_bool(name) \
-  extern bool FLAGS_##name
+#include "s2/base/integral_types.h"
 
-#define S2_DECLARE_double(name) \
-  extern double FLAGS_##name
+#define S2_DECLARE_bool(name) ABSL_DECLARE_FLAG(bool, name)
 
-#define S2_DECLARE_int32(name) \
-  extern int32 FLAGS_##name
+#define S2_DECLARE_double(name) ABSL_DECLARE_FLAG(double, name)
 
-#define S2_DECLARE_int64(name) \
-  extern int64 FLAGS_##name
+#define S2_DECLARE_int32(name) ABSL_DECLARE_FLAG(int32, name)
 
-#define S2_DECLARE_string(name) \
-  extern std::string FLAGS_##name
+#define S2_DECLARE_int64(name) ABSL_DECLARE_FLAG(int64, name)
 
-#endif  // !defined(S2_USE_GFLAGS)
+#define S2_DECLARE_string(name) ABSL_DECLARE_FLAG(std::string, name)
 
 #endif  // S2_BASE_COMMANDLINEFLAGS_DECLARE_H_

src/s2/base/log_severity.h

@@ -16,13 +16,6 @@
 #ifndef S2_BASE_LOG_SEVERITY_H_
 #define S2_BASE_LOG_SEVERITY_H_
 
-#ifdef S2_USE_GLOG
-
-// Including <glog/log_severity.h> directly will give errors.
-#include <glog/logging.h>
-
-#else  // !defined(S2_USE_GLOG)
-
 #include "absl/base/log_severity.h"
 
 // Stay compatible with glog.
@@ -36,6 +29,4 @@ constexpr bool DEBUG_MODE = true;
 
 }  // namespace google
 
-#endif  // !defined(S2_USE_GLOG)
-
 #endif  // S2_BASE_LOG_SEVERITY_H_