[CMake] Implement absl_cc_library as Bazel's cc_library

cc_library

CMake/AbseilHelpers.cmake

@@ -62,7 +62,114 @@ function(absl_library)
   endif()
 endfunction()
 
+#
+# CMake function to imitate Bazel's cc_library rule.
+#
+# Parameters:
+# NAME: name of target (see Note)
+# HDRS: List of public header files for the library
+# SRCS: List of source files for the library
+# DEPS: List of other libraries to be linked in to the binary targets
+# COPTS: List of private compile options
+# DEFINES: List of public defines
+# LINKOPTS: List of link options
+# VISIBILITY_PUBLIC: Add this so that this library will be exported under absl:: (see Note).
+# TESTONLY: When added, this target will only be built if user passes -DBUILD_TESTING=ON to CMake.
+#
+# Note:
+#
+# By default, absl_cc_library will always create a library named absl_${NAME},
+# which means other targets can only depend this library as absl_${NAME}, not ${NAME}.
+# This is to reduce namespace pollution.
+#
+# absl_cc_library(
+#   NAME
+#     awesome_lib
+#   HDRS
+#     "a.h"
+#   SRCS
+#     "a.cc"
+# )
+# absl_cc_library(
+#   NAME
+#     fantastic_lib
+#   SRCS
+#     "b.cc"
+#   DEPS
+#     absl_awesome_lib # not "awesome_lib"!
+# )
+#
+# If VISIBILITY_PUBLIC is set, absl_cc_library will also create an alias absl::${NAME}
+# for public use.
+#
+# absl_cc_library(
+#   NAME
+#     main_lib
+#   ...
+#   VISIBILITY_PUBLIC
+# )
+#
+# User can then use the library as absl::main_lib (although absl_main_lib is defined too).
+#
+# TODO: Implement "ALWAYSLINK"
 
+function(absl_cc_library)
+  cmake_parse_arguments(ABSL_CC_LIB
+    "DISABLE_INSTALL;VISIBILITY_PUBLIC;TESTONLY"
+    "NAME"
+    "HDRS;SRCS;COPTS;DEFINES;LINKOPTS;DEPS"
+    ${ARGN}
+  )
+
+  if (NOT ABSL_CC_LIB_TESTONLY OR BUILD_TESTING)
+    set(_NAME "absl_${ABSL_CC_LIB_NAME}")
+    string(TOUPPER ${_NAME} _UPPER_NAME)
+
+    # Check if this is a header-only library
+    if (ABSL_CC_LIB_SRCS)
+      set(_SRCS ${ABSL_CC_LIB_SRCS})
+      list(FILTER _SRCS INCLUDE REGEX "\.cc$")
+      list(LENGTH _SRCS ABSL_CC_LIB_SRCS_LEN)
+    else()
+      set(ABSL_CC_LIB_SRCS_LEN 0)
+    endif()
+
+    if(ABSL_CC_LIB_SRCS_LEN)
+      add_library(${_NAME} STATIC ${ABSL_CC_LIB_SRCS} ${ABSL_CC_LIB_HDRS})
+    else()
+      set(__dummy_header_only_lib_file "${CMAKE_CURRENT_BINARY_DIR}/${_NAME}_header_only_dummy.cc")
+
+      if(NOT EXISTS ${__dummy_header_only_lib_file})
+        file(WRITE ${__dummy_header_only_lib_file}
+          "/* generated file for header-only cmake target */
+
+          namespace absl {
+            // single meaningless symbol
+            void ${_NAME}__header_fakesym() {}
+          }  // namespace absl")
+      endif()
+
+      add_library(${_NAME} ${__dummy_header_only_lib_file} ${ABSL_CC_LIB_HDRS})
+    endif()
+
+    target_compile_options(${_NAME} PRIVATE ${ABSL_COMPILE_CXXFLAGS} ${ABSL_CC_LIB_COPTS})
+    target_link_libraries(${_NAME}
+      PUBLIC ${ABSL_CC_LIB_DEPS}
+      PRIVATE ${ABSL_CC_LIB_LINKOPTS}
+    )
+    target_compile_definitions(${_NAME} PUBLIC ${ABSL_CC_LIB_DEFINES})
+
+    target_include_directories(${_NAME}
+      PUBLIC ${ABSL_COMMON_INCLUDE_DIRS}
+    )
+    # Add all Abseil targets to a a folder in the IDE for organization.
+    set_property(TARGET ${_NAME} PROPERTY FOLDER ${ABSL_IDE_FOLDER})
+
+    if(ABSL_CC_LIB_VISIBILITY_PUBLIC)
+      add_library(absl::${ABSL_CC_LIB_NAME} ALIAS ${_NAME})
+    endif()
+  endif()
+endfunction()
 
 #
 # header only virtual target creation

absl/base/CMakeLists.txt

@@ -99,34 +99,27 @@ absl_library(
     throw_delegate
 )
 
-if(BUILD_TESTING)
+
 # exception-safety testing library
-  set(EXCEPTION_SAFETY_TESTING_SRC
+absl_cc_library(
+  NAME
+    exception_safety_testing
+  HDRS
     "internal/exception_safety_testing.h"
+  SRCS
     "internal/exception_safety_testing.cc"
-  )
+  COPTS
-  set(EXCEPTION_SAFETY_TESTING_PUBLIC_LIBRARIES
+    ${ABSL_EXCEPTIONS_FLAG}
-    ${ABSL_TEST_COMMON_LIBRARIES}
+  DEPS
     absl::base
     absl::memory
     absl::meta
     absl::strings
     absl::optional
     gtest
+  TESTONLY
 )
 
-absl_library(
-  TARGET
-    absl_base_internal_exception_safety_testing
-  SOURCES
-    ${EXCEPTION_SAFETY_TESTING_SRC}
-  PUBLIC_LIBRARIES
-    ${EXCEPTION_SAFETY_TESTING_PUBLIC_LIBRARIES}
-  PRIVATE_COMPILE_FLAGS
-    ${ABSL_EXCEPTIONS_FLAG}
-)
-endif()
-
 
 # dynamic_annotations library
 set(DYNAMIC_ANNOTATIONS_SRC "dynamic_annotations.cc")
@@ -368,7 +361,7 @@ absl_test(
 set(EXCEPTION_SAFETY_TESTING_TEST_SRC "exception_safety_testing_test.cc")
 set(EXCEPTION_SAFETY_TESTING_TEST_PUBLIC_LIBRARIES
   absl::base
-  absl_base_internal_exception_safety_testing
+  absl_exception_safety_testing
   absl::memory
   absl::meta
   absl::strings

absl/strings/CMakeLists.txt

@@ -14,8 +14,10 @@
 # limitations under the License.
 #
 
-
+absl_cc_library(
-list(APPEND STRINGS_PUBLIC_HEADERS
+  NAME
+    strings
+  HDRS
     "ascii.h"
     "charconv.h"
     "escaping.h"
@@ -28,35 +30,26 @@ list(APPEND STRINGS_PUBLIC_HEADERS
     "str_replace.h"
     "str_split.h"
     "substitute.h"
-)
+  SRCS
-
+    "ascii.cc"
-
+    "charconv.cc"
-list(APPEND STRINGS_INTERNAL_HEADERS
+    "escaping.cc"
+    "internal/bits.h"
     "internal/char_map.h"
+    "internal/charconv_bigint.cc"
     "internal/charconv_bigint.h"
+    "internal/charconv_parse.cc"
     "internal/charconv_parse.h"
+    "internal/memutil.cc"
     "internal/memutil.h"
+    "internal/ostringstream.cc"
     "internal/ostringstream.h"
     "internal/resize_uninitialized.h"
     "internal/stl_type_traits.h"
     "internal/str_join_internal.h"
     "internal/str_split_internal.h"
-  "internal/utf8.h"
-)
-
-
-
-# add string library
-list(APPEND STRINGS_SRC
-  "ascii.cc"
-  "charconv.cc"
-  "escaping.cc"
-  "internal/charconv_bigint.cc"
-  "internal/charconv_parse.cc"
-  "internal/memutil.cc"
-  "internal/memutil.h"
     "internal/utf8.cc"
-  "internal/ostringstream.cc"
+    "internal/utf8.h"
     "match.cc"
     "numbers.cc"
     "str_cat.cc"
@@ -64,37 +57,28 @@ list(APPEND STRINGS_SRC
     "str_split.cc"
     "string_view.cc"
     "substitute.cc"
-  ${STRINGS_PUBLIC_HEADERS}
+  DEPS
-  ${STRINGS_INTERNAL_HEADERS}
+    absl::base
-)
+    absl_throw_delegate
-set(STRINGS_PUBLIC_LIBRARIES absl::base absl_throw_delegate)
+  VISIBILITY_PUBLIC
-
-absl_library(
-  TARGET
-    absl_strings
-  SOURCES
-    ${STRINGS_SRC}
-  PUBLIC_LIBRARIES
-    ${STRINGS_PUBLIC_LIBRARIES}
-  EXPORT_NAME
-    strings
 )
 
 # add str_format library
-absl_header_library(
+absl_cc_library(
-  TARGET
+  NAME
-    absl_str_format
-  PUBLIC_LIBRARIES
-    str_format_internal
-  EXPORT_NAME
     str_format
+  HDRS
+    "str_format.h"
+  DEPS
+    absl_str_format_internal
+  VISIBILITY_PUBLIC
 )
 
 # str_format_internal
-absl_library(
+absl_cc_library(
-  TARGET
+  NAME
     str_format_internal
-  SOURCES
+  SRCS
     "internal/str_format/arg.cc"
     "internal/str_format/bind.cc"
     "internal/str_format/extension.cc"
@@ -108,7 +92,7 @@ absl_library(
     "internal/str_format/float_conversion.h"
     "internal/str_format/output.h"
     "internal/str_format/parser.h"
-  PUBLIC_LIBRARIES
+  DEPS
     str_format_extension_internal
     absl::strings
     absl::base
@@ -415,7 +399,7 @@ absl_test(
   SOURCES
     "internal/str_format/bind_test.cc"
   PUBLIC_LIBRARIES
-    str_format_internal
+    absl_str_format_internal
 )
 
 # test str_format_checker_test
@@ -435,7 +419,7 @@ absl_test(
   SOURCES
     "internal/str_format/convert_test.cc"
   PUBLIC_LIBRARIES
-    str_format_internal
+    absl_str_format_internal
     absl::numeric
 )
 
@@ -456,7 +440,7 @@ absl_test(
   SOURCES
     "internal/str_format/parser_test.cc"
   PUBLIC_LIBRARIES
-    str_format_internal
+    absl_str_format_internal
     absl::base
 )