Remove old cc_rules cruft. (#6388)

This is left-over from the migration completed in #5323 (as part of
b/152883646).

Briefly, we used have much more complex self-contained rules that tried
to manage sources, dependencies, and everything in a single rule like
firebase_ios_cc_library. The migration added functions like
firebase_ios_add_library that more closely matched builtin CMake
primitives. I should have sent this PR as the final one in that
sequence.

cmake/cc_rules.cmake

@@ -151,156 +151,6 @@ function(firebase_ios_add_objc_test target host)
   endif()
 endfunction()
 
-
-# firebase_ios_cc_library(
-#   target
-#   SOURCES sources...
-#   DEPENDS libraries...
-#   [EXCLUDE_FROM_ALL]
-# )
-#
-# Defines a new library target with the given target name, sources, and
-# dependencies.
-function(firebase_ios_cc_library name)
-  set(flag DISABLE_STRICT_WARNINGS EXCLUDE_FROM_ALL HEADER_ONLY)
-  set(multi DEPENDS SOURCES)
-  cmake_parse_arguments(ccl "${flag}" "" "${multi}" ${ARGN})
-
-  if(ccl_HEADER_ONLY)
-    firebase_ios_generate_dummy_source(${name} ccl_SOURCES)
-  endif()
-
-  firebase_ios_maybe_remove_objc_sources(sources ${ccl_SOURCES})
-  add_library(${name} ${sources})
-
-  set(warnings_flag "")
-  if(ccl_DISABLE_STRICT_WARNINGS)
-    set(warnings_flag DISABLE_STRICT_WARNINGS)
-  endif()
-  firebase_ios_add_compile_options(${name} ${warnings_flag} ${sources})
-
-  target_compile_options(${name} PRIVATE ${FIREBASE_IOS_CXX_FLAGS})
-  target_link_libraries(${name} PUBLIC ${ccl_DEPENDS})
-
-  if(ccl_EXCLUDE_FROM_ALL)
-    set_property(
-      TARGET ${name}
-      PROPERTY EXCLUDE_FROM_ALL ON
-    )
-  endif()
-endfunction()
-
-# firebase_ios_cc_select(
-#   interface_library
-#   CONDITION1 implementation_library1
-#   [CONDITION2 implementation_library2 ...]
-#   [DEFAULT implementation_library_default]
-# )
-#
-# Creates an INTERFACE library named `interface_library`.
-#
-# For each pair of condition and implementation_library, evaluates the condition
-# and if true makes that library an INTERFACE link library of
-# `interface_library`.
-#
-# If supplied, uses the `DEFAULT` implementation if no other condition matches.
-#
-# If no condition matches, fails the configuration cycle with an error message
-# indicating that no suitable implementation was found.
-function(firebase_ios_cc_select library_name)
-  add_library(${library_name} INTERFACE)
-
-  list(LENGTH ARGN length)
-  if(length GREATER 0)
-    math(EXPR length "${length} - 1")
-    foreach(key RANGE 0 ${length} 2)
-      math(EXPR value "${key} + 1")
-      list(GET ARGN ${key} condition)
-      list(GET ARGN ${value} impl_library)
-
-      if((${condition} STREQUAL "DEFAULT") OR (${${condition}}))
-        message("Using ${library_name} = ${impl_library}")
-        target_link_libraries(
-          ${library_name} INTERFACE ${impl_library}
-        )
-        return()
-      endif()
-    endforeach()
-  endif()
-
-  message(FATAL_ERROR "Could not find implementation for ${library_name}")
-endfunction()
-
-# firebase_ios_cc_binary(
-#   target
-#   SOURCES sources...
-#   DEPENDS libraries...
-#   [EXCLUDE_FROM_ALL]
-# )
-#
-# Defines a new executable target with the given target name, sources, and
-# dependencies.
-function(firebase_ios_cc_binary name)
-  set(flag DISABLE_STRICT_WARNINGS EXCLUDE_FROM_ALL)
-  set(multi DEPENDS SOURCES)
-  cmake_parse_arguments(ccb "${flag}" "" "${multi}" ${ARGN})
-
-  firebase_ios_maybe_remove_objc_sources(sources ${ccb_SOURCES})
-  add_executable(${name} ${sources})
-
-  set(warnings_flag "")
-  if(ccb_DISABLE_STRICT_WARNINGS)
-    set(warnings_flag DISABLE_STRICT_WARNINGS)
-  endif()
-  firebase_ios_add_compile_options(${name} ${warnings_flag} ${sources})
-
-  target_compile_options(${name} PRIVATE ${FIREBASE_CXX_FLAGS})
-  target_include_directories(${name} PRIVATE ${FIREBASE_SOURCE_DIR})
-  target_link_libraries(${name} PRIVATE ${ccb_DEPENDS})
-
-  if(ccb_EXCLUDE_FROM_ALL)
-    set_property(
-      TARGET ${name}
-      PROPERTY EXCLUDE_FROM_ALL ON
-    )
-  endif()
-endfunction()
-
-# firebase_ios_cc_test(
-#   target
-#   SOURCES sources...
-#   DEPENDS libraries...
-# )
-#
-# Defines a new test executable target with the given target name, sources, and
-# dependencies.  Implicitly adds DEPENDS on GTest::GTest and GTest::Main.
-function(firebase_ios_cc_test name)
-  if(NOT FIREBASE_IOS_BUILD_TESTS)
-    return()
-  endif()
-
-  set(flag DISABLE_STRICT_WARNINGS)
-  set(multi DEPENDS SOURCES)
-  cmake_parse_arguments(cct "${flag}" "" "${multi}" ${ARGN})
-
-  list(APPEND cct_DEPENDS GTest::GTest GTest::Main)
-
-  firebase_ios_maybe_remove_objc_sources(sources ${cct_SOURCES})
-  add_executable(${name} ${sources})
-
-  set(warnings_flag "")
-  if(cct_DISABLE_STRICT_WARNINGS)
-    set(warnings_flag DISABLE_STRICT_WARNINGS)
-  endif()
-  firebase_ios_add_compile_options(${name} ${warnings_flag} ${sources})
-
-  add_test(${name} ${name})
-
-  target_compile_options(${name} PRIVATE ${FIREBASE_CXX_FLAGS})
-  target_include_directories(${name} PRIVATE ${FIREBASE_SOURCE_DIR})
-  target_link_libraries(${name} PRIVATE ${cct_DEPENDS})
-endfunction()
-
 # firebase_ios_add_fuzz_test(
 #   target
 #   DICTIONARY dict_file
@@ -348,77 +198,6 @@ function(firebase_ios_add_fuzz_test target)
   endif()
 endfunction()
 
-# maybe_remove_objc_sources(output_var sources...)
-#
-# Removes Objective-C/C++ sources from the given sources if not on an Apple
-# platform. Stores the resulting list in the variable named by `output_var`.
-function(firebase_ios_maybe_remove_objc_sources output_var)
-  unset(sources)
-  foreach(source ${ARGN})
-    get_filename_component(ext ${source} EXT)
-    if(NOT APPLE AND ((ext STREQUAL ".m") OR (ext STREQUAL ".mm")))
-      continue()
-    endif()
-    list(APPEND sources ${source})
-  endforeach()
-  set(${output_var} ${sources} PARENT_SCOPE)
-endfunction()
-
-# firebase_ios_add_compile_options(target [DISABLE_STRICT_WARNINGS] sources...)
-#
-# Adds FIREBASE_IOS_CXX_FLAGS or FIREBASE_IOS_CXX_FLAGS_STRICT to the compile
-# options of the given target depending on whether or not
-# DISABLE_STRICT_WARNINGS was passed.
-#
-# If any of the sources have filenames that indicate they are Objective-C adds
-# Either FIREBASE_IOS_OBJC_FLAGS or FIREBASE_IOS_OBJC_FLAGS_STRICT depending on
-# whether or not DISABLE_STRICT_WARNINGS was passed.
-function(firebase_ios_add_compile_options target)
-  set(flag DISABLE_STRICT_WARNINGS)
-  cmake_parse_arguments(aco "${flag}" "" "" ${ARGN})
-
-  # Only set Objective-C flags if there's at least once source file to which
-  # that applies.
-  set(has_objc OFF)
-
-  # Default to applying the strict warnings to all targets, but targets can
-  # opt out.
-  set(suffix _STRICT)
-  if(aco_DISABLE_STRICT_WARNINGS)
-    set(suffix "")
-  endif()
-
-  foreach(source ${ARGN})
-    get_filename_component(ext ${source} EXT)
-    if((ext STREQUAL ".m") OR (ext STREQUAL ".mm"))
-      set(has_objc ON)
-    endif()
-  endforeach()
-
-  target_compile_options(
-    ${target}
-    PRIVATE
-    ${FIREBASE_IOS_CXX_FLAGS${suffix}}
-  )
-
-  if(has_objc)
-    target_compile_options(
-      ${target}
-      PRIVATE
-      ${FIREBASE_IOS_OBJC_FLAGS${suffix}}
-    )
-  endif()
-
-  target_include_directories(
-    ${target}
-    PRIVATE
-    # Put the binary dir first so that the generated config.h trumps any one
-    # generated statically by a Cocoapods-based build in the same source tree.
-    ${FIREBASE_BINARY_DIR}
-    ${FIREBASE_SOURCE_DIR}
-  )
-endfunction()
-
 # firebase_ios_add_alias(alias_target actual_target)
 #
 # Adds a library alias target `alias_target` if it does not already exist,
@@ -431,60 +210,6 @@ function(firebase_ios_add_alias ALIAS_TARGET ACTUAL_TARGET)
   endif()
 endfunction()
 
-function(firebase_ios_objc_test target)
-  if(NOT APPLE OR NOT FIREBASE_IOS_BUILD_TESTS)
-    return()
-  endif()
-
-  set(flag DISABLE_STRICT_WARNINGS EXCLUDE_FROM_ALL)
-  set(single HOST VERSION WORKING_DIRECTORY)
-  set(multi DEPENDS DEFINES HEADERS INCLUDES SOURCES)
-  cmake_parse_arguments(ot "${flag}" "${single}" "${multi}" ${ARGN})
-
-  xctest_add_bundle(
-    ${target}
-    ${ot_HOST}
-    ${ot_SOURCES}
-  )
-
-  set(warnings_flag "")
-  if(ot_DISABLE_STRICT_WARNINGS)
-    set(warnings_flag DISABLE_STRICT_WARNINGS)
-  endif()
-  firebase_ios_add_compile_options(${target} ${warnings_flag} ${ot_SOURCES})
-
-  target_compile_options(${target} PRIVATE ${FIREBASE_CXX_FLAGS})
-  target_link_libraries(${target} PRIVATE ${ot_DEPENDS})
-
-  xctest_add_test(
-    ${target}
-    ${target}
-  )
-
-  if(ot_WORKING_DIRECTORY)
-    set_property(
-      TEST ${target} PROPERTY
-      WORKING_DIRECTORY ${ot_WORKING_DIRECTORY}
-    )
-  endif()
-
-  if(WITH_ASAN)
-    set_property(
-      TEST ${target} APPEND PROPERTY
-      ENVIRONMENT
-      DYLD_INSERT_LIBRARIES=${CLANG_ASAN_DYLIB}
-    )
-  endif()
-
-  if(WITH_TSAN)
-    set_property(
-      TEST ${target} APPEND PROPERTY
-      ENVIRONMENT
-      DYLD_INSERT_LIBRARIES=${CLANG_TSAN_DYLIB}
-    )
-  endif()
-endfunction()
-
 # firebase_ios_generate_dummy_source(target, sources_list)
 #
 # Generates a dummy source file containing a single symbol, suitable for use as