build: Add build target to generate coverage report

This adds a 'make coverage' option to conveniently summarize test
coverage. If lcov is installed, it will also automatically generate
the HTML summary.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 333 insertions, 0 deletions

diff --git a/cmake/utils/PrintCoverage.cmake b/cmake/utils/PrintCoverage.cmake
new file mode 100644
index 00000000..4b75fa09
--- /dev/null
+++ b/cmake/utils/PrintCoverage.cmake
@@ -0,0 +1,333 @@
+# Script to parse and display coverage results from CTest
+#
+# This script is invoked by the 'make coverage' target and parses the CTest
+# Coverage.xml file to generate a formatted coverage report grouped by component.
+#
+# This script is run with cmake -P, so CMAKE_SOURCE_DIR won't be set correctly.
+# Use PROJECT_SOURCE_DIR and PROJECT_BINARY_DIR passed as -D arguments.
+
+if(NOT DEFINED PROJECT_SOURCE_DIR)
+  message(FATAL_ERROR "PROJECT_SOURCE_DIR must be defined")
+endif()
+if(NOT DEFINED PROJECT_BINARY_DIR)
+  message(FATAL_ERROR "PROJECT_BINARY_DIR must be defined")
+endif()
+
+# Include coverage parsing functions
+include(${CMAKE_CURRENT_LIST_DIR}/ParseCoverage.cmake)
+
+# Create padding strings (CMake 2.8 compatible)
+function(make_padding LENGTH OUTPUT_VAR)
+  set(RESULT "")
+  if(LENGTH GREATER 0)
+    foreach(i RANGE 1 ${LENGTH})
+      set(RESULT "${RESULT} ")
+    endforeach()
+  endif()
+  set(${OUTPUT_VAR} "${RESULT}" PARENT_SCOPE)
+endfunction()
+
+# Format a number with padding for right alignment
+function(format_number VALUE WIDTH OUTPUT_VAR)
+  string(LENGTH "${VALUE}" VALUE_LEN)
+  math(EXPR PAD_LEN "${WIDTH} - ${VALUE_LEN}")
+  make_padding(${PAD_LEN} PADDING)
+  set(${OUTPUT_VAR} "${PADDING}${VALUE}" PARENT_SCOPE)
+endfunction()
+
+# Format a complete coverage row with consistent alignment
+function(format_coverage_row LABEL TESTED TESTED_FC UNTESTED UNTESTED_FC TOTAL PERCENT OUTPUT_VAR)
+  string(LENGTH "${LABEL}" LABEL_LEN)
+  math(EXPR LABEL_PAD "28 - ${LABEL_LEN}")
+  make_padding(${LABEL_PAD} LP)
+
+  format_number(${TESTED} 6 TS)
+  format_number(${TESTED_FC} 3 TFC)
+  format_number(${UNTESTED} 8 US)
+  format_number(${UNTESTED_FC} 3 UFC)
+  format_number(${TOTAL} 5 TT)
+  format_number(${PERCENT} 3 PC)
+  set(${OUTPUT_VAR} "    ${LABEL}${LP}${TS}[${TFC}] ${US}[${UFC}]   ${TT}    ${PC}%" PARENT_SCOPE)
+endfunction()
+
+# Format the header row to align with data columns
+function(format_coverage_header OUTPUT_VAR)
+  set(HEADER "    Component                        Tested      Untested   Total       %")
+  set(${OUTPUT_VAR} "${HEADER}" PARENT_SCOPE)
+endfunction()
+
+# Calculate metrics from entry list (pipe-delimited: path|name|tested|untested|total|percent)
+function(calculate_metrics ENTRIES OUT_TESTED OUT_UNTESTED OUT_TESTED_FC OUT_UNTESTED_FC)
+  set(TESTED 0)
+  set(UNTESTED 0)
+  set(TESTED_FC 0)
+  set(UNTESTED_FC 0)
+
+  foreach(ENTRY ${ENTRIES})
+    string(REPLACE "|" ";" PARTS "${ENTRY}")
+    list(GET PARTS 2 ENTRY_TESTED)
+    list(GET PARTS 3 ENTRY_UNTESTED)
+
+    math(EXPR TESTED "${TESTED} + ${ENTRY_TESTED}")
+    math(EXPR UNTESTED "${UNTESTED} + ${ENTRY_UNTESTED}")
+
+    if(ENTRY_TESTED EQUAL 0)
+      math(EXPR UNTESTED_FC "${UNTESTED_FC} + 1")
+    else()
+      math(EXPR TESTED_FC "${TESTED_FC} + 1")
+    endif()
+  endforeach()
+
+  set(${OUT_TESTED} "${TESTED}" PARENT_SCOPE)
+  set(${OUT_UNTESTED} "${UNTESTED}" PARENT_SCOPE)
+  set(${OUT_TESTED_FC} "${TESTED_FC}" PARENT_SCOPE)
+  set(${OUT_UNTESTED_FC} "${UNTESTED_FC}" PARENT_SCOPE)
+endfunction()
+
+# Discover components and sub-components from source tree
+function(discover_components PROJECT_SOURCE_DIR OUT_COMPONENTS OUT_COMP_SUBCOMPS)
+  file(GLOB COMPONENT_DIRS "${PROJECT_SOURCE_DIR}/src/*")
+  set(COMPONENTS "")
+  set(SKIP_DIRS "include;doc;tests")
+
+  foreach(DIR ${COMPONENT_DIRS})
+    if(IS_DIRECTORY ${DIR})
+      get_filename_component(COMP_NAME ${DIR} NAME)
+      list(FIND SKIP_DIRS ${COMP_NAME} SKIP_IDX)
+      if(SKIP_IDX EQUAL -1)
+        list(APPEND COMPONENTS ${COMP_NAME})
+
+        file(GLOB SUBCOMP_DIRS "${DIR}/*")
+        set(COMP_${COMP_NAME}_SUBCOMPS "")
+        foreach(SUBDIR ${SUBCOMP_DIRS})
+          if(IS_DIRECTORY ${SUBDIR})
+            get_filename_component(SUBCOMP_NAME ${SUBDIR} NAME)
+            list(FIND SKIP_DIRS ${SUBCOMP_NAME} SKIP_IDX2)
+            if(SKIP_IDX2 EQUAL -1)
+              list(APPEND COMP_${COMP_NAME}_SUBCOMPS ${SUBCOMP_NAME})
+              set(COMP_${COMP_NAME}_${SUBCOMP_NAME} "")
+            endif()
+          endif()
+        endforeach()
+      endif()
+    endif()
+  endforeach()
+
+  set(${OUT_COMPONENTS} "${COMPONENTS}" PARENT_SCOPE)
+  foreach(COMP ${COMPONENTS})
+    set(COMP_${COMP}_SUBCOMPS "${COMP_${COMP}_SUBCOMPS}" PARENT_SCOPE)
+  endforeach()
+endfunction()
+
+# Print a coverage line
+function(print_coverage_line LABEL TESTED TESTED_FC UNTESTED UNTESTED_FC TOTAL PERCENT)
+  format_coverage_row("${LABEL}" ${TESTED} ${TESTED_FC} ${UNTESTED} ${UNTESTED_FC} ${TOTAL} ${PERCENT} ROW)
+  execute_process(COMMAND ${CMAKE_COMMAND} -E echo "${ROW}")
+endfunction()
+
+# Locate the coverage file
+if(NOT EXISTS "${CMAKE_BINARY_DIR}/Testing/TAG")
+  message(WARNING "Testing/TAG file not found. Coverage may not have run successfully.")
+  return()
+endif()
+
+file(STRINGS "${CMAKE_BINARY_DIR}/Testing/TAG" TAG_CONTENTS LIMIT_COUNT 1)
+string(STRIP "${TAG_CONTENTS}" TEST_DIR)
+set(COVERAGE_FILE "${CMAKE_BINARY_DIR}/Testing/${TEST_DIR}/Coverage.xml")
+
+if(NOT EXISTS "${COVERAGE_FILE}")
+  message(WARNING "Coverage file not found: ${COVERAGE_FILE}")
+  execute_process(COMMAND ${CMAKE_COMMAND} -E echo "Note: Coverage results should be in Testing/${TEST_DIR}/")
+  return()
+endif()
+
+# Parse the coverage XML file
+parse_coverage_xml("${COVERAGE_FILE}" "${PROJECT_SOURCE_DIR}")
+
+if(NOT LOC_TESTED OR NOT LOC_UNTESTED)
+  message(WARNING "Could not parse coverage metrics")
+  return()
+endif()
+
+math(EXPR TOTAL_LOC "${LOC_TESTED} + ${LOC_UNTESTED}")
+if(NOT TOTAL_LOC GREATER 0)
+  message(WARNING "No coverage data found")
+  return()
+endif()
+
+math(EXPR COVERAGE_PERCENT "(${LOC_TESTED} * 100) / ${TOTAL_LOC}")
+
+# Discover and group files by component
+if(NOT FILE_COVERAGE_LIST)
+  execute_process(COMMAND ${CMAKE_COMMAND} -E echo "No coverage data for source files (excluding tests)")
+  return()
+endif()
+
+# Discover components from source tree (only src/ directory)
+discover_components("${PROJECT_SOURCE_DIR}" COMPONENTS COMP_SUBCOMPS)
+
+# Find all source files and identify completely untested ones
+file(GLOB_RECURSE ALL_SOURCE_FILES "${PROJECT_SOURCE_DIR}/src/*.c")
+set(UNCOVERED_FILES "")
+foreach(SRC_FILE ${ALL_SOURCE_FILES})
+  if(SRC_FILE MATCHES "test" OR SRC_FILE MATCHES "/tests/")
+    continue()
+  endif()
+
+  list(FIND COVERED_FILES "${SRC_FILE}" FILE_IDX)
+  if(FILE_IDX EQUAL -1)
+    file(STRINGS "${SRC_FILE}" FILE_LINES)
+    list(LENGTH FILE_LINES LINE_COUNT)
+    if(LINE_COUNT GREATER 0)
+      get_filename_component(FILE_NAME "${SRC_FILE}" NAME)
+      list(APPEND UNCOVERED_FILES "${SRC_FILE}|${FILE_NAME}|0|${LINE_COUNT}|${LINE_COUNT}|0")
+    endif()
+  endif()
+endforeach()
+
+# Combine covered and uncovered files
+set(ALL_FILES ${FILE_COVERAGE_LIST})
+if(UNCOVERED_FILES)
+  list(APPEND ALL_FILES ${UNCOVERED_FILES})
+endif()
+
+# Group files into components and sub-components
+foreach(ENTRY ${ALL_FILES})
+  string(REPLACE "|" ";" ENTRY_PARTS "${ENTRY}")
+  list(GET ENTRY_PARTS 0 F_PATH)
+
+  # Normalize path and extract relative path from src/
+  # Remove leading ./ if present, then ensure path starts with src/
+  string(REGEX REPLACE "^\\./" "" REL_PATH "${F_PATH}")
+  string(REGEX REPLACE "^.*/src/" "src/" REL_PATH "${REL_PATH}")
+
+  # Tokenize on /: ["src", "component", "subcomponent", "file.c"]
+  string(REPLACE "/" ";" PATH_TOKENS "${REL_PATH}")
+  list(LENGTH PATH_TOKENS TOKEN_COUNT)
+
+  if(TOKEN_COUNT EQUAL 3)
+    # src/component/file.c - add to component main
+    list(GET PATH_TOKENS 1 FILE_COMP)
+    list(FIND COMPONENTS ${FILE_COMP} COMP_IDX)
+    if(COMP_IDX GREATER -1)
+      list(APPEND COMP_${FILE_COMP} "${ENTRY}")
+      list(APPEND COMP_${FILE_COMP}_main "${ENTRY}")
+    endif()
+  elseif(TOKEN_COUNT GREATER 3)
+    # src/component/subdir/.../file.c - check if subdir is a known subcomponent
+    list(GET PATH_TOKENS 1 FILE_COMP)
+    list(GET PATH_TOKENS 2 FILE_SUBCOMP)
+
+    list(FIND COMPONENTS ${FILE_COMP} COMP_IDX)
+    if(COMP_IDX GREATER -1)
+      list(APPEND COMP_${FILE_COMP} "${ENTRY}")
+
+      # Check if subdir is a recognized subcomponent
+      list(FIND COMP_${FILE_COMP}_SUBCOMPS ${FILE_SUBCOMP} SUBCOMP_IDX)
+      if(SUBCOMP_IDX GREATER -1)
+        list(APPEND COMP_${FILE_COMP}_${FILE_SUBCOMP} "${ENTRY}")
+      else()
+        # Subdir not recognized, treat as main
+        list(APPEND COMP_${FILE_COMP}_main "${ENTRY}")
+      endif()
+    endif()
+  endif()
+endforeach()
+
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "")
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "=============================================================================")
+format_coverage_header(HEADER)
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "${HEADER}")
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "=============================================================================")
+
+# Process and display each component
+foreach(COMP_NAME ${COMPONENTS})
+  set(COMP_LIST ${COMP_${COMP_NAME}})
+
+  if(NOT COMP_LIST)
+    continue()
+  endif()
+
+  calculate_metrics("${COMP_LIST}" COMP_TESTED COMP_UNTESTED COMP_TESTED_FILE_COUNT COMP_UNTESTED_FILE_COUNT)
+  math(EXPR COMP_TOTAL "${COMP_TESTED} + ${COMP_UNTESTED}")
+  if(COMP_TOTAL GREATER 0)
+    math(EXPR COMP_PERCENT "(${COMP_TESTED} * 100) / ${COMP_TOTAL}")
+  else()
+    set(COMP_PERCENT 0)
+  endif()
+
+  print_coverage_line("${COMP_NAME}" ${COMP_TESTED} ${COMP_TESTED_FILE_COUNT} ${COMP_UNTESTED} ${COMP_UNTESTED_FILE_COUNT} ${COMP_TOTAL} ${COMP_PERCENT})
+
+  # Display "main" sub-component first if it has files
+  set(MAIN_LIST ${COMP_${COMP_NAME}_main})
+  if(MAIN_LIST)
+    calculate_metrics("${MAIN_LIST}" MAIN_TESTED MAIN_UNTESTED MAIN_TESTED_FILE_COUNT MAIN_UNTESTED_FILE_COUNT)
+    math(EXPR MAIN_TOTAL "${MAIN_TESTED} + ${MAIN_UNTESTED}")
+    if(MAIN_TOTAL GREATER 0)
+      math(EXPR MAIN_PERCENT "(${MAIN_TESTED} * 100) / ${MAIN_TOTAL}")
+    else()
+      set(MAIN_PERCENT 0)
+    endif()
+
+    print_coverage_line("  ." ${MAIN_TESTED} ${MAIN_TESTED_FILE_COUNT} ${MAIN_UNTESTED} ${MAIN_UNTESTED_FILE_COUNT} ${MAIN_TOTAL} ${MAIN_PERCENT})
+  endif()
+
+  # Display sub-components
+  foreach(SUBCOMP ${COMP_${COMP_NAME}_SUBCOMPS})
+    set(SUBCOMP_LIST ${COMP_${COMP_NAME}_${SUBCOMP}})
+    if(NOT SUBCOMP_LIST)
+      continue()
+    endif()
+
+    calculate_metrics("${SUBCOMP_LIST}" SUBCOMP_TESTED SUBCOMP_UNTESTED SUBCOMP_TESTED_FILE_COUNT SUBCOMP_UNTESTED_FILE_COUNT)
+    math(EXPR SUBCOMP_TOTAL "${SUBCOMP_TESTED} + ${SUBCOMP_UNTESTED}")
+    if(SUBCOMP_TOTAL GREATER 0)
+      math(EXPR SUBCOMP_PERCENT "(${SUBCOMP_TESTED} * 100) / ${SUBCOMP_TOTAL}")
+    else()
+      set(SUBCOMP_PERCENT 0)
+    endif()
+
+    print_coverage_line("  ${SUBCOMP}" ${SUBCOMP_TESTED} ${SUBCOMP_TESTED_FILE_COUNT} ${SUBCOMP_UNTESTED} ${SUBCOMP_UNTESTED_FILE_COUNT} ${SUBCOMP_TOTAL} ${SUBCOMP_PERCENT})
+  endforeach()
+
+  execute_process(COMMAND ${CMAKE_COMMAND} -E echo "")
+endforeach()
+
+# Calculate overall coverage
+set(TOTAL_TESTED ${LOC_TESTED})
+set(TOTAL_UNTESTED ${LOC_UNTESTED})
+
+# Count file coverage for totals
+set(TOTAL_TESTED_FILE_COUNT 0)
+set(TOTAL_UNTESTED_FILE_COUNT 0)
+
+foreach(ENTRY ${FILE_COVERAGE_LIST})
+  string(REPLACE "|" ";" PARTS "${ENTRY}")
+  list(GET PARTS 2 ENTRY_TESTED)
+  if(ENTRY_TESTED EQUAL 0)
+    math(EXPR TOTAL_UNTESTED_FILE_COUNT "${TOTAL_UNTESTED_FILE_COUNT} + 1")
+  else()
+    math(EXPR TOTAL_TESTED_FILE_COUNT "${TOTAL_TESTED_FILE_COUNT} + 1")
+  endif()
+endforeach()
+
+# Add untested file counts
+foreach(ENTRY ${UNCOVERED_FILES})
+  string(REPLACE "|" ";" PARTS "${ENTRY}")
+  list(GET PARTS 3 ENTRY_UNTESTED)
+  math(EXPR TOTAL_UNTESTED "${TOTAL_UNTESTED} + ${ENTRY_UNTESTED}")
+  math(EXPR TOTAL_UNTESTED_FILE_COUNT "${TOTAL_UNTESTED_FILE_COUNT} + 1")
+endforeach()
+
+math(EXPR TOTAL_ALL_LOC "${TOTAL_TESTED} + ${TOTAL_UNTESTED}")
+if(TOTAL_ALL_LOC GREATER 0)
+  math(EXPR OVERALL_COVERAGE_PERCENT "(${TOTAL_TESTED} * 100) / ${TOTAL_ALL_LOC}")
+else()
+  set(OVERALL_COVERAGE_PERCENT 0)
+endif()
+
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "=============================================================================")
+print_coverage_line("Total" ${TOTAL_TESTED} ${TOTAL_TESTED_FILE_COUNT} ${TOTAL_UNTESTED} ${TOTAL_UNTESTED_FILE_COUNT} ${TOTAL_ALL_LOC} ${OVERALL_COVERAGE_PERCENT})
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "=============================================================================")
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "")
+execute_process(COMMAND ${CMAKE_COMMAND} -E echo "Detailed XML report: ${COVERAGE_FILE}")