cmake: build tool_hugehelp (ENABLE_MANUAL)

Rather than always outputting an empty manual page for the '-M' option,
generate a full manual page as done by autotools. For simplicity in
CMake, always generate the gzipped page as it will not be used anyway
when zlib is not available.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>

3 files changed, 65 insertions, 7 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0f8e50331..13bd39e7b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -174,6 +174,36 @@ mark_as_advanced(DISABLED_THREADSAFE)
 option(ENABLE_IPV6 "Define if you want to enable IPv6 support" OFF)
 mark_as_advanced(ENABLE_IPV6)
 
+option(ENABLE_MANUAL "to provide the built-in manual" ON)
+unset(USE_MANUAL CACHE) # TODO: cache NROFF/NROFF_MANOPT/USE_MANUAL vars?
+if(ENABLE_MANUAL)
+  find_program(NROFF NAMES gnroff nroff)
+  if(NROFF)
+    # Need a way to write to stdin, this will do
+    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/nroff-input.txt" "test")
+    # Tests for a valid nroff option to generate a manpage
+    foreach(_MANOPT "-man" "-mandoc")
+      execute_process(COMMAND "${NROFF}" ${_MANOPT}
+        OUTPUT_VARIABLE NROFF_MANOPT_OUTPUT
+        INPUT_FILE "${CMAKE_CURRENT_BINARY_DIR}/nroff-input.txt"
+        ERROR_QUIET)
+      # Save the option if it was valid
+      if(NROFF_MANOPT_OUTPUT)
+        message("Found *nroff option: -- ${_MANOPT}")
+        set(NROFF_MANOPT ${_MANOPT})
+        set(USE_MANUAL 1)
+        break()
+      endif()
+    endforeach()
+    # No need for the temporary file
+    file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/nroff-input.txt")
+    if(NOT USE_MANUAL)
+      message(WARNING "Found no *nroff option to get plaintext from man pages")
+    endif()
+  else()
+    message(WARNING "Found no *nroff program")
+  endif()
+endif()
 
 # We need ansi c-flags, especially on HP
 set(CMAKE_C_FLAGS "${CMAKE_ANSI_CFLAGS} ${CMAKE_C_FLAGS}")
diff --git a/docs/INSTALL.cmake b/docs/INSTALL.cmake
index f5d32d898..dd8c93674 100644
--- a/docs/INSTALL.cmake
+++ b/docs/INSTALL.cmake
@@ -24,7 +24,6 @@ Current flaws in the curl CMake build
    Missing features in the cmake build:
 
    - Builds libcurl without large file support
-   - It doesn't build src/tool_hugehelp.c which creates the --manual output
    - Can't select which SSL library to build with, only OpenSSL
    - Doesn't build with SCP and SFTP support (libssh2)
    - Doesn't allow different resolver backends (no c-ares build support)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index fceaf10fb..9c1fd54ab 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,11 +1,38 @@
 set(EXE_NAME curl)
 
-# First try to locate tool_hugehelp.c to see if it has already been created
-# TODO Find the file WITHOUT adding a cache entry!!! Or else the user can delete the file after the script was first run, and the script won't notice it has gone.
-find_file(HUGEHELP_C_FILE tool_hugehelp.c PATHS . NO_DEFAULT_PATH)
-if (NOT HUGEHELP_C_FILE)
-  message(STATUS "Warning: tool_hugehelp.c file was not generated before. Generating an 'empty' file...")
-  file(WRITE tool_hugehelp.c "/* built-in manual is disabled, blank function */\n#include \"tool_hugehelp.h\"\nvoid hugehelp(void) {}\n\n")
+if(USE_MANUAL)
+  find_package(Perl REQUIRED)
+  # Use the C locale to ensure that only ASCII characters appear in the
+  # embedded text. NROFF and MANOPT are set in the parent CMakeLists.txt
+  add_custom_command(
+    OUTPUT tool_hugehelp.c
+    COMMAND echo "#include \"tool_setup.h\"" > tool_hugehelp.c
+    COMMAND echo "#ifndef HAVE_LIBZ" >> tool_hugehelp.c
+    COMMAND env LC_ALL=C "${NROFF}" ${NROFF_MANOPT}
+            "${CURL_SOURCE_DIR}/docs/curl.1" |
+            "${PERL}" "${CMAKE_CURRENT_SOURCE_DIR}/mkhelp.pl"
+            "${CURL_SOURCE_DIR}/docs/MANUAL" >> tool_hugehelp.c
+    COMMAND echo "#else" >> tool_hugehelp.c
+    COMMAND env LC_ALL=C "${NROFF}" ${NROFF_MANOPT}
+            "${CURL_SOURCE_DIR}/docs/curl.1" |
+            "${PERL}" "${CMAKE_CURRENT_SOURCE_DIR}/mkhelp.pl" -c
+            "${CURL_SOURCE_DIR}/docs/MANUAL" >> tool_hugehelp.c
+    COMMAND echo "#endif /* HAVE_LIBZ */" >> tool_hugehelp.c
+    DEPENDS
+      "${CURL_SOURCE_DIR}/docs/MANUAL"
+      "${CURL_SOURCE_DIR}/docs/curl.1"
+      "${CMAKE_CURRENT_SOURCE_DIR}/mkhelp.pl"
+      "${CMAKE_CURRENT_SOURCE_DIR}/tool_hugehelp.h"
+    VERBATIM)
+else()
+  add_custom_command(
+    OUTPUT tool_hugehelp.c
+    COMMAND echo "/* built-in manual is disabled, blank function */" > tool_hugehelp.c
+    COMMAND echo "#include \"tool_hugehelp.h\"" >> tool_hugehelp.c
+    COMMAND echo "void hugehelp(void) {}" >> tool_hugehelp.c
+    DEPENDS
+      "${CMAKE_CURRENT_SOURCE_DIR}/tool_hugehelp.h"
+    VERBATIM)
 endif()
 
 transform_makefile_inc("Makefile.inc" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
@@ -28,6 +55,8 @@ include_directories(
   ${CURL_SOURCE_DIR}/lib        # To be able to reach "curl_setup_once.h"
   ${CURL_BINARY_DIR}/lib        # To be able to reach "curl_config.h"
   ${CURL_BINARY_DIR}/include    # To be able to reach "curl/curlbuild.h"
+  # This is needed as tool_hugehelp.c is generated in the binary dir
+  ${CURL_SOURCE_DIR}/src        # To be able to reach "tool_hugehelp.h"
   )
 
 #Build cURL executable