[freetype2] update-zlib-sources 138a12c 1/2: [meson] Change Zlib configuration option.

[Werner Lemberg]

branch: update-zlib-sources
commit 138a12c2fc1911ed4e71af896bdad7b6962cd106
Author: David Turner <david@freetype.org>
Commit: David Turner <david@freetype.org>

    [meson] Change Zlib configuration option.
    
    * meson_options.txt, meson.build: Change the format of
      the 'zlib' meson build configuration option to be a
      combo with the following choices:
    
    - none: Do not support gzip-compressed streams at all.
    
    - internal: Support gzip-compressed streams using the
      copy of the gzip sources under src/gzip/, this should
      only be used during development to ensure these work
      properly.
    
    - external: Support gzip-compressed streams using the
      'zlib' Meson subproject, linked as a static library.
    
    - system: Support gzip-compressed streams using a system
      installed version of zlib.
    
    - auto: Support gzip-compressed streams using a system
      installed version of zlib, if available, or using the
      'zlib' subproject otherwise. This is the default!
    
    - disabled: backward-compatible alias for 'none'.
    - enabled: backward-compatible alias for 'auto'.
---
 meson.build       | 46 +++++++++++++++++++++++++++++++++++++++-------
 meson_options.txt |  4 ++--
 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/meson.build b/meson.build
index 5efb33d..67fc205 100644
--- a/meson.build
+++ b/meson.build
@@ -246,15 +246,47 @@ ftoption_command = process_header_command
 
 
 # external GZip support
-zlib_dep = dependency('zlib',
-  required: get_option('zlib'),
-  fallback: 'zlib')
+zlib_option = get_option('zlib')
 
-if zlib_dep.found()
-  ftoption_command += ['--enable=FT_CONFIG_OPTION_SYSTEM_ZLIB']
+# Backwards-compatible aliases.
+if zlib_option == 'disabled'
+  zlib_option = 'none'
+elif zlib_option == 'enabled'
+  zlib_option = 'auto'
+endif
+
+if zlib_option == 'auto'
+  # First try to find a system installation, otherwise
+  # fallback to the subproject.
+  zlib_dep = dependency('zlib', required: false)
+  if zlib_dep.found()
+    zlib_option = 'system'
+  else
+    zlib_option = 'external'
+  endif
+endif
+
+if zlib_option == 'none'
+  ftoption_command += [ '--disable=FT_CONFIG_OPTION_USE_ZLIB' ]
+elif zlib_option == 'internal'
+  ftoption_command += [ '--enable=FT_CONFIG_OPTION_USE_ZLIB' ]
+elif zlib_option == 'external'
+  ftoption_command += [ '--enable=FT_CONFIG_OPTION_USE_ZLIB' ]
+  zlib_project = subproject('zlib',
+    required: true,
+    default_options: 'default_library=static')
+  zlib_dep = zlib_project.get_variable('zlib_dep')
+  ft2_deps += [zlib_dep]
+elif zlib_option == 'system'
+  zlib_dep = dependency('zlib', required: true)
+  assert(zlib_dep.found(), 'Could not find system zlib installation!')
+  ftoption_command += [
+    '--enable=FT_CONFIG_OPTION_USE_ZLIB',
+    '--enable=FT_CONFIG_OPTION_SYSTEM_ZLIB',
+  ]
   ft2_deps += [zlib_dep]
 else
-  ftoption_command += ['--disable=FT_CONFIG_OPTION_SYSTEM_ZLIB']
+  assert(false, 'Invalid zlib option ' + zlib_option)
 endif
 
 # BZip2 support
@@ -400,7 +432,7 @@ gen_docs = custom_target('freetype2 reference 
documentation',
 summary({'OS': host_machine.system(),
         }, section: 'Operating System')
 
-summary({'Zlib': zlib_dep.found() ? 'external' : 'internal',
+summary({'Zlib': zlib_option,
          'Bzip2': bzip2_dep.found() ? 'yes' : 'no',
          'Png': libpng_dep.found() ? 'yes' : 'no',
          'Harfbuzz': harfbuzz_dep.found() ? 'yes' : 'no',
diff --git a/meson_options.txt b/meson_options.txt
index 375eb71..7f2879a 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -46,8 +46,8 @@ option('tests',
   description: 'Enable FreeType unit and regression tests')
 
 option('zlib',
-  type: 'feature',
-  value: 'auto',
+  type: 'combo',
+  choices: ['auto', 'none', 'internal', 'external', 'system', 'disabled', 
'enabled'],
   description: 'Support reading gzip-compressed font files')
 
 # EOF