meson: fix nativesdk-meson for multilib SDKs

Multilib SDKs differ only in the environment variables set, so nativesdk-meson's
setup script needs to write a cross file for each environment.

Rename the shipped meson.cross to meson.cross.template, as it cannot be used
directly.  Now that post-relocate scripts are called once for each environment,
the generated meson.cross can be prefixed with TARGET_PREFIX to ensure it is
unique.

Finally rewrite the setup script to use string.Template to perform the expansion
instead of hand-coding the logic.

Signed-off-by: Ross Burton <ross.burton@intel.com>

1 files changed, 19 insertions, 50 deletions

diff --git a/meta/recipes-devtools/meson/meson/meson-setup.py b/meta/recipes-devtools/meson/meson/meson-setup.py
index a9749eae9d..808e2a062f 100755
--- a/meta/recipes-devtools/meson/meson/meson-setup.py
+++ b/meta/recipes-devtools/meson/meson/meson-setup.py
@@ -1,62 +1,31 @@
 #!/usr/bin/env python3
 
 import os
+import string
 import sys
 
-def bail(msg):
-    print(msg, file=sys.stderr)
-    sys.exit(1)
-
-_MARKER = '@@'
-def transform_line(line):
-    # Substitute any special markers of this form:
-    # @@ENV@@
-    # with the value of ENV, split into meson array syntax.
-    start = line.find(_MARKER)
-    if start == -1:
-        return line
-
-    end = line.rfind(_MARKER)
-    if end == start:
-        return line
-
-    # Lookup value of the env var.
-    var = line[start+len(_MARKER):end]
-    try:
-        val = os.environ[var]
-    except KeyError:
-        bail('cannot generate meson.cross; env var %s not set' % var)
+class Template(string.Template):
+    delimiter = "@"
 
-    # Transform into meson array.
-    val = ["'%s'" % x for x in val.split()]
-    val = ', '.join(val)
-    val = '[%s]' % val
+class Environ():
+    def __getitem__(self, name):
+        val = os.environ[name]
+        val = ["'%s'" % x for x in val.split()]
+        val = ', '.join(val)
+        val = '[%s]' % val
+        return val
 
-    before = line[:start]
-    after = line[end+len(_MARKER):]
-
-    return '%s%s%s' % (before, val, after)
-
-# Make sure this is really an SDK extraction environment.
 try:
     sysroot = os.environ['OECORE_NATIVE_SYSROOT']
 except KeyError:
-    bail('OECORE_NATIVE_SYSROOT env var must be set')
-
-cross_file = os.path.join(sysroot, 'usr/share/meson/meson.cross')
-tmp_cross_file = '%s.tmp' % cross_file
+    print("Not in environment setup, bailing")
+    sys.exit(1)
 
-# Read through and transform the current meson.cross.
-lines = []
-with open(cross_file, 'r') as f:
-    for line in f:
-        lines.append(transform_line(line))
+template_file = os.path.join(sysroot, 'usr/share/meson/meson.cross.template')
+cross_file = os.path.join(sysroot, 'usr/share/meson/%smeson.cross' % os.environ["TARGET_PREFIX"])
 
-# Write the transformed result to a tmp file and atomically rename it. In case
-# we crash during the file write, we don't want an invalid meson.cross file.
-with open(tmp_cross_file, 'w') as f:
-    for line in lines:
-        f.write(line)
-    f.flush()
-    os.fdatasync(f.fileno())
-os.rename(tmp_cross_file, cross_file)
+with open(template_file) as in_file:
+    template = in_file.read()
+    output = Template(template).substitute(Environ())
+    with open(cross_file, "w") as out_file:
+        out_file.write(output)