[OE-core] package_rpm.bbclass: Replace shell provides/requires script with python version

[Richard Purdie]

The existing shell script is a fork bomb and forks off hundreds of
grep/cur/wc calls as it reads from its input stream and iterates over
the file data table for each line of input. This patch replaces the
shell code with python code which doesn't exec anything and hence runs
much faster without the exec() overhead. This speeds up rpm packaging
considerably, as can be measured simply by timing it, or watching the
processor utilisation.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
diff --git a/meta/classes/package_rpm.bbclass b/meta/classes/package_rpm.bbclass
index ffe3b31..d90976b 100644
--- a/meta/classes/package_rpm.bbclass
+++ b/meta/classes/package_rpm.bbclass
@@ -1004,8 +1004,9 @@ python do_package_rpm () {
 
 	# Construct per file dependencies file
 	def dump_filerdeps(varname, outfile, d):
-		outfile.write("#!/bin/sh\n")
-		outfile.write("\n# Dependency table\n")
+		outfile.write("#!/usr/bin/env python\n\n")
+		outfile.write("# Dependency table\n")
+		outfile.write('deps = {\n')
 		for pkg in packages.split():
 			dependsflist_key = 'FILE' + varname + 'FLIST' + "_" + pkg
 			dependsflist = (d.getVar(dependsflist_key, True) or "")
@@ -1018,7 +1019,7 @@ python do_package_rpm () {
 				file = file.replace("@tab@", "\t")
 				file = file.replace("@space@", " ")
 				file = file.replace("@at@", "@")
-				outfile.write("#" + pkgd + file + "\t")
+				outfile.write('"' + pkgd + file + '" : "')
 				for dep in depends_dict:
 					ver = depends_dict[dep]
 					if dep and ver:
@@ -1027,12 +1028,15 @@ python do_package_rpm () {
 						outfile.write(dep + " " + ver + " ")
 					else:
 						outfile.write(dep + " ")
-				outfile.write("\n")
-		outfile.write("\n\nwhile read file_name ; do\n")
-		outfile.write("\tlength=$(echo \"#${file_name}\t\" | wc -c )\n")
-		outfile.write("\tline=$(grep \"^#${file_name}\t\" $0 | cut -c ${length}- )\n")
-		outfile.write("\tprintf \"%s\\n\" ${line}\n")
-		outfile.write("done\n")
+				outfile.write('",\n')
+		outfile.write('}\n\n')
+		outfile.write("import sys\n")
+		outfile.write("while 1:\n")
+		outfile.write("\tline = sys.stdin.readline().strip()\n")
+		outfile.write("\tif not line:\n")
+		outfile.write("\t\tsys.exit(0)\n")
+		outfile.write("\tif line in deps:\n")
+		outfile.write("\t\tprint(deps[line] + '\\n')\n")
 
 	# OE-core dependencies a.k.a. RPM requires
 	outdepends = workdir + "/" + srcname + ".requires"