bitbake: siggen: Split out task unique hash

Abstracts the function to get the unique hash for a task. This hash is
used as in place of the taskhash for the purpose of determine how other
tasks depend on this one. Unless overridden, the taskhash is the same as
the unique hash, preserving the original behavior.

[YOCTO #13030]

(Bitbake rev: d0065b34cea81fcadff14b0383779e9559d94508)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/siggen.py

@@ -41,6 +41,9 @@ class SignatureGenerator(object):
     def finalise(self, fn, d, varient):
         return
 
+    def get_unihash(self, task):
+        return self.taskhash[task]
+
     def get_taskhash(self, fn, task, deps, dataCache):
         return "0"
 
@@ -186,7 +189,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
                 continue
             if dep not in self.taskhash:
                 bb.fatal("%s is not in taskhash, caller isn't calling in dependency order?" % dep)
-            data = data + self.taskhash[dep]
+            data = data + self.get_unihash(dep)
             self.runtaskdeps[k].append(dep)
 
         if task in dataCache.file_checksums[fn]:
@@ -261,7 +264,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
             data['file_checksum_values'] = [(os.path.basename(f), cs) for f,cs in self.file_checksum_values[k]]
             data['runtaskhashes'] = {}
             for dep in data['runtaskdeps']:
-                data['runtaskhashes'][dep] = self.taskhash[dep]
+                data['runtaskhashes'][dep] = self.get_unihash(dep)
             data['taskhash'] = self.taskhash[k]
 
         taint = self.read_taint(fn, task, referencestamp)