Bug 1805445 - Centralize defining a new priority in the IPDL compiler. r=nika

This patch makes it so that you only need to add a new element to a list
to add a new priority to the IPDL compiler.

Differential Revision: https://phabricator.services.mozilla.com/D164836

ipc/ipdl/ipdl/ast.py

@@ -9,25 +9,18 @@ NOT_NESTED = 1
 INSIDE_SYNC_NESTED = 2
 INSIDE_CPOW_NESTED = 3
 
-NORMAL_PRIORITY = 1
-INPUT_PRIORITY = 2
-VSYNC_PRIORITY = 3
-MEDIUMHIGH_PRIORITY = 4
-CONTROL_PRIORITY = 5
-
 NESTED_ATTR_MAP = {
     "not": NOT_NESTED,
     "inside_sync": INSIDE_SYNC_NESTED,
     "inside_cpow": INSIDE_CPOW_NESTED,
 }
 
-PRIORITY_ATTR_MAP = {
-    "normal": NORMAL_PRIORITY,
-    "input": INPUT_PRIORITY,
-    "vsync": VSYNC_PRIORITY,
-    "mediumhigh": MEDIUMHIGH_PRIORITY,
-    "control": CONTROL_PRIORITY,
-}
+# Each element of this list is the IPDL source representation of a priority.
+priorityList = ["normal", "input", "vsync", "mediumhigh", "control"]
+
+priorityAttrMap = {src: idx for idx, src in enumerate(priorityList)}
+
+NORMAL_PRIORITY = priorityAttrMap["normal"]
 
 
 class Visitor:
@@ -385,10 +378,11 @@ class MessageDecl(Node):
         return NESTED_ATTR_MAP.get(self.attributes["Nested"].value, NOT_NESTED)
 
     def priority(self):
-        if "Priority" not in self.attributes:
-            return NORMAL_PRIORITY
-
-        return PRIORITY_ATTR_MAP.get(self.attributes["Priority"].value, NORMAL_PRIORITY)
+        if "Priority" in self.attributes:
+            sourcePriority = self.attributes["Priority"].value
+        else:
+            sourcePriority = "normal"
+        return priorityAttrMap.get(sourcePriority, NORMAL_PRIORITY)
 
 
 class Param(Node):

ipc/ipdl/ipdl/lower.py

@@ -1786,6 +1786,10 @@ class _GenerateProtocolCode(ipdl.ast.Visitor):
 
 # --------------------------------------------------
 
+cppPriorityList = list(
+    map(lambda src: src.upper() + "_PRIORITY", ipdl.ast.priorityList)
+)
+
 
 def _generateMessageConstructor(md, segmentSize, protocol, forReply=False):
     if forReply:
@@ -1798,7 +1802,8 @@ def _generateMessageConstructor(md, segmentSize, protocol, forReply=False):
         replyEnum = "NOT_REPLY"
 
     nested = md.decl.type.nested
-    prio = md.decl.type.prio
+    prioEnum = cppPriorityList[md.decl.type.prio]
+
     compress = md.decl.type.compress
 
     routingId = ExprVar("routingId")
@@ -1827,17 +1832,6 @@ def _generateMessageConstructor(md, segmentSize, protocol, forReply=False):
         assert nested == ipdl.ast.INSIDE_CPOW_NESTED
         nestedEnum = "NESTED_INSIDE_CPOW"
 
-    if prio == ipdl.ast.NORMAL_PRIORITY:
-        prioEnum = "NORMAL_PRIORITY"
-    elif prio == ipdl.ast.INPUT_PRIORITY:
-        prioEnum = "INPUT_PRIORITY"
-    elif prio == ipdl.ast.VSYNC_PRIORITY:
-        prioEnum = "VSYNC_PRIORITY"
-    elif prio == ipdl.ast.MEDIUMHIGH_PRIORITY:
-        prioEnum = "MEDIUMHIGH_PRIORITY"
-    else:
-        prioEnum = "CONTROL_PRIORITY"
-
     if md.decl.type.isSync():
         syncEnum = "SYNC"
     else:

ipc/ipdl/ipdl/type.py

@@ -13,6 +13,7 @@ from ipdl.ast import TypeSpec, UnionDecl, UsingStmt, Visitor, StringLiteral
 from ipdl.ast import ASYNC, SYNC, INTR
 from ipdl.ast import IN, OUT, INOUT
 from ipdl.ast import NOT_NESTED, INSIDE_SYNC_NESTED, INSIDE_CPOW_NESTED
+from ipdl.ast import priorityList
 import ipdl.builtin as builtin
 from ipdl.util import hash_str
 
@@ -1290,7 +1291,7 @@ class GatherDecls(TcheckVisitor):
             {
                 "Tainted": None,
                 "Compress": (None, "all"),
-                "Priority": ("normal", "input", "vsync", "mediumhigh", "control"),
+                "Priority": priorityList,
                 "Nested": ("not", "inside_sync", "inside_cpow"),
                 "LegacyIntr": None,
                 "VirtualSendImpl": None,