1 files changed, 107 insertions, 117 deletions

diff --git a/lib9p/idl.gen b/lib9p/idl.gen
index 1dafef9..1f5e48c 100755
--- a/lib9p/idl.gen
+++ b/lib9p/idl.gen
@@ -9,19 +9,14 @@ import enum
 import os.path
 import re
 from abc import ABC, abstractmethod
-from typing import Callable, Literal, TypeAlias, TypeVar
+from typing import Callable, Final, Literal, TypeAlias, TypeVar, cast
 
 # This strives to be "general-purpose" in that it just acts on the
 # *.9p inputs; but (unfortunately?) there are a few special-cases in
 # this script, marked with "SPECIAL".
 
-T = TypeVar("T")
-
 # Types ########################################################################
 
-Type: TypeAlias = "Primitive | Number | Bitfield | Struct | Message"
-
-
 class Primitive(enum.Enum):
     u8 = 1
     u16 = 2
@@ -133,7 +128,7 @@ class StructMember:
     # from left-to-right when parsing
     cnt: str | None = None
     name: str
-    typ: Type
+    typ: 'Type'
     max: Expr
     val: Expr
 
@@ -178,6 +173,10 @@ class Message(Struct):
         return self.members[1].val.tokens[0].val
 
 
+Type: TypeAlias = Primitive | Number | Bitfield | Struct | Message
+#type Type = Primitive | Number | Bitfield | Struct | Message # Change to this once we have Python 3.13
+T = TypeVar("T", Number, Bitfield, Struct, Message)
+
 # Parse *.9p ###################################################################
 
 re_priname = "(?:1|2|4|8)"  # primitive names
@@ -235,7 +234,7 @@ def parse_expr(expr: str) -> Expr:
     ret = Expr()
     for tok in re.split("([-+])", expr):
         if tok == "-" or tok == "+":
-            ret.tokens += [ExprOp(tok)]
+            ret.tokens += [ExprOp(cast(Literal["-", "+"], tok))]
         elif re.fullmatch("[0-9]+", tok):
             ret.tokens += [ExprLit(int(tok))]
         else:
@@ -292,7 +291,9 @@ re_line_version = f"version\\s+{re_string('version')}"
 re_line_import = f"from\\s+(?P<file>\\S+)\\s+import\\s+(?P<syms>{re_impname}(?:\\s*,\\s*{re_impname})*)"
 re_line_num = f"num\\s+(?P<name>{re_symname})\\s*=\\s*(?P<prim>{re_priname})"
 re_line_bitfield = f"bitfield\\s+(?P<name>{re_symname})\\s*=\\s*(?P<prim>{re_priname})"
-re_line_bitfield_ = f"bitfield\\s+(?P<name>{re_symname})\\s*\\+=\\s*{re_string('member')}"
+re_line_bitfield_ = (
+    f"bitfield\\s+(?P<name>{re_symname})\\s*\\+=\\s*{re_string('member')}"
+)
 re_line_struct = (
     f"struct\\s+(?P<name>{re_symname})\\s*(?P<op>\\+?=)\\s*{re_string('members')}"
 )
@@ -372,6 +373,7 @@ def parse_file(
             elif m := re.fullmatch(re_line_bitfield, line):
                 bf = Bitfield()
                 bf.name = m.group("name")
+                bf.in_versions.add(version)
 
                 prim = env[m.group("prim")]
                 assert isinstance(prim, Primitive)
@@ -454,10 +456,9 @@ def c_ver_enum(idprefix: str, ver: str) -> str:
     return f"{idprefix.upper()}VER_{ver.replace('.', '_')}"
 
 
-def c_ver_ifdef(idprefix: str, versions: set[str]) -> str:
+def c_ver_ifdef(versions: set[str]) -> str:
     return " || ".join(
-        f"defined(CONFIG_{idprefix.upper()}ENABLE_{c_ver_enum('', v)})"
-        for v in sorted(versions)
+        f"defined(CONFIG_9P_ENABLE_{v.replace('.', '_')})" for v in sorted(versions)
     )
 
 
@@ -485,7 +486,51 @@ def c_typename(idprefix: str, typ: Type) -> str:
             raise ValueError(f"not a type: {typ.__class__.__name__}")
 
 
+_ifdef_stack: list[str | None] = []
+
+
+def ifdef_push(n: int, _newval: str) -> str:
+    # Grow the stack as needed
+    global _ifdef_stack
+    while len(_ifdef_stack) < n:
+        _ifdef_stack += [None]
+
+    # Set some variables
+    parentval: str | None = None
+    for x in _ifdef_stack[:-1]:
+        if x is not None:
+            parentval = x
+    oldval = _ifdef_stack[-1]
+    newval: str | None = _newval
+    if newval == parentval:
+        newval = None
+
+    # Put newval on the stack.
+    _ifdef_stack[-1] = newval
+
+    # Build output.
+    ret = ""
+    if newval != oldval:
+        if oldval is not None:
+            ret += f"#endif /* {oldval} */\n"
+        if newval is not None:
+            ret += f"#if {newval}\n"
+    return ret
+
+def ifdef_pop(n: int) -> str:
+    global _ifdef_stack
+    ret = ""
+    while len(_ifdef_stack) > n:
+        if _ifdef_stack[-1] is not None:
+            ret += f"#endif /* {_ifdef_stack[-1]} */\n"
+        _ifdef_stack = _ifdef_stack[:-1]
+    return ret
+
+
 def gen_h(idprefix: str, versions: set[str], typs: list[Type]) -> str:
+    global _ifdef_stack
+    _ifdef_stack = []
+
     ret = f"""/* Generated by `{' '.join(sys.argv)}`.  DO NOT EDIT!  */
 
 #ifndef _LIB9P_9P_H_
@@ -495,36 +540,6 @@ def gen_h(idprefix: str, versions: set[str], typs: list[Type]) -> str:
 #include <stdint.h> /* for uint{{n}}_t types */
 """
 
-    _ifdef: list[str] = []
-
-    def push_ifdef(v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        ret += f"#if {v}\n"
-        _ifdef += [v]
-
-    def pop_ifdef(n: int) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        while len(_ifdef) > n:
-            ret += f"#endif /* {_ifdef[-1]}\n"
-            _ifdef = _ifdef[:-1]
-
-    def set_ifdef(v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        if v != _ifdef[-1]:
-            ret += f"#elif {v}\n"
-            _ifdef[-1] = v
-
-    def pushorset_ifdef(n: int, v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        if len(_ifdef) < n:
-            push_ifdef(v)
-        else:
-            set_ifdef(v)
-
     ret += f"""
 /* versions *******************************************************************/
 
@@ -534,10 +549,10 @@ enum {idprefix}version {{
     verwidth = max(len(v) for v in fullversions)
     for ver in fullversions:
         if ver in versions:
-            pushorset_ifdef(1, c_ver_ifdef(idprefix, {ver}))
+            ret += ifdef_push(1, c_ver_ifdef({ver}))
         ret += f"\t{c_ver_enum(idprefix, ver)},"
         ret += (" " * (verwidth - len(ver))) + ' /* "' + ver.split()[0] + '" */\n'
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
     ret += f"\t{c_ver_enum(idprefix, 'NUM')},\n"
     ret += "};\n"
     ret += "\n"
@@ -548,7 +563,7 @@ enum {idprefix}version {{
 """
     for typ in [typ for typ in typs if not isinstance(typ, Message)]:
         ret += "\n"
-        pushorset_ifdef(1, c_ver_ifdef(idprefix, typ.in_versions))
+        ret += ifdef_push(1, c_ver_ifdef(typ.in_versions))
         match typ:
             case Number():
                 ret += f"typedef {c_typename(idprefix, typ.prim)} {c_typename(idprefix, typ)};\n"
@@ -556,7 +571,7 @@ enum {idprefix}version {{
                 ret += f"typedef {c_typename(idprefix, typ.prim)} {c_typename(idprefix, typ)};\n"
                 names = [
                     *reversed(
-                        [typ.bits[n] or f"_UNUSED_{n}" for n in range(0, len(typ.bits))]
+                        [typ.bits[n] or f" {n}" for n in range(0, len(typ.bits))]
                     ),
                     "",
                     *[k for k in typ.names if k not in typ.bits],
@@ -567,21 +582,21 @@ enum {idprefix}version {{
                 for name in names:
                     if name == "":
                         ret += "\n"
-                        continue
-                    pushorset_ifdef(
-                        2, c_ver_ifdef(idprefix, typ.names[name].in_versions)
-                    )
-                    if name.startswith("_"):
-                        c_name = f"_{idprefix.upper()}{typ.name.upper()}_{name[1:]}"
-                    else:
-                        c_name = f"{idprefix.upper()}{typ.name.upper()}_{name}"
-                    if name in typ.names:
-                        val = typ.names[name].val
+                    elif name.startswith(" "):
+                        ret += ifdef_push(2, c_ver_ifdef(typ.in_versions))
+                        sp = ' '*(len('#  define ')+len(idprefix)+len(typ.name)+1+namewidth+2-len("/* unused"))
+                        ret += f"/* unused{sp}(({c_typename(idprefix, typ)})(1<<{name[1:]})) */\n"
                     else:
-                        assert name.startswith("_UNUSED_")
-                        val = f"1<<{name[len('_UNUSED_'):]}"
-                    ret += f"#define {c_name}{' '*(namewidth-len(name))}  (({c_typename(idprefix, typ)})({val}))\n"
-                pop_ifdef(1)
+                        ret += ifdef_push(2, c_ver_ifdef(typ.names[name].in_versions))
+                        if name.startswith("_"):
+                            c_name = f"_{idprefix.upper()}{typ.name.upper()}_{name[1:]}"
+                        else:
+                            c_name = f"{idprefix.upper()}{typ.name.upper()}_{name}"
+                        sp1 = '  ' if _ifdef_stack[-1] else ''
+                        sp2 = ' ' if _ifdef_stack[-1] else '   '
+                        sp3 = ' '*(2+namewidth-len(name))
+                        ret += f"#{sp1}define{sp2}{c_name}{sp3}(({c_typename(idprefix, typ)})({typ.names[name].val}))\n"
+                ret += ifdef_pop(1)
             case Struct():
                 typewidth = max(len(c_typename(idprefix, m.typ)) for m in typ.members)
 
@@ -589,14 +604,14 @@ enum {idprefix}version {{
                 for member in typ.members:
                     if member.val:
                         continue
-                    pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
+                    ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
                     c_type = c_typename(idprefix, member.typ)
                     if (typ.name in ["d", "s"]) and member.cnt:  # SPECIAL
                         c_type = "char"
                     ret += f"\t{c_type.ljust(typewidth)}  {'*' if member.cnt else ' '}{member.name};\n"
-                pop_ifdef(1)
+                ret += ifdef_pop(1)
                 ret += "};\n"
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
 
     ret += """
 /* messages *******************************************************************/
@@ -605,16 +620,16 @@ enum {idprefix}version {{
     ret += f"enum {idprefix}msg_type {{ /* uint8_t */\n"
     namewidth = max(len(msg.name) for msg in typs if isinstance(msg, Message))
     for msg in [msg for msg in typs if isinstance(msg, Message)]:
-        pushorset_ifdef(1, c_ver_ifdef(idprefix, msg.in_versions))
+        ret += ifdef_push(1, c_ver_ifdef(msg.in_versions))
         ret += f"\t{idprefix.upper()}TYP_{msg.name.ljust(namewidth)} = {msg.msgid},\n"
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
     ret += "};\n"
     ret += "\n"
     ret += f"const char *{idprefix}msg_type_str(enum {idprefix}msg_type);\n"
 
     for msg in [msg for msg in typs if isinstance(msg, Message)]:
         ret += "\n"
-        pushorset_ifdef(1, c_ver_ifdef(idprefix, msg.in_versions))
+        ret += ifdef_push(1, c_ver_ifdef(msg.in_versions))
         ret += c_typename(idprefix, msg) + " {"
         if not msg.members:
             ret += "};\n"
@@ -626,11 +641,11 @@ enum {idprefix}version {{
         for member in msg.members:
             if member.val:
                 continue
-            pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
+            ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
             ret += f"\t{c_typename(idprefix, member.typ).ljust(typewidth)}  {'*' if member.cnt else ' '}{member.name};\n"
-        pop_ifdef(1)
+        ret += ifdef_pop(1)
         ret += "};\n"
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
 
     return ret
 
@@ -651,6 +666,9 @@ def c_expr(expr: Expr) -> str:
 
 
 def gen_c(idprefix: str, versions: set[str], typs: list[Type]) -> str:
+    global _ifdef_stack
+    _ifdef_stack = []
+
     ret = f"""/* Generated by `{' '.join(sys.argv)}`.  DO NOT EDIT!  */
 
 #include <assert.h>
@@ -664,36 +682,6 @@ def gen_c(idprefix: str, versions: set[str], typs: list[Type]) -> str:
 #include "internal.h"
 """
 
-    _ifdef: list[str] = []
-
-    def push_ifdef(v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        ret += f"#if {v}\n"
-        _ifdef += [v]
-
-    def pop_ifdef(n: int) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        while len(_ifdef) > n:
-            ret += f"#endif /* {_ifdef[-1]}\n"
-            _ifdef = _ifdef[:-1]
-
-    def set_ifdef(v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        if v != _ifdef[-1]:
-            ret += f"#elif {v}\n"
-            _ifdef[-1] = v
-
-    def pushorset_ifdef(n: int, v: str) -> None:
-        nonlocal _ifdef
-        nonlocal ret
-        if len(_ifdef) < n:
-            push_ifdef(v)
-        else:
-            set_ifdef(v)
-
     def used(arg: str) -> str:
         return arg
 
@@ -707,9 +695,10 @@ def gen_c(idprefix: str, versions: set[str], typs: list[Type]) -> str:
 static const char *version_strs[{c_ver_enum(idprefix, 'NUM')}] = {{
 """
     for ver in ["unknown", *sorted(versions)]:
-        pushorset_ifdef(1, c_ver_ifdef(idprefix, {ver}))
+        if ver in versions:
+            ret += ifdef_push(1, c_ver_ifdef({ver}))
         ret += f'\t[{c_ver_enum(idprefix, ver)}] = "{ver}",\n'
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
     ret += "};\n"
     ret += f"""
 const char *{idprefix}version_str(enum {idprefix}version ver) {{
@@ -774,7 +763,7 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
         inline = "FLATTEN" if isinstance(typ, Message) else "ALWAYS_INLINE"
         argfn = unused if (isinstance(typ, Struct) and not typ.members) else used
         ret += "\n"
-        pushorset_ifdef(1, c_ver_ifdef(idprefix, typ.in_versions))
+        ret += ifdef_push(1, c_ver_ifdef(typ.in_versions))
         ret += f"static {inline} bool validate_{typ.name}(struct _validate_ctx *{argfn('ctx')}) {{\n"
 
         if typ.name == "d":  # SPECIAL
@@ -811,7 +800,7 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
                 ret += f"\tstatic const {c_typename(idprefix, typ)} masks[{c_ver_enum(idprefix, 'NUM')}] = {{\n"
                 verwidth = max(len(ver) for ver in versions)
                 for ver in sorted(versions):
-                    pushorset_ifdef(2, c_ver_ifdef(idprefix, {ver}))
+                    ret += ifdef_push(2, c_ver_ifdef({ver}))
                     ret += (
                         f"\t\t[{c_ver_enum(idprefix, ver)}]{' '*(verwidth-len(ver))} = 0b"
                         + "".join(
@@ -820,7 +809,7 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
                         )
                         + ",\n"
                     )
-                pop_ifdef(1)
+                ret += ifdef_pop(1)
                 ret += "\t};\n"
                 ret += (
                     f"\t{c_typename(idprefix, typ)} mask = masks[ctx->ctx->version];\n"
@@ -839,10 +828,10 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
 
                 # Pass 1
                 for member in typ.members:
-                    pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
                     if member.max or member.val:
+                        ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
                         ret += f"\t{c_typename(idprefix, member.typ)} {member.name};\n"
-                pop_ifdef(1)
+                ret += ifdef_pop(1)
 
                 # Pass 2
                 mark_offset: set[str] = set()
@@ -857,8 +846,8 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
                 ret += "\treturn false\n"
                 prev_size: int | None = None
                 for member in typ.members:
-                    pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
-                    ret += f"\n\t|| "
+                    ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
+                    ret += f"\t    || "
                     if member.in_versions != typ.in_versions:
                         ret += "( " + c_ver_cond(idprefix, member.in_versions) + " && "
                     if member.cnt is not None:
@@ -879,23 +868,24 @@ static ALWAYS_INLINE bool _validate_list(struct _validate_ctx *ctx,
                             ret += f" || ({{ {member.name} = decode_u{bits}le(&ctx->net_bytes[ctx->net_offset-{bytes}]); false; }}))"
                     if member.in_versions != typ.in_versions:
                         ret += " )"
+                    ret += "\n"
                     prev_size = member.static_size
 
                 # Pass 4
                 for member in typ.members:
                     if member.max:
-                        pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
-                        ret += f"\n\t|| ({{ uint32_t max = {c_expr(member.max)}; (((uint32_t){member.name}) > max) &&\n"
-                        ret += f'\n\t       lib9p_errorf(ctx->ctx, LINUX_EBADMSG, "{member.name} value too large (%"PRIu32" > %"PRIu32")", {member.name}, max); }})\n'
+                        ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
+                        ret += f"\n\t    || ({{ uint32_t max = {c_expr(member.max)}; (((uint32_t){member.name}) > max) &&\n"
+                        ret += f'\n\t           lib9p_errorf(ctx->ctx, LINUX_EBADMSG, "{member.name} value too large (%"PRIu32" > %"PRIu32")", {member.name}, max); }})\n'
                     if member.val:
-                        pushorset_ifdef(2, c_ver_ifdef(idprefix, member.in_versions))
-                        ret += f"\n\t|| ({{ uint32_t exp = {c_expr(member.val)}; (((uint32_t){member.name}) != exp) &&\n"
-                        ret += f'\n\t       lib9p_errorf(ctx->ctx, LINUX_EBADMSG, "{member.name} value wrong (actual:%"PRIu32" != correct:%"PRIu32")", (uint32_t){member.name}, exp); }})\n'
+                        ret += ifdef_push(2, c_ver_ifdef(member.in_versions))
+                        ret += f"\n\t    || ({{ uint32_t exp = {c_expr(member.val)}; (((uint32_t){member.name}) != exp) &&\n"
+                        ret += f'\n\t           lib9p_errorf(ctx->ctx, LINUX_EBADMSG, "{member.name} value wrong (actual:%"PRIu32" != correct:%"PRIu32")", (uint32_t){member.name}, exp); }})\n'
 
-                pop_ifdef(1)
-                ret += "\t;\n"
+                ret += ifdef_pop(1)
+                ret += "\t    ;\n"
         ret += "}\n"
-    pop_ifdef(0)
+    ret += ifdef_pop(0)
 
     #     # unmarshal_* ##############################################################
     #     ret += """