tools/generate-wire.py: --printwire option to create print routines.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tools/generate-wire.py

@@ -217,6 +217,25 @@ towire_impl_templ = """u8 *towire_{name}(const tal_t *ctx{args})
 	return memcheck(p, tal_count(p));
 }}
 """
+
+printwire_header_templ = """void printwire_{name}(const u8 *cursor);
+"""
+printwire_impl_templ = """void printwire_{name}(const u8 *cursor)
+{{
+        size_t plen = tal_len(cursor);
+
+	if (fromwire_u16(&cursor, &plen) != {enum.name}) {{
+                printf("WRONG TYPE?!\\n");
+                return;
+        }}
+
+{subcalls}
+
+        if (plen != 0)
+                printf("EXTRA: %s\\n", tal_hexstr(NULL, cursor, plen));
+}}
+"""
+
 class Message(object):
     def __init__(self,name,enum,comments):
         self.name = name
@@ -391,6 +410,89 @@ class Message(object):
             subcalls='\n'.join(subcalls),
         )
 
+    def add_truncate_check(self, subcalls, indent='\t'):
+        # Report if truncated, otherwise print.
+        subcalls.append(indent + 'if (!cursor) {')
+        subcalls.append(indent + '\tprintf("**TRUNCATED**\\n");')
+        subcalls.append(indent + '\treturn;')
+        subcalls.append(indent + '}')
+
+    def print_printwire_array(self, subcalls, basetype, f, num_elems):
+        if f.has_array_helper():
+            subcalls.append('\tprintwire_{}_array(&cursor, &plen, {});'
+                            .format(basetype, num_elems))
+        else:
+            subcalls.append('\tprintf("[");')
+            subcalls.append('\tfor (size_t i = 0; i < {}; i++) {{'
+                            .format(num_elems))
+            subcalls.append('\t\t{} v;'.format(f.fieldtype.name));
+            if f.fieldtype.is_assignable():
+                subcalls.append('\t\tv = fromwire_{}(&cursor, plen);'
+                                .format(name,basetype))
+            else:
+                # We don't handle this yet!
+                assert not basetype in varlen_structs
+
+                subcalls.append('\t\tfromwire_{}(&cursor, &plen, &v);'
+                                .format(basetype))
+
+            self.add_truncate_check(subcalls, indent='\t\t')
+
+            subcalls.append('\t\tprintwire_{}(&v);'.format(basetype))
+            subcalls.append('\t}')
+            subcalls.append('\tprintf("]");')
+
+    def print_printwire(self,is_header):
+        template = printwire_header_templ if is_header else printwire_impl_templ
+        fields = ['\t{} {};\n'.format(f.fieldtype.name, f.name) for f in self.fields if f.is_len_var]
+
+        subcalls = []
+        for f in self.fields:
+            basetype=f.basetype()
+
+            for c in f.comments:
+                subcalls.append('\t/*{} */'.format(c))
+
+            if f.is_len_var:
+                subcalls.append('\t{} {} = fromwire_{}(&cursor, &plen);'
+                                .format(f.fieldtype.name, f.name, basetype))
+                self.add_truncate_check(subcalls)
+                continue
+
+            subcalls.append('\tprintf("{}=");'.format(f.name))
+            if f.is_padding():
+                subcalls.append('\tprintwire_pad(&cursor, &plen, {});'
+                                .format(f.num_elems))
+                self.add_truncate_check(subcalls)
+            elif f.is_array():
+                self.print_printwire_array(subcalls, basetype, f, f.num_elems)
+                self.add_truncate_check(subcalls)
+            elif f.is_variable_size():
+                self.print_printwire_array(subcalls, basetype, f, f.lenvar)
+                self.add_truncate_check(subcalls)
+            else:
+                if f.is_assignable():
+                    subcalls.append('\t{} {} = fromwire_{}(&cursor, &plen);'
+                                    .format(f.fieldtype.name, f.name, basetype))
+                else:
+                    # Don't handle these yet.
+                    assert not basetype in varlen_structs
+                    subcalls.append('\t{} {};'.
+                                    format(f.fieldtype.name, f.name));
+                    subcalls.append('\tfromwire_{}(&cursor, &plen, &{});'
+                                    .format(basetype, f.name))
+
+                self.add_truncate_check(subcalls)
+                subcalls.append('\tprintwire_{}(&{});'
+                                .format(basetype, f.name))
+
+        return template.format(
+            name=self.name,
+            fields=''.join(fields),
+            enum=self.enum,
+            subcalls='\n'.join(subcalls)
+        )
+
 def find_message(messages, name):
     for m in messages:
         if m.name == name:
@@ -416,6 +518,7 @@ def find_message_with_option(messages, optional_messages, name, option):
 parser = argparse.ArgumentParser(description='Generate C from CSV')
 parser.add_argument('--header', action='store_true', help="Create wire header")
 parser.add_argument('--bolt', action='store_true', help="Generate wire-format for BOLT")
+parser.add_argument('--printwire', action='store_true', help="Create print routines")
 parser.add_argument('headerfilename', help='The filename of the header')
 parser.add_argument('enumname', help='The name of the enum to produce')
 parser.add_argument('files', nargs='*', help='Files to read in (or stdin)')
@@ -509,8 +612,50 @@ const char *{enumname}_name(int e)
 {func_decls}
 """
 
+print_header_template = """/* This file was generated by generate-wire.py */
+/* Do not modify this file! Modify the _csv file it was generated from. */
+#ifndef LIGHTNING_{idem}
+#define LIGHTNING_{idem}
+#include <ccan/tal/tal.h>
+#include <devtools/print_wire.h>
+{includes}
+
+void print_message(const u8 *msg);
+
+{func_decls}
+#endif /* LIGHTNING_{idem} */
+"""
+
+print_template = """/* This file was generated by generate-wire.py */
+/* Do not modify this file! Modify the _csv file it was generated from. */
+#include "{headerfilename}"
+#include <ccan/mem/mem.h>
+#include <ccan/tal/str/str.h>
+#include <common/utils.h>
+#include <stdio.h>
+
+void print_message(const u8 *msg)
+{{
+	switch ((enum {enumname})fromwire_peektype(msg)) {{
+	{printcases}
+	}}
+
+	printf("UNKNOWN: %s\\n", tal_hex(msg, msg));
+}}
+
+{func_decls}
+"""
+
 idem = re.sub(r'[^A-Z]+', '_', options.headerfilename.upper())
-template = header_template if options.header else impl_template
+if options.printwire:
+    if options.header:
+        template = print_header_template
+    else:
+        template = print_template
+elif options.header:
+    template = header_template
+else:
+    template = impl_template
 
 # Dump out enum, sorted by value order.
 enums = ""
@@ -520,16 +665,22 @@ for m in messages:
     enums += '\t{} = {},\n'.format(m.enum.name, m.enum.value)
 includes = '\n'.join(includes)
 cases = ['case {enum.name}: return "{enum.name}";'.format(enum=m.enum) for m in messages]
+printcases = ['case {enum.name}: printf("{enum.name}:\\n"); printwire_{name}(msg); return;'.format(enum=m.enum,name=m.name) for m in messages]
 
-fromwire_decls = [m.print_fromwire(options.header) for m in messages + messages_with_option]
+if options.printwire:
-towire_decls = [m.print_towire(options.header) for m in messages + messages_with_option]
+    decls = [m.print_printwire(options.header) for m in messages + messages_with_option]
+else:
+    fromwire_decls = [m.print_fromwire(options.header) for m in messages + messages_with_option]
+    towire_decls = towire_decls = [m.print_towire(options.header) for m in messages + messages_with_option]
+    decls = fromwire_decls + towire_decls
 
 print(template.format(
     headerfilename=options.headerfilename,
     cases='\n\t'.join(cases),
+    printcases='\n\t'.join(printcases),
     idem=idem,
     includes=includes,
     enumname=options.enumname,
     enums=enums,
-    func_decls='\n'.join(fromwire_decls + towire_decls),
+    func_decls='\n'.join(decls),
 ))