Ported upb to C89, for greater portability.

A large part of this change contains surface-level
porting, like moving variable declarations to the
top of the block.

However there are a few more substantial things too:

- moved internal-only struct definitions to a separate
  file (structdefs.int.h), for greater encapsulation
  and ABI compatibility.

- removed the UPB_UPCAST macro, since it requires access
  to the internal-only struct definitions.  Replaced uses
  with calls to inline, type-safe casting functions.

- removed the UPB_DEFINE_CLASS/UPB_DEFINE_STRUCT macros.
  Class and struct definitions are now more explicit -- you
  get to see the actual class/struct keywords in the source.
  The casting convenience functions have been moved into
  UPB_DECLARE_DERIVED_TYPE() and UPB_DECLARE_DERIVED_TYPE2().

- the new way that we duplicate base methods in derived types
  is also more convenient and requires less duplication.
  It is also less greppable, but hopefully that is not
  too big a problem.

Compiler flags (-std=c89 -pedantic) should help to rigorously
enforce that the code is free of C99-isms.

A few functions are not available in C89 (strtoll).  There
are temporary, hacky solutions in place.

1 files changed, 38 insertions, 26 deletions

diff --git a/upb/pb/textprinter.c b/upb/pb/textprinter.c
index 07f951d..b772af3 100644
--- a/upb/pb/textprinter.c
+++ b/upb/pb/textprinter.c
@@ -13,6 +13,7 @@
 #include <ctype.h>
 #include <float.h>
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -50,22 +51,24 @@ static int endfield(upb_textprinter *p) {
 
 static int putescaped(upb_textprinter *p, const char *buf, size_t len,
                       bool preserve_utf8) {
-  // Based on CEscapeInternal() from Google's protobuf release.
+  /* Based on CEscapeInternal() from Google's protobuf release. */
   char dstbuf[4096], *dst = dstbuf, *dstend = dstbuf + sizeof(dstbuf);
   const char *end = buf + len;
 
-  // I think hex is prettier and more useful, but proto2 uses octal; should
-  // investigate whether it can parse hex also.
+  /* I think hex is prettier and more useful, but proto2 uses octal; should
+   * investigate whether it can parse hex also. */
   const bool use_hex = false;
-  bool last_hex_escape = false; // true if last output char was \xNN
+  bool last_hex_escape = false; /* true if last output char was \xNN */
 
   for (; buf < end; buf++) {
+    bool is_hex_escape;
+
     if (dstend - dst < 4) {
       upb_bytessink_putbuf(p->output_, p->subc, dstbuf, dst - dstbuf, NULL);
       dst = dstbuf;
     }
 
-    bool is_hex_escape = false;
+    is_hex_escape = false;
     switch (*buf) {
       case '\n': *(dst++) = '\\'; *(dst++) = 'n';  break;
       case '\r': *(dst++) = '\\'; *(dst++) = 'r';  break;
@@ -74,9 +77,9 @@ static int putescaped(upb_textprinter *p, const char *buf, size_t len,
       case '\'': *(dst++) = '\\'; *(dst++) = '\''; break;
       case '\\': *(dst++) = '\\'; *(dst++) = '\\'; break;
       default:
-        // Note that if we emit \xNN and the buf character after that is a hex
-        // digit then that digit must be escaped too to prevent it being
-        // interpreted as part of the character code by C.
+        /* Note that if we emit \xNN and the buf character after that is a hex
+         * digit then that digit must be escaped too to prevent it being
+         * interpreted as part of the character code by C. */
         if ((!preserve_utf8 || (uint8_t)*buf < 0x80) &&
             (!isprint(*buf) || (last_hex_escape && isxdigit(*buf)))) {
           sprintf(dst, (use_hex ? "\\x%02x" : "\\%03o"), (uint8_t)*buf);
@@ -88,29 +91,38 @@ static int putescaped(upb_textprinter *p, const char *buf, size_t len,
     }
     last_hex_escape = is_hex_escape;
   }
-  // Flush remaining data.
+  /* Flush remaining data. */
   upb_bytessink_putbuf(p->output_, p->subc, dstbuf, dst - dstbuf, NULL);
   return 0;
 }
 
+#ifdef __GNUC__
+#define va_copy(a, b) __va_copy(a, b)
+#endif
+
 bool putf(upb_textprinter *p, const char *fmt, ...) {
   va_list args;
+  va_list args_copy;
+  char *str;
+  int written;
+  int len;
+  bool ok;
+
   va_start(args, fmt);
 
-  // Run once to get the length of the string.
-  va_list args_copy;
+  /* Run once to get the length of the string. */
   va_copy(args_copy, args);
-  int len = vsnprintf(NULL, 0, fmt, args_copy);
+  len = vsprintf(NULL, fmt, args_copy);
   va_end(args_copy);
 
-  // + 1 for NULL terminator (vsnprintf() requires it even if we don't).
-  char *str = malloc(len + 1);
+  /* + 1 for NULL terminator (vsprintf() requires it even if we don't). */
+  str = malloc(len + 1);
   if (!str) return false;
-  int written = vsnprintf(str, len + 1, fmt, args);
+  written = vsprintf(str, fmt, args);
   va_end(args);
   UPB_ASSERT_VAR(written, written == len);
 
-  bool ok = upb_bytessink_putbuf(p->output_, p->subc, str, len, NULL);
+  ok = upb_bytessink_putbuf(p->output_, p->subc, str, len, NULL);
   free(str);
   return ok;
 }
@@ -119,8 +131,8 @@ bool putf(upb_textprinter *p, const char *fmt, ...) {
 /* handlers *******************************************************************/
 
 static bool textprinter_startmsg(void *c, const void *hd) {
-  UPB_UNUSED(hd);
   upb_textprinter *p = c;
+  UPB_UNUSED(hd);
   if (p->indent_depth_ == 0) {
     upb_bytessink_start(p->output_, 0, &p->subc);
   }
@@ -128,9 +140,9 @@ static bool textprinter_startmsg(void *c, const void *hd) {
 }
 
 static bool textprinter_endmsg(void *c, const void *hd, upb_status *s) {
+  upb_textprinter *p = c;
   UPB_UNUSED(hd);
   UPB_UNUSED(s);
-  upb_textprinter *p = c;
   if (p->indent_depth_ == 0) {
     upb_bytessink_end(p->output_);
   }
@@ -167,14 +179,14 @@ err:
 
 TYPE(int32,  int32_t,  "%" PRId32)
 TYPE(int64,  int64_t,  "%" PRId64)
-TYPE(uint32, uint32_t, "%" PRIu32);
+TYPE(uint32, uint32_t, "%" PRIu32)
 TYPE(uint64, uint64_t, "%" PRIu64)
 TYPE(float,  float,    "%." STRINGIFY_MACROVAL(FLT_DIG) "g")
 TYPE(double, double,   "%." STRINGIFY_MACROVAL(DBL_DIG) "g")
 
 #undef TYPE
 
-// Output a symbolic value from the enum if found, else just print as int32.
+/* Output a symbolic value from the enum if found, else just print as int32. */
 static bool textprinter_putenum(void *closure, const void *handler_data,
                                 int32_t val) {
   upb_textprinter *p = closure;
@@ -194,17 +206,17 @@ static bool textprinter_putenum(void *closure, const void *handler_data,
 
 static void *textprinter_startstr(void *closure, const void *handler_data,
                       size_t size_hint) {
+  upb_textprinter *p = closure;
   const upb_fielddef *f = handler_data;
   UPB_UNUSED(size_hint);
-  upb_textprinter *p = closure;
   indent(p);
   putf(p, "%s: \"", upb_fielddef_name(f));
   return p;
 }
 
 static bool textprinter_endstr(void *closure, const void *handler_data) {
-  UPB_UNUSED(handler_data);
   upb_textprinter *p = closure;
+  UPB_UNUSED(handler_data);
   putf(p, "\"");
   endfield(p);
   return true;
@@ -212,9 +224,9 @@ static bool textprinter_endstr(void *closure, const void *handler_data) {
 
 static size_t textprinter_putstr(void *closure, const void *hd, const char *buf,
                                  size_t len, const upb_bufhandle *handle) {
-  UPB_UNUSED(handle);
   upb_textprinter *p = closure;
   const upb_fielddef *f = hd;
+  UPB_UNUSED(handle);
   CHECK(putescaped(p, buf, len, upb_fielddef_type(f) == UPB_TYPE_STRING));
   return len;
 err:
@@ -233,8 +245,8 @@ err:
 }
 
 static bool textprinter_endsubmsg(void *closure, const void *handler_data) {
-  UPB_UNUSED(handler_data);
   upb_textprinter *p = closure;
+  UPB_UNUSED(handler_data);
   p->indent_depth_--;
   CHECK(indent(p));
   upb_bytessink_putbuf(p->output_, p->subc, "}", 1, NULL);
@@ -245,13 +257,13 @@ err:
 }
 
 static void onmreg(const void *c, upb_handlers *h) {
-  UPB_UNUSED(c);
   const upb_msgdef *m = upb_handlers_msgdef(h);
+  upb_msg_field_iter i;
+  UPB_UNUSED(c);
 
   upb_handlers_setstartmsg(h, textprinter_startmsg, NULL);
   upb_handlers_setendmsg(h, textprinter_endmsg, NULL);
 
-  upb_msg_field_iter i;
   for(upb_msg_field_begin(&i, m);
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {