libcdecl: reduce snprintf reliance for error reporting.

[cdecl99.git] / src / error.c

diff --git a/src/error.c b/src/error.c
index 8b9f04e55cd4f0de103283d6f707362366ca4483..758f58e63c50d4159195b08189c10cd6467e06c2 100644 (file)
--- a/src/error.c
+++ b/src/error.c
@@ -19,9 +19,7 @@
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <assert.h>
-#include <stdarg.h>
 
 #include "cdecl.h"
 #include "cdecl-internal.h"
@@ -29,8 +27,7 @@
 #include <glthread/lock.h>
 #include <glthread/tls.h>
 
-gl_once_define(static, tls_initialized);
-static gl_tls_key_t tls_key;
+#include "errmsg.h"
 
 struct err_state {
        struct cdecl_error err;
@@ -40,6 +37,7 @@ struct err_state {
 
 /* This pre-initialized error is reserved for dire out-of-memory conditions. */
 static struct cdecl_error err_no_mem;
+static gl_tls_key_t tls_key;
 
 static void free_err(void *err)
 {
@@ -49,10 +47,29 @@ static void free_err(void *err)
        free(err);
 }
 
-static void initialize(void)
+static void set_err(unsigned code, struct cdecl_error *err)
 {
-       cdecl__init_i18n();
-       err_no_mem.str = _("failed to allocate memory");
+       static const char errmsgs[] = STRTAB_INITIALIZER;
+
+       switch (code) {
+       case CDECL__ENOMEM:
+               err->code = CDECL_ENOMEM;
+               break;
+       default:
+               err->code = CDECL_ENOPARSE;
+               break;
+       }
+
+       err->str = _(&errmsgs[code]);
+}
+
+static void initialize_cb(void)
+{
+#if ENABLE_NLS
+       bindtextdomain(PACKAGE, LOCALEDIR);
+       bindtextdomain("bison-runtime", BISON_LOCALEDIR);
+#endif
+       set_err(CDECL__ENOMEM, &err_no_mem);
        gl_tls_key_init(tls_key, free_err);
 }
 
@@ -80,7 +97,8 @@ static struct err_state *get_err_state(void)
 {
        void *state;
 
-       gl_once(tls_initialized, initialize);
+       gl_once_define(static, tls_initialized)
+       gl_once(tls_initialized, initialize_cb);
 
        state = gl_tls_get(tls_key);
        if (state == &err_no_mem)
@@ -90,36 +108,80 @@ static struct err_state *get_err_state(void)
        return state;
 }
 
+
+#if ENABLE_NLS
 /*
- * cdecl__err(CDECL_ENOMEM);
- * cdecl__err(code, fmt, ...);
- *
- * Sets the library error to code, with a printf-style error string.
+ * Initialize gettext indirectly via get_err_state.
  */
-void cdecl__err(unsigned code, ...)
+void cdecl__init_i18n(void)
+{
+       get_err_state();
+}
+#endif
+
+/*
+ * Set the library error to one of the preset messages defined in errmsg.h
+ * (CDECL__Exxx).
+ */
+void cdecl__errmsg(unsigned msg)
 {
-       const char *fmt;
        struct err_state *state;
-       int rc, try = 0;
-       va_list ap;
 
        state = get_err_state();
        if (!state)
                return;
 
-       if (code == CDECL_ENOMEM) {
-               state->err.code = code;
-               state->err.str = err_no_mem.str;
+       set_err(msg, &state->err);
+}
+
+/*
+ * In the NLS-disabled case, all format strings are of the form
+ *
+ *   "blah blah %s"
+ *
+ * so we exploit this to implement a simple snprintf workalike using the
+ * libcdecl output helpers directly.
+ *
+ * In the NLS-enabled case, we have to use snprintf as format strings may
+ * be translated.  GNU libintl ensures a suitable version is available.
+ */
+static size_t
+fmt_err(struct err_state *state, const char *fmt, const char *arg)
+{
+#if ENABLE_NLS
+       snprintf(state->str, state->nstr, fmt, arg);
+       return strlen(fmt) + strlen(arg);
+#else
+       struct output_state dst = { state->str, state->nstr };
+       size_t rc;
+
+       rc = cdecl__strlcpy(dst.dst, fmt, dst.dstlen);
+       cdecl__advance(&dst, rc-2);
+       cdecl__emit(&dst, arg);
+
+       return dst.accum;
+#endif
+}
+
+/*
+ * Sets the library error to code; fmt is a printf-style string that may use
+ * up to one %s directive, to refer to arg.
+ */
+void cdecl__err(unsigned code, const char *fmt, const char *arg)
+{
+       struct err_state *state;
+       unsigned try = 0;
+       size_t rc;
+
+       state = get_err_state();
+       if (!state)
                return;
-       }
-retry:
-       va_start(ap, code);
-       fmt = va_arg(ap, const char *);
-       rc = vsnprintf(state->str, state->nstr, fmt, ap);
-       va_end(ap);
 
-       if (rc > 0 && rc >= state->nstr) {
+retry:
+       rc = fmt_err(state, fmt, arg);
+       if (rc >= state->nstr) {
                assert(try++ == 0 && rc < SIZE_MAX / 4);
+
                state = alloc_err_state(state, (size_t)(rc+1u) * 3 / 2);
                if (!state)
                        return;