+/* Expansion registration --------------------------------------------------- */
+
+static int mx__register(unsigned flags,
+ const char *name,
+ int min,
+ int max,
+ char **args,
+ void (*callback)(),
+ const struct mx_node *definition) {
+ struct expansion e[1];
+
+ if(!expansions)
+ expansions = hash_new(sizeof(struct expansion));
+ e->min = min;
+ e->max = max;
+ e->flags = flags;
+ e->args = args;
+ e->callback = callback;
+ e->definition = definition;
+ return hash_add(expansions, name, &e, HASH_INSERT_OR_REPLACE);
+}
+
+/** @brief Register a simple expansion rule
+ * @param name Name
+ * @param min Minimum number of arguments
+ * @param max Maximum number of arguments
+ * @param callback Callback to write output
+ */
+void mx_register(const char *name,
+ int min,
+ int max,
+ mx_simple_callback *callback) {
+ mx__register(EXP_SIMPLE, name, min, max, 0, (void (*)())callback, 0);
+}
+
+/** @brief Register a magic expansion rule
+ * @param name Name
+ * @param min Minimum number of arguments
+ * @param max Maximum number of arguments
+ * @param callback Callback to write output
+ */
+void mx_register_magic(const char *name,
+ int min,
+ int max,
+ mx_magic_callback *callback) {
+ mx__register(EXP_MAGIC, name, min, max, 0, (void (*)())callback, 0);
+}
+
+/** @brief Register a macro
+ * @param name Name
+ * @param nargs Number of arguments
+ * @param args Argument names
+ * @param definition Macro definition
+ * @return 0 on success, negative on error
+ */
+int mx_register_macro(const char *name,
+ int nargs,
+ char **args,
+ const struct mx_node *definition) {
+ if(mx__register(EXP_MACRO, name, nargs, nargs, args, 0/*callback*/,
+ definition)) {
+#if 0
+ /* This locates the error to the definition, which may be a line or two
+ * beyond the @define command itself. The backtrace generated by
+ * mx_expand() may help more. */
+ error(0, "%s:%d: duplicate definition of '%s'",
+ definition->filename, definition->line, name);
+#endif
+ return -2;
+ }
+ return 0;
+}
+
+/* Expansion ---------------------------------------------------------------- */
+
+/** @brief Expand a template
+ * @param m Where to start
+ * @param output Where to send output
+ * @param u User data
+ * @return 0 on success, non-0 on error
+ *
+ * Interpretation of return values:
+ * - 0 means success
+ * - -1 means an error writing to the sink.
+ * - other negative values mean errors generated from with the macro
+ * expansion system
+ * - positive values are reserved for the application
+ *
+ * If any callback returns non-zero then that value is returned, abandoning
+ * further expansion.
+ */
+int mx_expand(const struct mx_node *m,
+ struct sink *output,
+ void *u) {
+ const struct expansion *e;
+ int rc;
+
+ if(!m)
+ return 0;
+ switch(m->type) {
+ case MX_TEXT:
+ if(sink_writes(output, m->text) < 0)
+ return -1;
+ break;
+ case MX_EXPANSION:
+ rc = 0;
+ if(!(e = hash_find(expansions, m->name))) {
+ error(0, "%s:%d: unknown expansion name '%s'",
+ m->filename, m->line, m->name);
+ if(sink_printf(output, "[['%s' unknown]]", m->name) < 0)
+ return -1;
+ } else if(m->nargs < e->min) {
+ error(0, "%s:%d: expansion '%s' requires %d args, only %d given",
+ m->filename, m->line, m->name, e->min, m->nargs);
+ if(sink_printf(output, "[['%s' too few args]]", m->name) < 0)
+ return -1;
+ } else if(m->nargs > e->max) {
+ error(0, "%s:%d: expansion '%s' takes at most %d args, but %d given",
+ m->filename, m->line, m->name, e->max, m->nargs);
+ if(sink_printf(output, "[['%s' too many args]]", m->name) < 0)
+ return -1;
+ } else switch(e->flags & EXP_TYPE_MASK) {
+ case EXP_MAGIC: {
+ /* Magic callbacks we can call directly */
+ rc = ((mx_magic_callback *)e->callback)(m->nargs,
+ m->args,
+ output,
+ u);
+ break;
+ }
+ case EXP_SIMPLE: {
+ /* For simple callbacks we expand their arguments for them. */
+ char **args = xcalloc(1 + m->nargs, sizeof (char *)), *argname;
+ int n;
+
+ for(n = 0; n < m->nargs; ++n) {
+ /* Argument numbers are at least clear from looking at the text;
+ * adding names as well would be nice. TODO */
+ byte_xasprintf(&argname, "argument #%d", n);
+ if((rc = mx_expandstr(m->args[n], &args[n], u, argname)))
+ break;
+ }
+ if(!rc) {
+ args[n] = NULL;
+ rc = ((mx_simple_callback *)e->callback)(m->nargs,
+ args,
+ output,
+ u);
+ }
+ break;
+ }
+ case EXP_MACRO: {
+ /* Macros we expand by rewriting their definition with argument values
+ * substituted and then expanding that. */
+ rc = mx__expand_macro(e, m, output, u);
+ break;
+ }
+ default:
+ assert(!"impossible EXP_TYPE_MASK value");
+ }
+ if(rc) {
+ /* For non-IO errors we generate some backtrace */
+ if(rc != -1)
+ error(0, " ...in @%s at %s:%d",
+ m->name, m->filename, m->line);
+ return rc;
+ }
+ break;
+ default:
+ assert(!"invalid m->type");
+ }
+ return mx_expand(m->next, output, u);
+}
+
+/** @brief Expand a template storing the result in a string
+ * @param m Where to start
+ * @param sp Where to store string
+ * @param u User data
+ * @param what Token for backtrace, or NULL
+ * @return 0 on success, non-0 on error
+ *
+ * Same return conventions as mx_expand(). This wrapper is slightly more
+ * convenient to use from 'magic' expansions.
+ */
+int mx_expandstr(const struct mx_node *m,
+ char **sp,
+ void *u,
+ const char *what) {
+ struct dynstr d[1];
+ int rc;
+
+ dynstr_init(d);
+ if(!(rc = mx_expand(m, sink_dynstr(d), u))) {
+ dynstr_terminate(d);
+ *sp = d->vec;
+ } else
+ *sp = 0;
+ if(rc && rc != -1 && what)
+ error(0, " ...in %s at %s:%d", what, m->filename, m->line);
+ return rc;
+}
+
+/** @brief Expand a template file
+ * @param path Filename
+ * @param output Where to send output
+ * @param u User data
+ * @return 0 on success, non-0 on error
+ *
+ * Same return conventions as mx_expand().
+ */
+int mx_expand_file(const char *path,
+ struct sink *output,
+ void *u) {
+ int fd, n, rc;
+ struct stat sb;
+ char *b;
+ off_t sofar;
+ const struct mx_node *m;
+
+ if((fd = open(path, O_RDONLY)) < 0)
+ fatal(errno, "error opening %s", path);
+ if(fstat(fd, &sb) < 0)
+ fatal(errno, "error statting %s", path);
+ if(!S_ISREG(sb.st_mode))
+ fatal(0, "%s: not a regular file", path);
+ sofar = 0;
+ b = xmalloc_noptr(sb.st_size);
+ while(sofar < sb.st_size) {
+ n = read(fd, b + sofar, sb.st_size - sofar);
+ if(n > 0)
+ sofar += n;
+ else if(n == 0)
+ fatal(0, "unexpected EOF reading %s", path);
+ else if(errno != EINTR)
+ fatal(errno, "error reading %s", path);
+ }
+ xclose(fd);
+ m = mx_parse(path, 1, b, b + sb.st_size);
+ rc = mx_expand(m, output, u);
+ if(rc && rc != -1)
+ /* Mention inclusion in backtrace */
+ error(0, " ...in inclusion of file '%s'", path);
+ return rc;
+}
+
+/* Macros ------------------------------------------------------------------- */
+
+/** @brief Rewrite a parse tree substituting sub-expansions
+ * @param m Parse tree to rewrite (from macro definition)
+ * @param ... Name/value pairs to rewrite
+ * @return Rewritten parse tree
+ *
+ * The name/value pair list consists of pairs of strings and is terminated by
+ * (char *)0. Names and values are both copied so need not survive the call.
+ */
+const struct mx_node *mx_rewritel(const struct mx_node *m,
+ ...) {
+ va_list ap;
+ hash *h = hash_new(sizeof (struct mx_node *));
+ const char *n, *v;
+ struct mx_node *e;
+
+ va_start(ap, m);
+ while((n = va_arg(ap, const char *))) {
+ v = va_arg(ap, const char *);
+ e = xmalloc(sizeof *e);
+ e->next = 0;
+ e->filename = m->filename;
+ e->line = m->line;
+ e->type = MX_TEXT;
+ e->text = xstrdup(v);
+ hash_add(h, n, &e, HASH_INSERT);
+ /* hash_add() copies n */
+ }
+ return mx_rewrite(m, h);
+}
+
+/** @brief Rewrite a parse tree substituting in macro arguments
+ * @param definition Parse tree to rewrite (from macro definition)
+ * @param h Hash mapping argument names to argument values
+ * @return Rewritten parse tree
+ */
+const struct mx_node *mx_rewrite(const struct mx_node *definition,
+ hash *h) {
+ const struct mx_node *head = 0, **tailp = &head, *argvalue, *m, *mm, **ap;
+ struct mx_node *nm;
+ int n;
+
+ for(m = definition; m; m = m->next) {
+ switch(m->type) {
+ case MX_TEXT:
+ nm = xmalloc(sizeof *nm);
+ *nm = *m; /* Dumb copy of text node fields */
+ nm->next = 0; /* Maintain list structure */
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ break;
+ case MX_EXPANSION:
+ if(m->nargs == 0
+ && (ap = hash_find(h, m->name))) {
+ /* This expansion has no arguments and its name matches one of the
+ * macro arguments. (Even if it's a valid expansion name we override
+ * it.) We insert its value at this point. We do NOT recursively
+ * rewrite the argument's value - it is outside the lexical scope of
+ * the argument name.
+ *
+ * We need to recreate the list structure but a shallow copy will
+ * suffice here.
+ */
+ argvalue = *ap;
+ for(mm = argvalue; mm; mm = mm->next) {
+ nm = xmalloc(sizeof *nm);
+ *nm = *mm;
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ } else {
+ /* This is some other expansion. We recursively rewrite its argument
+ * values according to h. */
+ nm = xmalloc(sizeof *nm);
+ *nm = *m;
+ nm->args = xcalloc(nm->nargs, sizeof (struct mx_node *));
+ for(n = 0; n < nm->nargs; ++n)
+ nm->args[n] = mx_rewrite(m->args[n], h);
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ break;
+ default:
+ assert(!"invalid m->type");
+ }
+ }
+ *tailp = 0; /* Mark end of list */
+ return head;
+}
+
+/** @brief Expand a macro
+ * @param e Macro definition
+ * @param m Macro expansion
+ * @param output Where to send output
+ * @param u User data
+ * @return 0 on success, non-0 on error
+ */
+static int mx__expand_macro(const struct expansion *e,
+ const struct mx_node *m,
+ struct sink *output,
+ void *u) {
+ hash *h = hash_new(sizeof (struct mx_node *));
+ int n;
+
+ /* We store the macro arguments in a hash. Currently there is no check for
+ * duplicate argument names (and this would be the wrong place for it
+ * anyway); if you do that you just lose in some undefined way. */
+ for(n = 0; n < m->nargs; ++n)
+ hash_add(h, e->args[n], &m->args[n], HASH_INSERT);
+ /* Generate a rewritten parse tree */
+ m = mx_rewrite(e->definition, h);
+ /* Expand the result */
+ return mx_expand(m, output, u);
+ /* mx_expand() will update the backtrace */
+}
+
~mdw / disorder / blobdiff