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[PATCH 11/17] Add JSON implementation
- From: David Malcolm <dmalcolm at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: David Malcolm <dmalcolm at redhat dot com>
- Date: Mon, 24 Jul 2017 16:05:08 -0400
- Subject: [PATCH 11/17] Add JSON implementation
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This patch is the first part of the Language Server Protocol
server proof-of-concept.
It adds support to gcc for reading and writing JSON,
based on DOM-like trees of "json::value" instances.
gcc/ChangeLog:
* Makefile.in (OBJS): Add json.o.
* json.c: New file.
* json.h: New file.
* selftest-run-tests.c (selftest::run_tests): Call json_c_tests.
* selftest.h (selftest::json_c_tests): New decl.
---
gcc/Makefile.in | 1 +
gcc/json.c | 1914 ++++++++++++++++++++++++++++++++++++++++++++++
gcc/json.h | 214 ++++++
gcc/selftest-run-tests.c | 1 +
gcc/selftest.h | 1 +
5 files changed, 2131 insertions(+)
create mode 100644 gcc/json.c
create mode 100644 gcc/json.h
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 519ada0..77ecbd6 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1369,6 +1369,7 @@ OBJS = \
ira-color.o \
ira-emit.o \
ira-lives.o \
+ json.o \
jump.o \
langhooks.o \
lcm.o \
diff --git a/gcc/json.c b/gcc/json.c
new file mode 100644
index 0000000..9f8b456
--- /dev/null
+++ b/gcc/json.c
@@ -0,0 +1,1914 @@
+/* JSON parsing
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "json.h"
+#include "pretty-print.h"
+#include "math.h"
+#include "selftest.h"
+
+using namespace json;
+
+/* class json::value. */
+
+/* Generate a char * for this json::value tree.
+ The returned value must be freed by the caller. */
+
+char *
+value::to_str () const
+{
+ pretty_printer pp;
+ print (&pp);
+ return xstrdup (pp_formatted_text (&pp));
+}
+
+/* Dump this json::value tree to OUTF.
+ No formatting is done. There are no guarantees about the order
+ in which the key/value pairs of json::objects are printed. */
+
+void
+value::dump (FILE *outf) const
+{
+ pretty_printer pp;
+ pp_buffer (&pp)->stream = outf;
+ print (&pp);
+ pp_flush (&pp);
+}
+
+/* If this json::value is a json::object, return it,
+ otherwise return NULL. */
+
+const object *
+value::as_object () const
+{
+ if (get_kind () != JSON_OBJECT)
+ return NULL;
+ return static_cast <const object *> (this);
+}
+
+/* If this json::value is a json::array, return it,
+ otherwise return NULL. */
+
+const array *
+value::as_array () const
+{
+ if (get_kind () != JSON_ARRAY)
+ return NULL;
+ return static_cast <const array *> (this);
+}
+
+/* If this json::value is a json::number, return it,
+ otherwise return NULL. */
+
+const number *
+value::as_number () const
+{
+ if (get_kind () != JSON_NUMBER)
+ return NULL;
+ return static_cast <const number *> (this);
+}
+
+/* If this json::value is a json::string, return it,
+ otherwise return NULL. */
+
+const string *
+value::as_string () const
+{
+ if (get_kind () != JSON_STRING)
+ return NULL;
+ return static_cast <const string *> (this);
+}
+
+/* Attempt to get the value of a key/value pair from this value
+ as if THIS value were an object.
+
+ If THIS is not a json::object, return write an error message to OUT_ERR
+ (which must be freed by the caller) and return false.
+
+ Otherwise write the value ptr (possibly NULL) to OUT_VALUE and
+ return true. */
+
+bool
+value::get_optional_value_by_key (const char *name, const value *&out_value,
+ char *&out_err) const
+{
+ const json::object *obj = as_object ();
+ if (!obj)
+ {
+ out_err = xstrdup ("not an object");
+ return false;
+ }
+ out_value = obj->get (name);
+ return true;
+}
+
+/* Attempt to get a string value of a key/value pair from this value
+ as if THIS value were an object.
+
+ If THIS is a json::object, and KEY is either not present, is a string,
+ or is the "null" JSON literal, then return true, and write to OUT_VALUE.
+ If a string, then the ptr is written to OUT_VALUE, otherwise NULL
+ is written to OUT_VALUE.
+
+ If THIS is not a json::object, or KEY is not a string/"null",
+ return false and write an error message to OUT_ERR
+ (which must be freed by the caller). */
+
+bool
+value::get_optional_string_by_key (const char *name, const char *&out_value,
+ char *&out_err) const
+{
+ const json::value *v;
+ if (!get_optional_value_by_key (name, v, out_err))
+ return false;
+ if (v && v->get_kind () != JSON_NULL)
+ {
+ const json::string *s = v->as_string ();
+ if (!s)
+ {
+ out_err = xasprintf ("not a string: \"%s\"", name);
+ return false;
+ }
+ out_value = s->get_string ();
+ return true;
+ }
+ else
+ {
+ out_value = NULL;
+ return true;
+ }
+}
+
+/* Attempt to get lookup the value of a key/value pair from this value
+ as if this value were an object.
+
+ To succeed, THIS must be a json::object, and it must have a key named
+ NAME.
+
+ On success, return true and write the value to OUT_VALUE.
+ On failure, return false and write an error message to OUT_ERR
+ (which must be freed by the caller). */
+
+bool
+value::get_value_by_key (const char *name, const value *&out_value,
+ char *&out_err) const
+{
+ const json::object *obj = as_object ();
+ if (!obj)
+ {
+ out_err = xstrdup ("not an object");
+ return false;
+ }
+ const json::value *v = obj->get (name);
+ if (!v)
+ {
+ out_err = xasprintf ("missing attribute: \"%s\"", name);
+ return false;
+ }
+ out_value = v;
+ return true;
+}
+
+/* As value::get_value_by_key, but the value must be a number;
+ if successful, write it as an int to OUT_VALUE. */
+
+bool
+value::get_int_by_key (const char *name, int &out_value, char *&out_err) const
+{
+ const json::value *v;
+ if (!get_value_by_key (name, v, out_err))
+ return false;
+ const json::number *n = v->as_number ();
+ if (!n)
+ {
+ out_err = xasprintf ("not a number: \"%s\"", name);
+ return false;
+ }
+ out_value = n->get ();
+ return true;
+}
+
+/* As value::get_value_by_key, but the value must be a string;
+ if successful, write it as const char * to OUT_VALUE. */
+
+bool
+value::get_string_by_key (const char *name, const char *&out_value,
+ char *&out_err) const
+{
+ const json::value *v;
+ if (!get_value_by_key (name, v, out_err))
+ return false;
+ const json::string *s = v->as_string ();
+ if (!s)
+ {
+ out_err = xasprintf ("not a string: \"%s\"", name);
+ return false;
+ }
+ out_value = s->get_string ();
+ return true;
+}
+
+/* As value::get_value_by_key, but the value must be an array;
+ if successful, write it as a json::array * to OUT_VALUE. */
+
+bool
+value::get_array_by_key (const char *name, const array *&out_value,
+ char *&out_err) const
+{
+ const json::value *v;
+ if (!get_value_by_key (name, v, out_err))
+ return false;
+ const json::array *arr = v->as_array ();
+ if (!arr)
+ {
+ out_err = xasprintf ("not an array: \"%s\"", name);
+ return false;
+ }
+ out_value = arr;
+ return true;
+}
+
+/* class json::object, a subclass of json::value, representing
+ an unordered collection of key/value pairs. */
+
+/* json:object's dtor. */
+
+object::~object ()
+{
+ for (map_t::iterator it = m_map.begin (); it != m_map.end (); ++it)
+ {
+ free (const_cast <char *>((*it).first));
+ delete ((*it).second);
+ }
+}
+
+/* Implementation of json::value::print for json::object. */
+
+void
+object::print (pretty_printer *pp) const
+{
+ /* Note that the order is not guaranteed. */
+ pp_character (pp, '{');
+ for (map_t::iterator it = m_map.begin (); it != m_map.end (); ++it)
+ {
+ if (it != m_map.begin ())
+ pp_string (pp, ", ");
+ const char *key = const_cast <char *>((*it).first);
+ value *value = (*it).second;
+ pp_printf (pp, "\"%s\": ", key); // FIXME: escaping?
+ value->print (pp);
+ }
+ pp_character (pp, '}');
+}
+
+/* Implementation of json::value::clone for json::object. */
+
+value *
+object::clone () const
+{
+ object *other = new object ();
+ for (map_t::iterator it = m_map.begin (); it != m_map.end (); ++it)
+ {
+ const char *key = const_cast <char *>((*it).first);
+ value *value = (*it).second;
+ other->set (key, value->clone ());
+ }
+ return other;
+}
+
+/* Get the json::value * for KEY, or NULL if the key is not present. */
+
+value *
+object::get (const char *key) const
+{
+ value **slot = const_cast <object*> (this)->m_map.get (key);
+ if (slot)
+ return *slot;
+ return NULL;
+}
+
+/* As object::get (KEY), but return NULL if the value of the key
+ is the "null" JSON literal. */
+
+value *
+object::get_if_nonnull (const char *key) const
+{
+ value *result = get (key);
+ if (!result)
+ return NULL;
+ if (result->get_kind () == JSON_NULL)
+ return NULL;
+ return result;
+}
+
+/* Set the json::value * for KEY, taking ownership of VALUE
+ (and taking a copy of KEY if necessary). */
+
+void
+object::set (const char *key, value *v)
+{
+ value **ptr = m_map.get (key);
+ if (ptr)
+ {
+ /* If the key is already present, delete the existing value
+ and overwrite it. */
+ delete *ptr;
+ *ptr = v;
+ }
+ else
+ /* If the key wasn't already present, take a copy of the key,
+ and store the value. */
+ m_map.put (xstrdup (key), v);
+}
+
+/* class json::array, a subclass of json::value, representing
+ an ordered collection of values. */
+
+/* json::array's dtor. */
+
+array::~array ()
+{
+ unsigned i;
+ value *v;
+ FOR_EACH_VEC_ELT (m_elements, i, v)
+ delete v;
+}
+
+/* Implementation of json::value::print for json::array. */
+
+void
+array::print (pretty_printer *pp) const
+{
+ pp_character (pp, '[');
+ unsigned i;
+ value *v;
+ FOR_EACH_VEC_ELT (m_elements, i, v)
+ {
+ if (i)
+ pp_string (pp, ", ");
+ v->print (pp);
+ }
+ pp_character (pp, ']');
+}
+
+/* Implementation of json::value::clone for json::array. */
+
+value *
+array::clone () const
+{
+ array *other = new array ();
+ unsigned i;
+ value *v;
+ FOR_EACH_VEC_ELT (m_elements, i, v)
+ other->append (v->clone ());
+ return other;
+}
+
+/* class json::number, a subclass of json::value, wrapping a double. */
+
+/* Implementation of json::value::print for json::number. */
+
+void
+number::print (pretty_printer *pp) const
+{
+ char tmp[1024];
+ snprintf (tmp, sizeof (tmp), "%g", m_value);
+ pp_string (pp, tmp);
+}
+
+/* Implementation of json::value::clone for json::number. */
+
+value *
+number::clone () const
+{
+ return new number (m_value);
+}
+
+/* class json::string, a subclass of json::value. */
+
+void
+string::print (pretty_printer *pp) const
+{
+ pp_character (pp, '"');
+ for (const char *ptr = m_utf8; *ptr; ptr++)
+ {
+ char ch = *ptr;
+ switch (ch)
+ {
+ case '"':
+ pp_string (pp, "\\\"");
+ break;
+ case '\\':
+ pp_string (pp, "\\n");
+ break;
+ case '\b':
+ pp_string (pp, "\\b");
+ break;
+ case '\f':
+ pp_string (pp, "\\f");
+ break;
+ case '\n':
+ pp_string (pp, "\\n");
+ break;
+ case '\r':
+ pp_string (pp, "\\r");
+ break;
+ case '\t':
+ pp_string (pp, "\\t");
+ break;
+
+ default:
+ pp_character (pp, ch);
+ }
+ }
+ pp_character (pp, '"');
+}
+
+/* Implementation of json::value::clone for json::string. */
+
+value *
+string::clone () const
+{
+ return new string (m_utf8);
+}
+
+/* class json::literal, a subclass of json::value. */
+
+/* Implementation of json::value::print for json::literal. */
+
+void
+literal::print (pretty_printer *pp) const
+{
+ switch (m_kind)
+ {
+ case JSON_TRUE:
+ pp_string (pp, "true");
+ break;
+ case JSON_FALSE:
+ pp_string (pp, "false");
+ break;
+ case JSON_NULL:
+ pp_string (pp, "null");
+ break;
+ default:
+ gcc_unreachable ();
+ }
+}
+
+/* Implementation of json::value::clone for json::literal. */
+
+value *
+literal::clone () const
+{
+ return new literal (m_kind);
+}
+
+
+/* Declarations relating to parsing JSON, all within an
+ anonymous namespace. */
+
+namespace {
+
+/* A typedef representing a single unicode character. */
+
+typedef unsigned unichar;
+
+/* An enum for discriminating different kinds of JSON token. */
+
+enum token_id
+{
+ TOK_ERROR,
+
+ TOK_EOF,
+
+ /* Punctuation. */
+ TOK_OPEN_SQUARE,
+ TOK_OPEN_CURLY,
+ TOK_CLOSE_SQUARE,
+ TOK_CLOSE_CURLY,
+ TOK_COLON,
+ TOK_COMMA,
+
+ /* Literal names. */
+ TOK_TRUE,
+ TOK_FALSE,
+ TOK_NULL,
+
+ TOK_STRING,
+ TOK_NUMBER
+};
+
+/* Human-readable descriptions of enum token_id. */
+
+static const char *token_id_name[] = {
+ "error",
+ "EOF",
+ "'['",
+ "'{'",
+ "']'",
+ "'}'",
+ "':'",
+ "','",
+ "'true'",
+ "'false'",
+ "'null'",
+ "string",
+ "number"
+};
+
+/* Tokens within the JSON lexer. */
+
+struct token
+{
+ /* The kind of token. */
+ enum token_id id;
+
+ /* The location of this token within the unicode
+ character stream. */
+ int index;
+
+ union
+ {
+ /* Value for TOK_ERROR and TOK_STRING. */
+ char *string;
+
+ /* Value for TOK_NUMBER. */
+ double number;
+ } u;
+};
+
+/* A class for lexing JSON. */
+
+class lexer
+{
+ public:
+ lexer ();
+ ~lexer ();
+ bool add_utf8 (size_t length, const char *utf8_buf, char **err_out);
+
+ const token *peek ();
+ void consume ();
+
+ private:
+ bool get_char (unichar &out);
+ void unget_char ();
+ static void dump_token (FILE *outf, const token *tok);
+ void lex_token (token *out);
+ void lex_string (token *out);
+ void lex_number (token *out, unichar first_char);
+ bool rest_of_literal (const char *suffix);
+
+ private:
+ auto_vec<unichar> m_buffer;
+ int m_next_char_idx;
+
+ static const int MAX_TOKENS = 1;
+ token m_next_tokens[MAX_TOKENS];
+ int m_num_next_tokens;
+};
+
+/* A class for parsing JSON. */
+
+class parser
+{
+ public:
+ parser (char **err_out);
+ bool add_utf8 (size_t length, const char *utf8_buf, char **err_out);
+ value *parse_value (int depth);
+ object *parse_object (int depth);
+ array *parse_array (int depth);
+
+ bool seen_error_p () const { return *m_err_out; }
+ void require_eof ();
+
+ private:
+ void require (enum token_id tok_id);
+ void error_at (int, const char *, ...) ATTRIBUTE_PRINTF_3;
+
+ private:
+ lexer m_lexer;
+ char **m_err_out;
+};
+
+} // anonymous namespace for parsing implementation
+
+/* Parser implementation. */
+
+/* lexer's ctor. */
+
+lexer::lexer ()
+: m_buffer (), m_next_char_idx (0), m_num_next_tokens (0)
+{
+}
+
+/* lexer's dtor. */
+
+lexer::~lexer ()
+{
+ while (m_num_next_tokens > 0)
+ consume ();
+}
+
+/* Peek the next token. */
+
+const token *
+lexer::peek ()
+{
+ if (m_num_next_tokens == 0)
+ {
+ lex_token (&m_next_tokens[0]);
+ m_num_next_tokens++;
+ }
+ return &m_next_tokens[0];
+}
+
+/* Consume the next token. */
+
+void
+lexer::consume ()
+{
+ if (m_num_next_tokens == 0)
+ peek ();
+
+ gcc_assert (m_num_next_tokens > 0);
+ gcc_assert (m_num_next_tokens <= MAX_TOKENS);
+
+ if (0)
+ {
+ fprintf (stderr, "consuming token: ");
+ dump_token (stderr, &m_next_tokens[0]);
+ fprintf (stderr, "\n");
+ }
+
+ if (m_next_tokens[0].id == TOK_ERROR
+ || m_next_tokens[0].id == TOK_STRING)
+ free (m_next_tokens[0].u.string);
+
+ m_num_next_tokens--;
+ memmove (&m_next_tokens[0], &m_next_tokens[1],
+ sizeof (token) * m_num_next_tokens);
+}
+
+/* Add LENGTH bytes of UTF-8 encoded text from UTF8_BUF to this lexer's
+ buffer. */
+
+bool
+lexer::add_utf8 (size_t length, const char *utf8_buf, char **err_out)
+{
+ /* FIXME: adapted from charset.c:one_utf8_to_cppchar. */
+ static const uchar masks[6] = { 0x7F, 0x1F, 0x0F, 0x07, 0x03, 0x01 };
+ static const uchar patns[6] = { 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
+
+ const uchar *inbuf = (const unsigned char *) (utf8_buf);
+ const uchar **inbufp = &inbuf;
+ size_t *inbytesleftp = &length;
+
+ while (length > 0)
+ {
+ unichar c;
+ const uchar *inbuf = *inbufp;
+ size_t nbytes, i;
+
+ c = *inbuf;
+ if (c < 0x80)
+ {
+ m_buffer.safe_push (c);
+ *inbytesleftp -= 1;
+ *inbufp += 1;
+ continue;
+ }
+
+ /* The number of leading 1-bits in the first byte indicates how many
+ bytes follow. */
+ for (nbytes = 2; nbytes < 7; nbytes++)
+ if ((c & ~masks[nbytes-1]) == patns[nbytes-1])
+ goto found;
+ *err_out = xstrdup ("ill-formed UTF-8 sequence");
+ return false;
+ found:
+
+ if (*inbytesleftp < nbytes)
+ {
+ *err_out = xstrdup ("ill-formed UTF-8 sequence");
+ return false;
+ }
+
+ c = (c & masks[nbytes-1]);
+ inbuf++;
+ for (i = 1; i < nbytes; i++)
+ {
+ unichar n = *inbuf++;
+ if ((n & 0xC0) != 0x80)
+ {
+ *err_out = xstrdup ("ill-formed UTF-8 sequence");
+ return false;
+ }
+ c = ((c << 6) + (n & 0x3F));
+ }
+
+ /* Make sure the shortest possible encoding was used. */
+ if (( c <= 0x7F && nbytes > 1)
+ || (c <= 0x7FF && nbytes > 2)
+ || (c <= 0xFFFF && nbytes > 3)
+ || (c <= 0x1FFFFF && nbytes > 4)
+ || (c <= 0x3FFFFFF && nbytes > 5))
+ {
+ *err_out = xstrdup ("ill-formed UTF-8:"
+ " shortest possible encoding not used");
+ return false;
+ }
+
+ /* Make sure the character is valid. */
+ if (c > 0x7FFFFFFF || (c >= 0xD800 && c <= 0xDFFF))
+ {
+ *err_out = xstrdup ("ill-formed UTF-8: invalid character");
+ return false;
+ }
+
+ m_buffer.safe_push (c);
+ *inbufp = inbuf;
+ *inbytesleftp -= nbytes;
+ }
+ return true;
+}
+
+/* Attempt to get the next unicode character from this lexer's buffer.
+ If successful, write it to OUT and return true.
+ Otherwise, return false. */
+
+bool
+lexer::get_char (unichar &out)
+{
+ if (m_next_char_idx >= (int)m_buffer.length ())
+ return false;
+
+ out = m_buffer[m_next_char_idx++];
+ return true;
+}
+
+/* FIXME. */
+
+void
+lexer::unget_char ()
+{
+ --m_next_char_idx;
+}
+
+/* Print a textual representation of TOK to OUTF.
+ This is intended for debugging the lexer and parser,
+ rather than for user-facing output. */
+
+void
+lexer::dump_token (FILE *outf, const token *tok)
+{
+ switch (tok->id)
+ {
+ case TOK_ERROR:
+ fprintf (outf, "TOK_ERROR (\"%s\")", tok->u.string);
+ break;
+
+ case TOK_EOF:
+ fprintf (outf, "TOK_EOF");
+ break;
+
+ case TOK_OPEN_SQUARE:
+ fprintf (outf, "TOK_OPEN_SQUARE");
+ break;
+
+ case TOK_OPEN_CURLY:
+ fprintf (outf, "TOK_OPEN_CURLY");
+ break;
+
+ case TOK_CLOSE_SQUARE:
+ fprintf (outf, "TOK_CLOSE_SQUARE");
+ break;
+
+ case TOK_CLOSE_CURLY:
+ fprintf (outf, "TOK_CLOSE_CURLY");
+ break;
+
+ case TOK_COLON:
+ fprintf (outf, "TOK_COLON");
+ break;
+
+ case TOK_COMMA:
+ fprintf (outf, "TOK_COMMA");
+ break;
+
+ case TOK_TRUE:
+ fprintf (outf, "TOK_TRUE");
+ break;
+
+ case TOK_FALSE:
+ fprintf (outf, "TOK_FALSE");
+ break;
+
+ case TOK_NULL:
+ fprintf (outf, "TOK_NULL");
+ break;
+
+ case TOK_STRING:
+ fprintf (outf, "TOK_STRING (\"%s\")", tok->u.string);
+ break;
+
+ case TOK_NUMBER:
+ fprintf (outf, "TOK_NUMBER (%f)", tok->u.number);
+ break;
+
+ default:
+ gcc_unreachable ();
+ break;
+ }
+}
+
+/* Attempt to lex the input buffer, writing the next token to OUT.
+ On errors, TOK_ERROR (or TOK_EOF) is written to OUT. */
+
+void
+lexer::lex_token (token *out)
+{
+ /* Skip to next non-whitespace char. */
+ unichar next_char;
+ while (1)
+ {
+ out->index = m_next_char_idx;
+ if (!get_char (next_char))
+ {
+ out->id = TOK_EOF;
+ return;
+ }
+ if (next_char != ' '
+ && next_char != '\t'
+ && next_char != '\n'
+ && next_char != '\r')
+ break;
+ }
+
+ switch (next_char)
+ {
+ case '[':
+ out->id = TOK_OPEN_SQUARE;
+ break;
+
+ case '{':
+ out->id = TOK_OPEN_CURLY;
+ break;
+
+ case ']':
+ out->id = TOK_CLOSE_SQUARE;
+ break;
+
+ case '}':
+ out->id = TOK_CLOSE_CURLY;
+ break;
+
+ case ':':
+ out->id = TOK_COLON;
+ break;
+
+ case ',':
+ out->id = TOK_COMMA;
+ break;
+
+ case '"':
+ lex_string (out);
+ break;
+
+ case '-':
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ lex_number (out, next_char);
+ break;
+
+ case 't':
+ /* Handle literal "true". */
+ if (rest_of_literal ("rue"))
+ {
+ out->id = TOK_TRUE;
+ break;
+ }
+ else
+ goto err;
+
+ case 'f':
+ /* Handle literal "false". */
+ if (rest_of_literal ("alse"))
+ {
+ out->id = TOK_FALSE;
+ break;
+ }
+ else
+ goto err;
+
+ case 'n':
+ /* Handle literal "null". */
+ if (rest_of_literal ("ull"))
+ {
+ out->id = TOK_NULL;
+ break;
+ }
+ else
+ goto err;
+
+ err:
+ default:
+ out->id = TOK_ERROR;
+ out->u.string = xasprintf ("unexpected character: %c", next_char);
+ break;
+ }
+}
+
+/* Having consumed an open-quote character from the lexer's buffer, attempt
+ to lex the rest of a JSON string, writing the result to OUT (or TOK_ERROR)
+ if an error occurred.
+ (ECMA-404 section 9; RFC 7159 section 7). */
+
+void
+lexer::lex_string (token *out)
+{
+ auto_vec<unichar> content;
+ bool still_going = true;
+ while (still_going)
+ {
+ unichar uc;
+ if (!get_char (uc))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("EOF within string");
+ return;
+ }
+ switch (uc)
+ {
+ case '"':
+ still_going = false;
+ break;
+ case '\\':
+ {
+ unichar next_char;
+ if (!get_char (next_char))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("EOF within string");;
+ return;
+ }
+ switch (next_char)
+ {
+ case '"':
+ case '\\':
+ case '/':
+ content.safe_push (next_char);
+ break;
+
+ case 'b':
+ content.safe_push ('\b');
+ break;
+
+ case 'f':
+ content.safe_push ('\f');
+ break;
+
+ case 'n':
+ content.safe_push ('\n');
+ break;
+
+ case 'r':
+ content.safe_push ('\r');
+ break;
+
+ case 't':
+ content.safe_push ('\t');
+ break;
+
+ case 'u':
+ {
+ unichar result = 0;
+ for (int i = 0; i < 4; i++)
+ {
+ unichar hexdigit;
+ if (!get_char (hexdigit))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("EOF within string");
+ return;
+ }
+ result <<= 4;
+ if (hexdigit >= '0' && hexdigit <= '9')
+ result += hexdigit - '0';
+ else if (hexdigit >= 'a' && hexdigit <= 'f')
+ result += (hexdigit - 'a') + 10;
+ else if (hexdigit >= 'A' && hexdigit <= 'F')
+ result += (hexdigit - 'A') + 10;
+ else
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("bogus hex char");
+ return;
+ }
+ }
+ content.safe_push (result);
+ }
+ break;
+
+ default:
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("unrecognized escape char");
+ return;
+ }
+ }
+ break;
+
+ default:
+ /* Reject unescaped control characters U+0000 through U+001F
+ (ECMA-404 section 9 para 1; RFC 7159 section 7 para 1). */
+ if (uc <= 0x1f)
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("unescaped control char");
+ return;
+ }
+
+ /* Otherwise, add regular unicode code point. */
+ content.safe_push (uc);
+ break;
+ }
+ }
+
+ out->id = TOK_STRING;
+
+ auto_vec<char> utf8_buf;
+ // FIXME: adapted from libcpp/charset.c:one_cppchar_to_utf8
+ for (unsigned i = 0; i < content.length (); i++)
+ {
+ static const uchar masks[6] = { 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
+ static const uchar limits[6] = { 0x80, 0xE0, 0xF0, 0xF8, 0xFC, 0xFE };
+ size_t nbytes;
+ uchar buf[6], *p = &buf[6];
+ unichar c = content[i];
+
+ nbytes = 1;
+ if (c < 0x80)
+ *--p = c;
+ else
+ {
+ do
+ {
+ *--p = ((c & 0x3F) | 0x80);
+ c >>= 6;
+ nbytes++;
+ }
+ while (c >= 0x3F || (c & limits[nbytes-1]));
+ *--p = (c | masks[nbytes-1]);
+ }
+
+ while (p < &buf[6])
+ utf8_buf.safe_push (*p++);
+ }
+
+ out->u.string = XNEWVEC (char, utf8_buf.length () + 1);
+ for (unsigned i = 0; i < utf8_buf.length (); i++)
+ out->u.string[i] = utf8_buf[i];
+ out->u.string[utf8_buf.length ()] = '\0';
+
+ // FIXME: leaks? have a json_context do the allocation
+}
+
+/* Having consumed FIRST_CHAR, an initial digit or '-' character from
+ the lexer's buffer attempt to lex the rest of a JSON number, writing
+ the result to OUT (or TOK_ERROR) if an error occurred.
+ (ECMA-404 section 8; RFC 7159 section 6). */
+
+void
+lexer::lex_number (token *out, unichar first_char)
+{
+ bool negate = false;
+ double value = 0.0;
+ if (first_char == '-')
+ {
+ negate = true;
+ if (!get_char (first_char))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("expected digit");
+ return;
+ }
+ }
+
+ if (first_char == '0')
+ value = 0.0;
+ else if (!ISDIGIT (first_char))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("expected digit");
+ return;
+ }
+ else
+ {
+ /* Got a nonzero digit; expect zero or more digits. */
+ value = first_char - '0';
+ while (1)
+ {
+ unichar uc;
+ if (!get_char (uc))
+ break;
+ if (ISDIGIT (uc))
+ {
+ value *= 10;
+ value += uc -'0';
+ continue;
+ }
+ else
+ {
+ unget_char ();
+ break;
+ }
+ }
+ }
+
+ /* Optional '.', followed by one or more decimals. */
+ unichar next_char;
+ if (get_char (next_char))
+ {
+ if (next_char == '.')
+ {
+ /* Parse decimal digits. */
+ bool had_digit = false;
+ // FIXME: does this lose too much precision?
+ double digit_factor = 0.1;
+ while (get_char (next_char))
+ {
+ if (!ISDIGIT (next_char))
+ {
+ unget_char ();
+ break;
+ }
+ value += (next_char - '0') * digit_factor;
+ digit_factor *= 0.1;
+ had_digit = true;
+ }
+ if (!had_digit)
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("expected digit");
+ return;
+ }
+ }
+ else
+ unget_char ();
+ }
+
+ /* Parse 'e' and 'E'. */
+ unichar exponent_char;
+ if (get_char (exponent_char))
+ {
+ if (exponent_char == 'e' || exponent_char == 'E')
+ {
+ /* Optional +/-. */
+ unichar sign_char;
+ int exponent = 0;
+ bool negate_exponent = false;
+ bool had_exponent_digit = false;
+ if (!get_char (sign_char))
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("EOF within exponent");
+ return;
+ }
+ if (sign_char == '-')
+ negate_exponent = true;
+ else if (sign_char == '+')
+ ;
+ else if (ISDIGIT (sign_char))
+ {
+ exponent = sign_char - '0';
+ had_exponent_digit = true;
+ }
+ else
+ {
+ out->id = TOK_ERROR;
+ out->u.string
+ = xstrdup ("expected '-','+' or digit within exponent");
+ return;
+ }
+
+ /* One or more digits (we might have seen the digit above,
+ though). */
+ while (1)
+ {
+ unichar uc;
+ if (!get_char (uc))
+ break;
+ if (ISDIGIT (uc))
+ {
+ exponent *= 10;
+ exponent += uc -'0';
+ had_exponent_digit = true;
+ continue;
+ }
+ else
+ {
+ unget_char ();
+ break;
+ }
+ }
+ if (!had_exponent_digit)
+ {
+ out->id = TOK_ERROR;
+ out->u.string = xstrdup ("expected digit within exponent");
+ return;
+ }
+ if (negate_exponent)
+ exponent = -exponent;
+ /* FIXME: better way to do this? */
+ value = value * pow (10, exponent);
+ }
+ else
+ unget_char ();
+ }
+
+ if (negate)
+ value = -value;
+
+ out->id = TOK_NUMBER;
+ out->u.number = value;
+}
+
+/* Determine if the next characters to be lexed match SUFFIX.
+ SUFFIX must be pure ASCII.
+ If so, consume the characters and return true.
+ Otherwise, return false. */
+
+bool
+lexer::rest_of_literal (const char *suffix)
+{
+ int suffix_idx = 0;
+ int buf_idx = m_next_char_idx;
+ while (1)
+ {
+ if (suffix[suffix_idx] == '\0')
+ {
+ m_next_char_idx += suffix_idx;
+ return true;
+ }
+ if (buf_idx >= (int)m_buffer.length ())
+ return false;
+ /* This assumes that suffix is ASCII. */
+ if (m_buffer[buf_idx] != (unichar)suffix[suffix_idx])
+ return false;
+ buf_idx++;
+ suffix_idx++;
+ }
+}
+
+/* parser's ctor. */
+
+parser::parser (char **err_out)
+: m_lexer (), m_err_out (err_out)
+{
+ gcc_assert (err_out);
+ gcc_assert (*err_out == NULL);
+ *err_out = NULL;
+}
+
+/* Add LENGTH bytes of UTF-8 encoded text from UTF8_BUF to this parser's
+ lexer's buffer. */
+
+bool
+parser::add_utf8 (size_t length, const char *utf8_buf, char **err_out)
+{
+ return m_lexer.add_utf8 (length, utf8_buf, err_out);
+}
+
+/* Parse a JSON value (object, array, number, string, or literal).
+ (ECMA-404 section 5; RFC 7159 section 3). */
+
+value *
+parser::parse_value (int depth)
+{
+ const token *tok = m_lexer.peek ();
+
+ /* Avoid stack overflow with deeply-nested inputs; RFC 7159 section 9
+ states: "An implementation may set limits on the maximum depth
+ of nesting.".
+
+ Ideally we'd avoid this limit (e.g. by rewriting parse_value,
+ parse_object, and parse_array into a single function with a vec of
+ state). */
+ const int MAX_DEPTH = 100;
+ if (depth >= MAX_DEPTH)
+ {
+ error_at (tok->index, "maximum nesting depth exceeded: %i", MAX_DEPTH);
+ return NULL;
+ }
+
+ switch (tok->id)
+ {
+ case TOK_OPEN_CURLY:
+ return parse_object (depth);
+
+ case TOK_STRING:
+ {
+ string *result = new string (tok->u.string);
+ m_lexer.consume ();
+ return result;
+ }
+
+ case TOK_OPEN_SQUARE:
+ return parse_array (depth);
+
+ case TOK_NUMBER:
+ {
+ number *result = new number (tok->u.number);
+ m_lexer.consume ();
+ return result;
+ }
+
+ case TOK_TRUE:
+ {
+ literal *result = new literal (JSON_TRUE);
+ m_lexer.consume ();
+ return result;
+ }
+
+ case TOK_FALSE:
+ {
+ literal *result = new literal (JSON_FALSE);
+ m_lexer.consume ();
+ return result;
+ }
+
+ case TOK_NULL:
+ {
+ literal *result = new literal (JSON_NULL);
+ m_lexer.consume ();
+ return result;
+ }
+
+ default:
+ error_at (tok->index, "unexpected token: %s", token_id_name[tok->id]);
+ return NULL;
+ }
+}
+
+/* Parse a JSON object.
+ (ECMA-404 section 6; RFC 7159 section 4). */
+
+object *
+parser::parse_object (int depth)
+{
+ require (TOK_OPEN_CURLY);
+
+ object *result = new object ();
+
+ const token *tok = m_lexer.peek ();
+ if (tok->id == TOK_CLOSE_CURLY)
+ {
+ require (TOK_CLOSE_CURLY);
+ return result;
+ }
+ if (tok->id != TOK_STRING)
+ {
+ error_at (tok->index, "expected string for object key");
+ return result;
+ }
+ while (!seen_error_p ())
+ {
+ tok = m_lexer.peek ();
+ if (tok->id != TOK_STRING)
+ {
+ error_at (tok->index, "expected string for object key");
+ return result;
+ }
+ char *key = xstrdup (tok->u.string);
+ m_lexer.consume ();
+
+ require (TOK_COLON);
+
+ value *v = parse_value (depth + 1);
+ if (!v)
+ {
+ free (key);
+ return result;
+ }
+ /* We don't enforce uniqueness for keys. */
+ result->set (key, v);
+ free (key);
+
+ tok = m_lexer.peek ();
+ if (tok->id == TOK_COMMA)
+ {
+ m_lexer.consume ();
+ continue;
+ }
+ else
+ {
+ require (TOK_CLOSE_CURLY);
+ break;
+ }
+ }
+ return result;
+}
+
+/* Parse a JSON array.
+ (ECMA-404 section 7; RFC 7159 section 5). */
+
+array *
+parser::parse_array (int depth)
+{
+ require (TOK_OPEN_SQUARE);
+
+ array *result = new array ();
+
+ const token *tok = m_lexer.peek ();
+ if (tok->id == TOK_CLOSE_SQUARE)
+ {
+ m_lexer.consume ();
+ return result;
+ }
+
+ while (!seen_error_p ())
+ {
+ value *v = parse_value (depth + 1);
+ if (!v)
+ return result;
+
+ result->append (v);
+
+ tok = m_lexer.peek ();
+ if (tok->id == TOK_COMMA)
+ {
+ m_lexer.consume ();
+ continue;
+ }
+ else
+ {
+ require (TOK_CLOSE_SQUARE);
+ break;
+ }
+ }
+
+ return result;
+}
+
+/* Require an EOF, or fail if there is surplus input. */
+
+void
+parser::require_eof ()
+{
+ require (TOK_EOF);
+}
+
+/* Consume the next token, issuing an error if it is not of kind TOK_ID. */
+
+void
+parser::require (enum token_id tok_id)
+{
+ const token *tok = m_lexer.peek ();
+ if (tok->id != tok_id)
+ {
+ if (tok->id == TOK_ERROR)
+ error_at (tok->index, "expected %s; got bad token: %s",
+ token_id_name[tok_id], tok->u.string);
+ else
+ error_at (tok->index, "expected %s; got %s", token_id_name[tok_id],
+ token_id_name[tok->id]);
+ }
+ m_lexer.consume ();
+}
+
+/* Issue a parsing error. If this is the first error that has occurred on
+ the parser, store it within the parser's m_err_out (the buffer will
+ eventually need to be free by the caller of the parser).
+ Otherwise the error is discarded.
+
+ TODO: maybe provide a callback so that client code can print all errors? */
+
+void
+parser::error_at (int index, const char *fmt, ...)
+{
+ va_list ap;
+ va_start (ap, fmt);
+ char *formatted = xvasprintf (fmt, ap);
+ va_end (ap);
+
+ char *msg_with_index = xasprintf ("error at index %i: %s",
+ index, formatted);
+ free (formatted);
+
+ if (0)
+ fprintf (stderr, "%s\n", msg_with_index);
+ if (*m_err_out == NULL)
+ *m_err_out = msg_with_index;
+ else
+ free (msg_with_index);
+}
+
+/* Attempt to parse the UTF-8 encoded buffer at UTF8_BUF
+ of the given LENGTH.
+ If successful, return a non-NULL json::value *.
+ if there was a problem, return NULL and write an error
+ message to err_out, which must be freed by the caller. */
+
+value *
+json::parse_utf8_string (size_t length, const char *utf8_buf,
+ char **err_out)
+{
+ gcc_assert (err_out);
+ gcc_assert (*err_out == NULL);
+
+ parser p (err_out);
+ if (!p.add_utf8 (length, utf8_buf, err_out))
+ return NULL;
+ value *result = p.parse_value (0);
+ if (!p.seen_error_p ())
+ p.require_eof ();
+ if (p.seen_error_p ())
+ {
+ gcc_assert (*err_out);
+ delete result;
+ return NULL;
+ }
+ return result;
+}
+
+/* Attempt to parse the nil-terminated UTF-8 encoded buffer at
+ UTF8_BUF.
+ If successful, return a non-NULL json::value *.
+ if there was a problem, return NULL and write an error
+ message to err_out, which must be freed by the caller. */
+
+value *
+json::parse_utf8_string (const char *utf8, char **err_out)
+{
+ return parse_utf8_string (strlen (utf8), utf8, err_out);
+}
+
+
+#if CHECKING_P
+
+namespace selftest {
+
+/* Selftests. */
+
+/* Verify that JV->to_str () equals EXPECTED_JSON. */
+
+static void
+assert_to_str_eq (const char *expected_json, json::value *jv)
+{
+ char *json = jv->to_str ();
+ ASSERT_STREQ (expected_json, json);
+ free (json);
+}
+
+/* FIXME. */
+
+static void
+test_parse_string ()
+{
+ char *err = NULL;
+ json::value *jv = parse_utf8_string ("\"foo\"", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_STRING, jv->get_kind ());
+ ASSERT_STREQ ("foo", ((json::string *)jv)->get_string ());
+ assert_to_str_eq ("\"foo\"", jv);
+
+ json::value *clone = jv->clone ();
+ ASSERT_EQ (JSON_STRING, clone->get_kind ());
+ ASSERT_STREQ ("foo", ((json::string *)clone)->get_string ());
+ assert_to_str_eq ("\"foo\"", clone);
+ delete clone;
+ delete jv;
+
+ const char *contains_quotes = "\"before \\\"quoted\\\" after\"";
+ jv = parse_utf8_string (contains_quotes, &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_STRING, jv->get_kind ());
+ ASSERT_STREQ ("before \"quoted\" after", ((json::string *)jv)->get_string ());
+ assert_to_str_eq (contains_quotes, jv);
+ delete jv;
+
+ /* Test of non-ASCII input. This string is the Japanese word "mojibake",
+ written as C octal-escaped UTF-8. */
+ const char *mojibake = (/* Opening quote. */
+ "\""
+ /* U+6587 CJK UNIFIED IDEOGRAPH-6587
+ UTF-8: 0xE6 0x96 0x87
+ C octal escaped UTF-8: \346\226\207. */
+ "\346\226\207"
+ /* U+5B57 CJK UNIFIED IDEOGRAPH-5B57
+ UTF-8: 0xE5 0xAD 0x97
+ C octal escaped UTF-8: \345\255\227. */
+ "\345\255\227"
+ /* U+5316 CJK UNIFIED IDEOGRAPH-5316
+ UTF-8: 0xE5 0x8C 0x96
+ C octal escaped UTF-8: \345\214\226. */
+ "\345\214\226"
+ /* U+3051 HIRAGANA LETTER KE
+ UTF-8: 0xE3 0x81 0x91
+ C octal escaped UTF-8: \343\201\221. */
+ "\343\201\221"
+ /* Closing quote. */
+ "\"");
+ jv = parse_utf8_string (mojibake, &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_STRING, jv->get_kind ());
+ /* Result of get_string should be UTF-8 encoded, without quotes. */
+ ASSERT_STREQ ("\346\226\207" "\345\255\227" "\345\214\226" "\343\201\221",
+ ((json::string *)jv)->get_string ());
+ /* Result of dump should be UTF-8 encoded, with quotes. */
+ assert_to_str_eq (mojibake, jv);
+ delete jv;
+
+ /* Test of \u-escaped unicode. This is "mojibake" again, as above. */
+ const char *escaped_unicode = "\"\\u6587\\u5b57\\u5316\\u3051\"";
+ jv = parse_utf8_string (escaped_unicode, &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_STRING, jv->get_kind ());
+ /* Result of get_string should be UTF-8 encoded, without quotes. */
+ ASSERT_STREQ ("\346\226\207" "\345\255\227" "\345\214\226" "\343\201\221",
+ ((json::string *)jv)->get_string ());
+ /* Result of dump should be UTF-8 encoded, with quotes. */
+ assert_to_str_eq (mojibake, jv);
+ delete jv;
+}
+
+/* FIXME. */
+
+static void
+test_parse_number ()
+{
+ json::value *jv, *clone;
+
+ char *err = NULL;
+ jv = parse_utf8_string ("42", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (42.0, ((json::number *)jv)->get ());
+ assert_to_str_eq ("42", jv);
+ clone = jv->clone ();
+ ASSERT_EQ (JSON_NUMBER, clone->get_kind ());
+ delete clone;
+ delete jv;
+
+ /* Negative number. */
+ jv = parse_utf8_string ("-17", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (-17.0, ((json::number *)jv)->get ());
+ assert_to_str_eq ("-17", jv);
+ delete jv;
+
+ /* Decimal. */
+ jv = parse_utf8_string ("3.141", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (3.141, ((json::number *)jv)->get ());
+ assert_to_str_eq ("3.141", jv);
+ delete jv;
+
+ /* Exponents. */
+ jv = parse_utf8_string ("3.141e+0", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (3.141, ((json::number *)jv)->get ());
+ assert_to_str_eq ("3.141", jv);
+ delete jv;
+
+ jv = parse_utf8_string ("42e2", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (4200, ((json::number *)jv)->get ());
+ assert_to_str_eq ("4200", jv);
+ delete jv;
+
+ jv = parse_utf8_string ("42e-1", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_NUMBER, jv->get_kind ());
+ ASSERT_EQ (4.2, ((json::number *)jv)->get ());
+ assert_to_str_eq ("4.2", jv);
+ delete jv;
+
+}
+
+/* FIXME. */
+
+static void
+test_parse_array ()
+{
+ json::value *jv, *clone;
+
+ char *err = NULL;
+ jv = parse_utf8_string ("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_EQ (JSON_ARRAY, jv->get_kind ());
+ json::array *arr = static_cast <json::array *> (jv);
+ ASSERT_EQ (10, arr->get_length ());
+ for (int i = 0; i < 10; i++)
+ {
+ json::value *element = arr->get (i);
+ ASSERT_EQ (JSON_NUMBER, element->get_kind ());
+ ASSERT_EQ (i, ((json::number *)element)->get ());
+ }
+ assert_to_str_eq ("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]", jv);
+
+ clone = jv->clone ();
+ ASSERT_EQ (JSON_ARRAY, clone->get_kind ());
+ arr = static_cast <json::array *> (clone);
+ ASSERT_EQ (10, arr->get_length ());
+ for (int i = 0; i < 10; i++)
+ {
+ json::value *element = arr->get (i);
+ ASSERT_EQ (JSON_NUMBER, element->get_kind ());
+ ASSERT_EQ (i, ((json::number *)element)->get ());
+ }
+ assert_to_str_eq ("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]", clone);
+ delete clone;
+
+ delete jv;
+}
+
+/* FIXME. */
+
+static void
+test_parse_object ()
+{
+ char *err = NULL;
+ json::value *jv
+ = parse_utf8_string ("{\"foo\": \"bar\", \"baz\": [42, null]}", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ ASSERT_EQ (JSON_OBJECT, jv->get_kind ());
+ json::object *jo = static_cast <json::object *> (jv);
+
+ json::value *foo_value = jo->get ("foo");
+ ASSERT_TRUE (foo_value != NULL);
+ ASSERT_EQ (JSON_STRING, foo_value->get_kind ());
+ ASSERT_STREQ ("bar", ((json::string *)foo_value)->get_string ());
+
+ json::value *baz_value = jo->get ("baz");
+ ASSERT_TRUE (baz_value != NULL);
+ ASSERT_EQ (JSON_ARRAY, baz_value->get_kind ());
+
+ json::array *baz_array = (json::array *)baz_value;
+ ASSERT_EQ (2, baz_array->get_length ());
+ ASSERT_EQ (42, baz_array->get (0)->as_number ()->get ());
+ ASSERT_EQ (JSON_NULL, baz_array->get (1)->get_kind ());
+
+ // TODO: error-handling
+ // TODO: partial document
+
+ /* We can't use assert_to_str_eq since ordering is not guaranteed. */
+
+ json::value *clone = jv->clone ();
+ ASSERT_EQ (JSON_OBJECT, clone->get_kind ());
+ ASSERT_EQ (JSON_STRING, clone->as_object ()->get ("foo")->get_kind ());
+ delete clone;
+
+ delete jv;
+}
+
+/* Verify that the literals "true", "false" and "null" are parsed,
+ dumped, and are clonable. */
+
+static void
+test_parse_literals ()
+{
+ json::value *jv, *clone;
+ char *err = NULL;
+ jv = parse_utf8_string ("true", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ ASSERT_EQ (JSON_TRUE, jv->get_kind ());
+ assert_to_str_eq ("true", jv);
+ clone = jv->clone ();
+ ASSERT_EQ (JSON_TRUE, clone->get_kind ());
+ delete clone;
+ delete jv;
+
+ jv = parse_utf8_string ("false", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ ASSERT_EQ (JSON_FALSE, jv->get_kind ());
+ assert_to_str_eq ("false", jv);
+ clone = jv->clone ();
+ ASSERT_EQ (JSON_FALSE, clone->get_kind ());
+ delete clone;
+ delete jv;
+
+ jv = parse_utf8_string ("null", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ ASSERT_EQ (JSON_NULL, jv->get_kind ());
+ assert_to_str_eq ("null", jv);
+ clone = jv->clone ();
+ ASSERT_EQ (JSON_NULL, clone->get_kind ());
+ delete clone;
+ delete jv;
+}
+
+/* FIXME. */
+
+static void
+test_parse_jsonrpc ()
+{
+ char *err = NULL;
+ const char *request
+ = ("{\"jsonrpc\": \"2.0\", \"method\": \"subtract\","
+ " \"params\": [42, 23], \"id\": 1}");
+ json::value *jv = parse_utf8_string (request, &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ delete jv;
+}
+
+/* FIXME. */
+
+static void
+test_parse_empty_object ()
+{
+ char *err = NULL;
+ json::value *jv = parse_utf8_string ("{}", &err);
+ ASSERT_EQ (NULL, err);
+ ASSERT_TRUE (jv != NULL);
+ ASSERT_EQ (JSON_OBJECT, jv->get_kind ());
+ assert_to_str_eq ("{}", jv);
+ delete jv;
+}
+
+/* FIXME. */
+
+static void
+test_error_empty_string ()
+{
+ char *err = NULL;
+ json::value *jv = parse_utf8_string ("", &err);
+ ASSERT_STREQ ("error at index 0: unexpected token: EOF", err);
+ ASSERT_TRUE (jv == NULL);
+ free (err);
+}
+
+/* FIXME. */
+
+static void
+test_error_missing_comma ()
+{
+ char *err = NULL;
+ /* 01234567. */
+ const char *json = "[0, 1 2]";
+ json::value *jv = parse_utf8_string (json, &err);
+ ASSERT_STREQ ("error at index 6: expected ']'; got number",
+ err);
+ // FIXME: unittest the lexer?
+ ASSERT_TRUE (jv == NULL);
+ free (err);
+}
+
+/* Run all of the selftests within this file. */
+
+void
+json_c_tests ()
+{
+ test_parse_string ();
+ test_parse_number ();
+ test_parse_array ();
+ test_parse_object ();
+ test_parse_literals ();
+ test_parse_jsonrpc ();
+ test_parse_empty_object ();
+ test_error_empty_string ();
+ test_error_missing_comma ();
+
+ /* FIXME: tests for roundtripping (noting that we don't preserve
+ object key ordering). */
+
+ /* FIXME: cloning. */
+}
+
+} // namespace selftest
+
+#endif /* #if CHECKING_P */
diff --git a/gcc/json.h b/gcc/json.h
new file mode 100644
index 0000000..aedf84a
--- /dev/null
+++ b/gcc/json.h
@@ -0,0 +1,214 @@
+/* JSON parsing
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef GCC_JSON_H
+#define GCC_JSON_H
+
+/* Implementation of JSON, a lightweight data-interchange format.
+
+ See http://www.json.org/
+ and http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
+ and https://tools.ietf.org/html/rfc7159
+
+ Supports parsing text into a DOM-like tree of json::value *, dumping
+ json::value * to text. */
+
+namespace json
+{
+
+/* Forward decls of json::value and its subclasses (using indentation
+ to denote inheritance. */
+
+class value;
+ class object;
+ class array;
+ class number;
+ class string;
+ class literal;
+
+/* An enum for discriminating the subclasses of json::value. */
+
+enum kind
+{
+ /* class json::object. */
+ JSON_OBJECT,
+
+ /* class json::array. */
+ JSON_ARRAY,
+
+ /* class json::number. */
+ JSON_NUMBER,
+
+ /* class json::string. */
+ JSON_STRING,
+
+ /* class json::literal uses these three values to identify the
+ particular literal. */
+ JSON_TRUE,
+ JSON_FALSE,
+ JSON_NULL
+};
+
+/* Base class of JSON value. */
+
+class value
+{
+ public:
+ virtual ~value () {}
+ virtual enum kind get_kind () const = 0;
+ virtual void print (pretty_printer *pp) const = 0;
+
+ /* Create a deep copy of the value, returning a value which must be
+ deleted by the caller. */
+ virtual value *clone () const = 0;
+
+ char *to_str () const;
+ void dump (FILE *) const;
+
+ /* Methods for dynamically casting a value to one of the subclasses,
+ returning NULL if the value is of the wrong kind. */
+ const object *as_object () const;
+ const array *as_array () const;
+ const number *as_number () const;
+ const string *as_string () const;
+
+ /* Convenience accessors for attempting to perform key/value lookups
+ on this value as if it were an json::object.
+
+ On success, return true and write the value to OUT_VALUE.
+ On failure, return false and write an error message to OUT_ERR
+ (which must be freed by the caller). */
+ bool get_value_by_key (const char *name, const value *&out_value,
+ char *&out_err) const;
+ bool get_int_by_key (const char *name, int &out_value, char *&out_err) const;
+ bool get_string_by_key (const char *name, const char *&out_value,
+ char *&out_err) const;
+ bool get_array_by_key (const char *name, const array *&out_value,
+ char *&out_err) const;
+
+ /* As above, but the key is optional. THIS must still be an object,
+ though. */
+ bool get_optional_value_by_key (const char *name, const value *&out_value,
+ char *&out_err) const;
+ bool get_optional_string_by_key (const char *name, const char *&out_value,
+ char *&out_err) const;
+};
+
+/* Subclass of value for objects: an unordered collection of
+ key/value pairs. */
+
+class object : public value
+{
+ public:
+ ~object ();
+
+ enum kind get_kind () const FINAL OVERRIDE { return JSON_OBJECT; }
+ void print (pretty_printer *pp) const FINAL OVERRIDE;
+ value *clone () const FINAL OVERRIDE;
+
+ value *get (const char *key) const;
+ value *get_if_nonnull (const char *key) const;
+
+ void set (const char *key, value *v);
+
+ private:
+ typedef hash_map <char *, value *,
+ simple_hashmap_traits<nofree_string_hash, value *> > map_t;
+ map_t m_map;
+};
+
+/* Subclass of value for arrays. */
+
+class array : public value
+{
+ public:
+ ~array ();
+
+ enum kind get_kind () const FINAL OVERRIDE { return JSON_ARRAY; }
+ void print (pretty_printer *pp) const FINAL OVERRIDE;
+ value *clone () const FINAL OVERRIDE;
+
+ unsigned get_length () const { return m_elements.length (); }
+ value *get (int idx) const { return m_elements[idx]; }
+ void append (value *v) { m_elements.safe_push (v); }
+
+ private:
+ auto_vec<value *> m_elements;
+};
+
+/* Subclass of value for numbers. */
+
+class number : public value
+{
+ public:
+ number (double value) : m_value (value) {}
+
+ enum kind get_kind () const FINAL OVERRIDE { return JSON_NUMBER; }
+ void print (pretty_printer *pp) const FINAL OVERRIDE;
+ value *clone () const FINAL OVERRIDE;
+
+ double get () const { return m_value; }
+
+ private:
+ double m_value;
+};
+
+/* Subclass of value for strings. */
+
+class string : public value
+{
+ public:
+ string (const char *utf8) : m_utf8 (xstrdup (utf8)) {}
+ ~string () { free (m_utf8); }
+
+ enum kind get_kind () const FINAL OVERRIDE { return JSON_STRING; }
+ void print (pretty_printer *pp) const FINAL OVERRIDE;
+ value *clone () const FINAL OVERRIDE;
+
+ const char *get_string () const { return m_utf8; }
+
+ private:
+ char *m_utf8;
+};
+
+/* Subclass of value for the three JSON literals "true", "false",
+ and "null". */
+
+class literal : public value
+{
+ public:
+ literal (enum kind kind) : m_kind (kind) {}
+
+ enum kind get_kind () const FINAL OVERRIDE { return m_kind; }
+ void print (pretty_printer *pp) const FINAL OVERRIDE;
+ value *clone () const FINAL OVERRIDE;
+
+ private:
+ enum kind m_kind;
+};
+
+/* Declarations for parsing JSON to a json::value * tree. */
+
+extern value *parse_utf8_string (size_t length, const char *utf8_buf,
+ char **err_out);
+extern value *parse_utf8_string (const char *utf8, char **err_out);
+
+} // namespace json
+
+#endif /* GCC_JSON_H */
diff --git a/gcc/selftest-run-tests.c b/gcc/selftest-run-tests.c
index 01e3504..a8668f4 100644
--- a/gcc/selftest-run-tests.c
+++ b/gcc/selftest-run-tests.c
@@ -67,6 +67,7 @@ selftest::run_tests ()
fibonacci_heap_c_tests ();
typed_splay_tree_c_tests ();
blt_c_tests ();
+ json_c_tests ();
/* Mid-level data structures. */
input_c_tests ();
diff --git a/gcc/selftest.h b/gcc/selftest.h
index 583bdb2..281658b 100644
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -184,6 +184,7 @@ extern void ggc_tests_c_tests ();
extern void hash_map_tests_c_tests ();
extern void hash_set_tests_c_tests ();
extern void input_c_tests ();
+extern void json_c_tests ();
extern void pretty_print_c_tests ();
extern void read_rtl_function_c_tests ();
extern void rtl_tests_c_tests ();
--
1.8.5.3