// Copyright 2011-2023 David Robillard // SPDX-License-Identifier: ISC #include "byte_sink.h" #include "env.h" #include "node.h" #include "serd_internal.h" #include "sink.h" #include "stack.h" #include "string_utils.h" #include "system.h" #include "try.h" #include "uri_utils.h" #include "world.h" #include "serd/attributes.h" #include "serd/buffer.h" #include "serd/env.h" #include "serd/event.h" #include "serd/node.h" #include "serd/sink.h" #include "serd/statement.h" #include "serd/status.h" #include "serd/stream.h" #include "serd/string_view.h" #include "serd/syntax.h" #include "serd/uri.h" #include "serd/world.h" #include "serd/writer.h" #include #include #include #include #include #include #include #include typedef enum { CTX_NAMED, ///< Normal non-anonymous context CTX_BLANK, ///< Anonymous blank node CTX_LIST, ///< Anonymous list } ContextType; typedef struct { ContextType type; SerdStatementFlags flags; SerdNode* graph; SerdNode* subject; SerdNode* predicate; bool predicates; bool comma_indented; } WriteContext; static const WriteContext WRITE_CONTEXT_NULL = {CTX_NAMED, 0U, NULL, NULL, NULL, 0U, 0U}; typedef enum { SEP_NONE, ///< Sentinel before the start of a document SEP_NODE, ///< Sentinel after a node SEP_NEWLINE, ///< Sentinel after a node SEP_END_DIRECT, ///< End of a directive (like "@prefix") SEP_END_S, ///< End of a subject ('.') SEP_END_P, ///< End of a predicate (';') SEP_END_O, ///< End of a named object (',') SEP_JOIN_O_AN, ///< End of anonymous object (',') before a named one SEP_JOIN_O_NA, ///< End of named object (',') before an anonymous one SEP_JOIN_O_AA, ///< End of anonymous object (',') before another SEP_S_P, ///< Between a subject and predicate (whitespace) SEP_P_O, ///< Between a predicate and object (whitespace) SEP_ANON_BEGIN, ///< Start of anonymous node ('[') SEP_ANON_S_P, ///< Between anonymous subject and predicate (whitespace) SEP_ANON_END, ///< End of anonymous node (']') SEP_LIST_BEGIN, ///< Start of list ('(') SEP_LIST_SEP, ///< List separator (newline) SEP_LIST_END, ///< End of list (')') SEP_TLIST_BEGIN, ///< Start of terse list ('(') SEP_TLIST_SEP, ///< Terse list separator (space) SEP_TLIST_END, ///< End of terse list (')') SEP_GRAPH_BEGIN, ///< Start of graph ('{') SEP_GRAPH_END, ///< End of graph ('}') } Sep; typedef uint32_t SepMask; ///< Bitfield of separator flags typedef struct { char sep; ///< Sep character int indent; ///< Indent delta SepMask pre_space_after; ///< Leading space if after given seps SepMask pre_line_after; ///< Leading newline if after given seps SepMask post_line_after; ///< Trailing newline if after given seps } SepRule; #define SEP_EACH (~(SepMask)0) #define M(s) (1U << (s)) #define NIL '\0' static const SepRule rules[] = { {NIL, +0, SEP_NONE, SEP_NONE, SEP_NONE}, {NIL, +0, SEP_NONE, SEP_NONE, SEP_NONE}, {'\n', 0, SEP_NONE, SEP_NONE, SEP_NONE}, {'.', +0, SEP_EACH, SEP_NONE, SEP_NONE}, {'.', +0, SEP_EACH, SEP_NONE, SEP_NONE}, {';', +0, SEP_EACH, SEP_NONE, SEP_EACH}, {',', +0, SEP_EACH, SEP_NONE, SEP_EACH}, {',', +0, SEP_EACH, SEP_NONE, SEP_EACH}, {',', +0, SEP_EACH, SEP_NONE, SEP_EACH}, {',', +0, SEP_EACH, SEP_NONE, SEP_NONE}, {NIL, +1, SEP_NONE, SEP_NONE, SEP_EACH}, {' ', +0, SEP_NONE, SEP_NONE, SEP_NONE}, {'[', +1, M(SEP_JOIN_O_AA), M(SEP_TLIST_BEGIN) | M(SEP_TLIST_SEP), SEP_NONE}, {NIL, +1, SEP_NONE, SEP_NONE, M(SEP_ANON_BEGIN)}, {']', -1, SEP_NONE, ~M(SEP_ANON_BEGIN), SEP_NONE}, {'(', +1, M(SEP_JOIN_O_AA), SEP_NONE, SEP_EACH}, {NIL, +0, SEP_NONE, SEP_EACH, SEP_NONE}, {')', -1, SEP_NONE, SEP_EACH, SEP_NONE}, {'(', +1, SEP_NONE, SEP_NONE, SEP_NONE}, {NIL, +0, SEP_EACH, SEP_NONE, SEP_NONE}, {')', -1, SEP_NONE, SEP_NONE, SEP_NONE}, {'{', +1, SEP_EACH, SEP_NONE, SEP_EACH}, {'}', -1, SEP_NONE, SEP_NONE, SEP_EACH}, }; #undef NIL #undef M #undef SEP_EACH struct SerdWriterImpl { SerdWorld* world; SerdSink iface; SerdSyntax syntax; SerdWriterFlags flags; SerdEnv* env; SerdNode* root_node; SerdURIView root_uri; SerdStack anon_stack; SerdByteSink byte_sink; WriteContext context; char* bprefix; size_t bprefix_len; Sep last_sep; int indent; }; typedef enum { WRITE_STRING, WRITE_LONG_STRING } TextContext; typedef enum { RESET_GRAPH = 1U << 0U, RESET_INDENT = 1U << 1U } ResetFlag; SERD_NODISCARD static SerdStatus serd_writer_set_base_uri(SerdWriter* writer, const SerdNode* uri); SERD_NODISCARD static SerdStatus serd_writer_set_prefix(SerdWriter* writer, const SerdNode* name, const SerdNode* uri); SERD_NODISCARD static SerdStatus write_node(SerdWriter* writer, const SerdNode* node, SerdField field, SerdStatementFlags flags); SERD_NODISCARD static bool supports_abbrev(const SerdWriter* writer) { return writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG; } SERD_NODISCARD static bool supports_uriref(const SerdWriter* writer) { return writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG; } static SerdStatus free_context(WriteContext* const ctx) { serd_node_free(ctx->graph); serd_node_free(ctx->subject); serd_node_free(ctx->predicate); ctx->graph = NULL; ctx->subject = NULL; ctx->predicate = NULL; return SERD_SUCCESS; } SERD_LOG_FUNC(3, 4) static SerdStatus w_err(SerdWriter* writer, SerdStatus st, const char* fmt, ...) { /* TODO: This results in errors with no file information, which is not helpful when re-serializing a file (particularly for "undefined namespace prefix" errors. The statement sink API needs to be changed to add a Cursor parameter so the source can notify the writer of the statement origin for better error reporting. */ va_list args; // NOLINT(cppcoreguidelines-init-variables) va_start(args, fmt); serd_world_verrorf(writer->world, st, fmt, args); va_end(args); return st; } static inline SerdNode* ctx(SerdWriter* writer, const SerdField field) { SerdNode* node = (field == SERD_SUBJECT) ? writer->context.subject : (field == SERD_PREDICATE) ? writer->context.predicate : (field == SERD_GRAPH) ? writer->context.graph : NULL; return node && node->type ? node : NULL; } SERD_NODISCARD static SerdStatus push_context(SerdWriter* const writer, const ContextType type, const SerdStatementFlags flags, const SerdNode* const graph, const SerdNode* const subject, const SerdNode* const predicate) { // Push the current context to the stack void* const top = serd_stack_push(&writer->anon_stack, sizeof(WriteContext)); if (!top) { return SERD_BAD_STACK; } *(WriteContext*)top = writer->context; // Update the current context const WriteContext current = {type, flags, serd_node_copy(graph), serd_node_copy(subject), serd_node_copy(predicate), 0U, 0U}; writer->context = current; return SERD_SUCCESS; } static void pop_context(SerdWriter* writer) { // Replace the current context with the top of the stack free_context(&writer->context); writer->context = *(WriteContext*)(writer->anon_stack.buf + writer->anon_stack.size - sizeof(WriteContext)); // Pop the top of the stack away serd_stack_pop(&writer->anon_stack, sizeof(WriteContext)); } SERD_NODISCARD static size_t sink(const void* buf, size_t len, SerdWriter* writer) { const size_t written = serd_byte_sink_write(buf, len, &writer->byte_sink); if (written != len) { if (errno) { char message[1024] = {0}; serd_system_strerror(errno, message, sizeof(message)); w_err(writer, SERD_BAD_WRITE, "write error (%s)\n", message); } else { w_err(writer, SERD_BAD_WRITE, "write error\n"); } } return written; } SERD_NODISCARD static inline SerdStatus esink(const void* buf, size_t len, SerdWriter* writer) { return sink(buf, len, writer) == len ? SERD_SUCCESS : SERD_BAD_WRITE; } // Write a single character, as an escape for single byte characters // (Caller prints any single byte characters that don't need escaping) static size_t write_character(SerdWriter* writer, const uint8_t* utf8, size_t* size, SerdStatus* st) { char escape[11] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; const uint32_t c = parse_utf8_char(utf8, size); switch (*size) { case 0: *st = w_err(writer, SERD_BAD_TEXT, "invalid UTF-8 start: %X\n", utf8[0]); return 0; case 1: snprintf(escape, sizeof(escape), "\\u%04X", utf8[0]); return sink(escape, 6, writer); default: break; } if (!(writer->flags & SERD_WRITE_ASCII)) { // Write UTF-8 character directly to UTF-8 output return sink(utf8, *size, writer); } if (c <= 0xFFFF) { snprintf(escape, sizeof(escape), "\\u%04X", c); return sink(escape, 6, writer); } snprintf(escape, sizeof(escape), "\\U%08X", c); return sink(escape, 10, writer); } static bool uri_must_escape(const int c) { switch (c) { case ' ': case '"': case '<': case '>': case '\\': case '^': case '`': case '{': case '|': case '}': return true; default: return !in_range(c, 0x20, 0x7E); } } static size_t write_uri(SerdWriter* writer, const char* utf8, size_t n_bytes, SerdStatus* st) { size_t len = 0; for (size_t i = 0; i < n_bytes;) { size_t j = i; // Index of next character that must be escaped for (; j < n_bytes; ++j) { if (uri_must_escape(utf8[j])) { break; } } // Bulk write all characters up to this special one const size_t n_bulk = sink(&utf8[i], j - i, writer); len += n_bulk; if (n_bulk != j - i) { *st = SERD_BAD_WRITE; return len; } if ((i = j) == n_bytes) { break; // Reached end } // Write UTF-8 character size_t size = 0; len += write_character(writer, (const uint8_t*)utf8 + i, &size, st); i += size; if (*st && !(writer->flags & SERD_WRITE_LAX)) { break; } if (size == 0) { // Corrupt input, write percent-encoded bytes and scan to next start char escape[4] = {0, 0, 0, 0}; for (; i < n_bytes && (utf8[i] & 0x80); ++i) { snprintf(escape, sizeof(escape), "%%%02X", (uint8_t)utf8[i]); len += sink(escape, 3, writer); } } } return len; } SERD_NODISCARD static SerdStatus ewrite_uri(SerdWriter* writer, const char* utf8, size_t n_bytes) { SerdStatus st = SERD_SUCCESS; write_uri(writer, utf8, n_bytes, &st); return (st == SERD_BAD_WRITE || !(writer->flags & SERD_WRITE_LAX)) ? st : SERD_SUCCESS; } SERD_NODISCARD static SerdStatus write_uri_from_node(SerdWriter* writer, const SerdNode* node) { return ewrite_uri(writer, serd_node_string(node), serd_node_length(node)); } static bool lname_must_escape(const char c) { /* This arbitrary list of characters, most of which have nothing to do with Turtle, must be handled as special cases here because the RDF and SPARQL WGs are apparently intent on making the once elegant Turtle a baroque and inconsistent mess, throwing elegance and extensibility completely out the window for no good reason. Note '-', '.', and '_' are also in PN_LOCAL_ESC, but are valid unescaped in local names, so they are not escaped here. */ switch (c) { case '\'': case '!': case '#': case '$': case '%': case '&': case '(': case ')': case '*': case '+': case ',': case '/': case ';': case '=': case '?': case '@': case '~': return true; default: break; } return false; } SERD_NODISCARD static SerdStatus write_lname(SerdWriter* writer, const char* utf8, size_t n_bytes) { SerdStatus st = SERD_SUCCESS; for (size_t i = 0; i < n_bytes; ++i) { size_t j = i; // Index of next character that must be escaped for (; j < n_bytes; ++j) { if (lname_must_escape(utf8[j])) { break; } } // Bulk write all characters up to this special one TRY(st, esink(&utf8[i], j - i, writer)); if ((i = j) == n_bytes) { break; // Reached end } // Write escape TRY(st, esink("\\", 1, writer)); TRY(st, esink(&utf8[i], 1, writer)); } return st; } SERD_NODISCARD static SerdStatus write_text(SerdWriter* writer, TextContext ctx, const char* utf8, size_t n_bytes) { size_t n_consecutive_quotes = 0; SerdStatus st = SERD_SUCCESS; for (size_t i = 0; !st && i < n_bytes;) { if (utf8[i] != '"') { n_consecutive_quotes = 0; } // Fast bulk write for long strings of printable ASCII size_t j = i; for (; j < n_bytes; ++j) { if (utf8[j] == '\\' || utf8[j] == '"' || (!in_range(utf8[j], 0x20, 0x7E))) { break; } } st = esink(&utf8[i], j - i, writer); if ((i = j) == n_bytes) { break; // Reached end } const char in = utf8[i++]; if (ctx == WRITE_LONG_STRING) { n_consecutive_quotes = (in == '\"') ? (n_consecutive_quotes + 1) : 0; switch (in) { case '\\': st = esink("\\\\", 2, writer); continue; case '\b': st = esink("\\b", 2, writer); continue; case '\n': case '\r': case '\t': case '\f': st = esink(&in, 1, writer); // Write character as-is continue; case '\"': if (n_consecutive_quotes >= 3 || i == n_bytes) { // Two quotes in a row, or quote at string end, escape st = esink("\\\"", 2, writer); } else { st = esink(&in, 1, writer); } continue; default: break; } } else { switch (in) { case '\\': st = esink("\\\\", 2, writer); continue; case '\n': st = esink("\\n", 2, writer); continue; case '\r': st = esink("\\r", 2, writer); continue; case '\t': st = esink("\\t", 2, writer); continue; case '"': st = esink("\\\"", 2, writer); continue; default: break; } if (writer->syntax == SERD_TURTLE) { switch (in) { case '\b': st = esink("\\b", 2, writer); continue; case '\f': st = esink("\\f", 2, writer); continue; default: break; } } } // Write UTF-8 character size_t size = 0; write_character(writer, (const uint8_t*)utf8 + i - 1, &size, &st); if (st && !(writer->flags & SERD_WRITE_LAX)) { return st; } if (size == 0) { // Corrupt input, write replacement character and scan to the next start st = esink(replacement_char, sizeof(replacement_char), writer); for (; i < n_bytes && (utf8[i] & 0x80); ++i) { } } else { i += size - 1; } } return (writer->flags & SERD_WRITE_LAX) ? SERD_SUCCESS : st; } typedef struct { SerdWriter* writer; SerdStatus status; } UriSinkContext; SERD_NODISCARD static size_t uri_sink(const void* buf, size_t size, size_t nmemb, void* stream) { (void)size; assert(size == 1); UriSinkContext* const context = (UriSinkContext*)stream; SerdWriter* const writer = context->writer; return write_uri(writer, (const char*)buf, nmemb, &context->status); } SERD_NODISCARD static SerdStatus write_newline(SerdWriter* writer, bool terse) { SerdStatus st = SERD_SUCCESS; if (terse || (writer->flags & SERD_WRITE_TERSE)) { return esink(" ", 1, writer); } TRY(st, esink("\n", 1, writer)); for (int i = 0; i < writer->indent; ++i) { TRY(st, esink("\t", 1, writer)); } return st; } SERD_NODISCARD static SerdStatus write_top_level_sep(SerdWriter* writer) { return (writer->last_sep && !(writer->flags & SERD_WRITE_TERSE)) ? write_newline(writer, false) : SERD_SUCCESS; } SERD_NODISCARD static SerdStatus write_sep(SerdWriter* writer, const SerdStatementFlags flags, Sep sep) { SerdStatus st = SERD_SUCCESS; const SepRule* const rule = &rules[sep]; const bool pre_line = (rule->pre_line_after & (1U << writer->last_sep)); const bool post_line = (rule->post_line_after & (1U << writer->last_sep)); const bool terse = (((flags & SERD_TERSE_S) && (flags & SERD_LIST_S)) || ((flags & SERD_TERSE_O) && (flags & SERD_LIST_O))); if (terse && sep >= SEP_LIST_BEGIN && sep <= SEP_LIST_END) { sep = (Sep)((int)sep + 3); // Switch to corresponding terse separator } // Adjust indent, but tolerate if it would become negative if (rule->indent && (pre_line || post_line)) { writer->indent = ((rule->indent >= 0 || writer->indent >= -rule->indent) ? writer->indent + rule->indent : 0); } // If this is the first comma, bump the increment for the following object if (sep == SEP_END_O && !writer->context.comma_indented) { ++writer->indent; writer->context.comma_indented = true; } // Write newline or space before separator if necessary if (pre_line) { TRY(st, write_newline(writer, terse)); } else if (rule->pre_space_after & (1U << writer->last_sep)) { TRY(st, esink(" ", 1, writer)); } // Write actual separator string if (rule->sep) { TRY(st, esink(&rule->sep, 1, writer)); } // Write newline after separator if necessary if (post_line) { TRY(st, write_newline(writer, terse)); if (rule->post_line_after != ~(SepMask)0U) { writer->last_sep = SEP_NEWLINE; } } // Reset context and write a blank line after ends of subjects if (sep == SEP_END_S || sep == SEP_END_DIRECT) { writer->indent = ctx(writer, SERD_GRAPH) ? 1 : 0; writer->context.predicates = false; writer->context.comma_indented = false; if (!terse) { TRY(st, esink("\n", 1, writer)); } } writer->last_sep = sep; return st; } static void free_anon_stack(SerdWriter* writer) { while (!serd_stack_is_empty(&writer->anon_stack)) { pop_context(writer); } } static SerdStatus reset_context(SerdWriter* writer, const unsigned flags) { free_anon_stack(writer); if (writer->context.predicate) { memset(writer->context.predicate, 0, sizeof(SerdNode)); } if (writer->context.subject) { memset(writer->context.subject, 0, sizeof(SerdNode)); } if (flags & RESET_GRAPH) { if (writer->context.graph) { memset(writer->context.graph, 0, sizeof(SerdNode)); } } if (flags & RESET_INDENT) { writer->indent = 0; } writer->context.type = CTX_NAMED; writer->context.predicates = false; writer->context.comma_indented = false; return SERD_SUCCESS; } SERD_NODISCARD static SerdStatus write_literal(SerdWriter* const writer, const SerdNode* const node, const SerdStatementFlags flags) { SerdStatus st = SERD_SUCCESS; const SerdNode* const datatype = serd_node_datatype(node); const SerdNode* const lang = serd_node_language(node); const char* const node_str = serd_node_string(node); const char* const type_uri = datatype ? serd_node_string(datatype) : NULL; if (supports_abbrev(writer) && type_uri) { if (!strncmp(type_uri, NS_XSD, sizeof(NS_XSD) - 1) && (!strcmp(type_uri + sizeof(NS_XSD) - 1, "boolean") || !strcmp(type_uri + sizeof(NS_XSD) - 1, "integer"))) { return esink(node_str, node->length, writer); } if (!strncmp(type_uri, NS_XSD, sizeof(NS_XSD) - 1) && !strcmp(type_uri + sizeof(NS_XSD) - 1, "decimal") && strchr(node_str, '.') && node_str[node->length - 1] != '.') { /* xsd:decimal literals without trailing digits, e.g. "5.", can not be written bare in Turtle. We could add a 0 which is prettier, but changes the text and breaks round tripping. */ return esink(node_str, node->length, writer); } } if (supports_abbrev(writer) && (node->flags & (SERD_HAS_NEWLINE | SERD_HAS_QUOTE))) { TRY(st, esink("\"\"\"", 3, writer)); TRY(st, write_text(writer, WRITE_LONG_STRING, node_str, node->length)); TRY(st, esink("\"\"\"", 3, writer)); } else { TRY(st, esink("\"", 1, writer)); TRY(st, write_text(writer, WRITE_STRING, node_str, node->length)); TRY(st, esink("\"", 1, writer)); } if (lang && serd_node_string(lang)) { TRY(st, esink("@", 1, writer)); TRY(st, esink(serd_node_string(lang), lang->length, writer)); } else if (type_uri) { TRY(st, esink("^^", 2, writer)); return write_node(writer, datatype, (SerdField)-1, flags); } return st; } // Return true iff `buf` is a valid prefixed name prefix or suffix static bool is_name(const char* buf, const size_t len) { // TODO: This is more strict than it should be for (size_t i = 0; i < len; ++i) { if (!(is_alpha(buf[i]) || is_digit(buf[i]))) { return false; } } return true; } SERD_NODISCARD static SerdStatus write_uri_node(SerdWriter* const writer, const SerdNode* const node, const SerdField field) { SerdStatus st = SERD_SUCCESS; const SerdNode* prefix = NULL; SerdStringView suffix = {NULL, 0}; const char* const node_str = serd_node_string(node); const bool has_scheme = serd_uri_string_has_scheme(node_str); if (supports_abbrev(writer)) { if (field == SERD_PREDICATE && !strcmp(node_str, NS_RDF "type")) { return esink("a", 1, writer); } if (!strcmp(node_str, NS_RDF "nil")) { return esink("()", 2, writer); } if (has_scheme && !(writer->flags & SERD_WRITE_UNQUALIFIED) && serd_env_qualify(writer->env, node, &prefix, &suffix) && is_name(serd_node_string(prefix), serd_node_length(prefix)) && is_name(suffix.data, suffix.length)) { TRY(st, write_uri_from_node(writer, prefix)); TRY(st, esink(":", 1, writer)); return ewrite_uri(writer, suffix.data, suffix.length); } } if (!has_scheme && !supports_uriref(writer) && !serd_env_base_uri(writer->env)) { return w_err(writer, SERD_BAD_ARG, "syntax does not support URI reference <%s>\n", node_str); } TRY(st, esink("<", 1, writer)); if (!(writer->flags & SERD_WRITE_UNRESOLVED) && serd_env_base_uri(writer->env)) { const SerdURIView base_uri = serd_env_base_uri_view(writer->env); SerdURIView uri = serd_parse_uri(node_str); SerdURIView abs_uri = serd_resolve_uri(uri, base_uri); bool rooted = uri_is_under(&base_uri, &writer->root_uri); const SerdURIView* root = rooted ? &writer->root_uri : &base_uri; UriSinkContext ctx = {writer, SERD_SUCCESS}; if (!supports_abbrev(writer) || !uri_is_under(&abs_uri, root)) { serd_write_uri(abs_uri, uri_sink, &ctx); } else { serd_write_uri(serd_relative_uri(uri, base_uri), uri_sink, &ctx); } } else { TRY(st, write_uri_from_node(writer, node)); } return esink(">", 1, writer); } SERD_NODISCARD static SerdStatus write_curie(SerdWriter* const writer, const SerdNode* const node) { const char* const node_str = serd_node_string(node); SerdStringView prefix = {NULL, 0}; SerdStringView suffix = {NULL, 0}; SerdStatus st = SERD_SUCCESS; // In fast-and-loose Turtle/TriG mode CURIEs are simply passed through const bool fast = (writer->flags & (SERD_WRITE_UNQUALIFIED | SERD_WRITE_UNRESOLVED)); if (!supports_abbrev(writer) || !fast) { if ((st = serd_env_expand(writer->env, node, &prefix, &suffix))) { return w_err(writer, st, "undefined namespace prefix '%s'\n", node_str); } } if (!supports_abbrev(writer)) { TRY(st, esink("<", 1, writer)); TRY(st, ewrite_uri(writer, prefix.data, prefix.length)); TRY(st, ewrite_uri(writer, suffix.data, suffix.length)); TRY(st, esink(">", 1, writer)); } else { TRY(st, write_lname(writer, node_str, node->length)); } return st; } SERD_NODISCARD static SerdStatus write_blank(SerdWriter* const writer, const SerdNode* node, const SerdField field, const SerdStatementFlags flags) { SerdStatus st = SERD_SUCCESS; const char* const node_str = serd_node_string(node); if (supports_abbrev(writer)) { if ((field == SERD_SUBJECT && (flags & SERD_ANON_S)) || (field == SERD_OBJECT && (flags & SERD_ANON_O))) { return write_sep(writer, flags, SEP_ANON_BEGIN); } if ((field == SERD_SUBJECT && (flags & SERD_LIST_S)) || (field == SERD_OBJECT && (flags & SERD_LIST_O))) { return write_sep(writer, flags, SEP_LIST_BEGIN); } if ((field == SERD_SUBJECT && (flags & SERD_EMPTY_S)) || (field == SERD_OBJECT && (flags & SERD_EMPTY_O))) { return esink("[]", 2, writer); } } TRY(st, esink("_:", 2, writer)); if (writer->bprefix && !strncmp(node_str, writer->bprefix, writer->bprefix_len)) { TRY(st, esink(node_str + writer->bprefix_len, node->length - writer->bprefix_len, writer)); } else { TRY(st, esink(node_str, node->length, writer)); } return st; } SERD_NODISCARD static SerdStatus write_node(SerdWriter* const writer, const SerdNode* const node, const SerdField field, const SerdStatementFlags flags) { SerdStatus st = SERD_SUCCESS; switch (node->type) { case SERD_LITERAL: st = write_literal(writer, node, flags); break; case SERD_URI: st = write_uri_node(writer, node, field); break; case SERD_CURIE: st = write_curie(writer, node); break; case SERD_BLANK: st = write_blank(writer, node, field, flags); break; } if (node->type != SERD_BLANK) { writer->last_sep = SEP_NODE; } return st; } static bool is_resource(const SerdNode* node) { return node && node->type > SERD_LITERAL; } SERD_NODISCARD static SerdStatus write_pred(SerdWriter* writer, SerdStatementFlags flags, const SerdNode* pred) { SerdStatus st = SERD_SUCCESS; TRY(st, write_node(writer, pred, SERD_PREDICATE, flags)); TRY(st, write_sep(writer, flags, SEP_P_O)); serd_node_set(&writer->context.predicate, pred); writer->context.predicates = true; writer->context.comma_indented = false; return st; } SERD_NODISCARD static SerdStatus write_list_next(SerdWriter* const writer, const SerdStatementFlags flags, const SerdNode* const predicate, const SerdNode* const object) { SerdStatus st = SERD_SUCCESS; if (!strcmp(serd_node_string(object), NS_RDF "nil")) { TRY(st, write_sep(writer, writer->context.flags, SEP_LIST_END)); return SERD_FAILURE; } if (!strcmp(serd_node_string(predicate), NS_RDF "first")) { TRY(st, write_node(writer, object, SERD_OBJECT, flags)); } else { TRY(st, write_sep(writer, writer->context.flags, SEP_LIST_SEP)); } return st; } SERD_NODISCARD static SerdStatus terminate_context(SerdWriter* writer) { SerdStatus st = SERD_SUCCESS; if (ctx(writer, SERD_SUBJECT)) { TRY(st, write_sep(writer, writer->context.flags, SEP_END_S)); } if (ctx(writer, SERD_GRAPH)) { TRY(st, write_sep(writer, writer->context.flags, SEP_GRAPH_END)); } return st; } SERD_NODISCARD static SerdStatus serd_writer_write_statement(SerdWriter* const writer, const SerdStatementFlags flags, const SerdStatement* const statement) { assert(!((flags & SERD_ANON_S) && (flags & SERD_LIST_S))); assert(!((flags & SERD_EMPTY_S) && (flags & SERD_LIST_S))); assert(!((flags & SERD_ANON_O) && (flags & SERD_LIST_O))); assert(!((flags & SERD_EMPTY_O) && (flags & SERD_LIST_O))); SerdStatus st = SERD_SUCCESS; const SerdNode* const subject = serd_statement_subject(statement); const SerdNode* const predicate = serd_statement_predicate(statement); const SerdNode* const object = serd_statement_object(statement); const SerdNode* const graph = serd_statement_graph(statement); if (!is_resource(subject) || !is_resource(predicate) || !object || ((flags & SERD_ANON_S) && (flags & SERD_LIST_S)) || // Nonsense ((flags & SERD_ANON_O) && (flags & SERD_LIST_O)) || // Nonsense ((flags & SERD_ANON_S) && (flags & SERD_TERSE_S)) || // Unsupported ((flags & SERD_ANON_O) && (flags & SERD_TERSE_O))) { // Unsupported return SERD_BAD_ARG; } // Simple case: write a line of NTriples or NQuads if (writer->syntax == SERD_NTRIPLES || writer->syntax == SERD_NQUADS) { TRY(st, write_node(writer, subject, SERD_SUBJECT, flags)); TRY(st, esink(" ", 1, writer)); TRY(st, write_node(writer, predicate, SERD_PREDICATE, flags)); TRY(st, esink(" ", 1, writer)); TRY(st, write_node(writer, object, SERD_OBJECT, flags)); if (writer->syntax == SERD_NQUADS && graph) { TRY(st, esink(" ", 1, writer)); TRY(st, write_node(writer, graph, SERD_GRAPH, flags)); } TRY(st, esink(" .\n", 3, writer)); return SERD_SUCCESS; } // Separate graphs if necessary if ((graph && !serd_node_equals(graph, writer->context.graph)) || (!graph && ctx(writer, SERD_GRAPH))) { TRY(st, terminate_context(writer)); reset_context(writer, RESET_GRAPH | RESET_INDENT); if (graph) { TRY(st, write_top_level_sep(writer)); TRY(st, write_node(writer, graph, SERD_GRAPH, flags)); TRY(st, write_sep(writer, flags, SEP_GRAPH_BEGIN)); serd_node_set(&writer->context.graph, graph); } } if (writer->context.type == CTX_LIST) { // Continue a list if (!strcmp(serd_node_string(predicate), NS_RDF "first") && !strcmp(serd_node_string(object), NS_RDF "nil")) { return esink("()", 2, writer); } TRY_FAILING(st, write_list_next(writer, flags, predicate, object)); if (st == SERD_FAILURE) { // Reached end of list pop_context(writer); return SERD_SUCCESS; } } else if (serd_node_equals(subject, writer->context.subject)) { if (serd_node_equals(predicate, writer->context.predicate)) { // Elide S P (write O) const Sep last = writer->last_sep; const bool anon_o = flags & SERD_ANON_O; const bool list_o = flags & SERD_LIST_O; const bool open_o = anon_o || list_o; const bool after_end = (last == SEP_ANON_END) || (last == SEP_LIST_END); TRY(st, write_sep(writer, flags, after_end ? (open_o ? SEP_JOIN_O_AA : SEP_JOIN_O_AN) : (open_o ? SEP_JOIN_O_NA : SEP_END_O))); } else { // Elide S (write P and O) if (writer->context.comma_indented && !(flags & SERD_ANON_S)) { --writer->indent; writer->context.comma_indented = false; } const bool first = !ctx(writer, SERD_PREDICATE); TRY(st, write_sep(writer, flags, first ? SEP_S_P : SEP_END_P)); TRY(st, write_pred(writer, flags, predicate)); } TRY(st, write_node(writer, object, SERD_OBJECT, flags)); } else { // No abbreviation if (serd_stack_is_empty(&writer->anon_stack)) { if (ctx(writer, SERD_SUBJECT)) { TRY(st, write_sep(writer, flags, SEP_END_S)); } if (writer->last_sep == SEP_END_S || writer->last_sep == SEP_END_DIRECT) { TRY(st, write_top_level_sep(writer)); } TRY(st, write_node(writer, subject, SERD_SUBJECT, flags)); if ((flags & (SERD_ANON_S | SERD_LIST_S))) { TRY(st, write_sep(writer, flags, SEP_ANON_S_P)); } else { TRY(st, write_sep(writer, flags, SEP_S_P)); } } else { TRY(st, write_sep(writer, flags, SEP_ANON_S_P)); } reset_context(writer, 0U); serd_node_set(&writer->context.subject, subject); if (!(flags & SERD_LIST_S)) { TRY(st, write_pred(writer, flags, predicate)); } TRY(st, write_node(writer, object, SERD_OBJECT, flags)); } if (flags & (SERD_ANON_S | SERD_LIST_S)) { // Push context for anonymous or list subject const bool is_list = (flags & SERD_LIST_S); TRY(st, push_context(writer, is_list ? CTX_LIST : CTX_BLANK, flags, graph, subject, is_list ? NULL : predicate)); } if (flags & (SERD_ANON_O | SERD_LIST_O)) { // Push context for anonymous or list object if necessary TRY(st, push_context(writer, (flags & SERD_LIST_O) ? CTX_LIST : CTX_BLANK, flags, graph, object, NULL)); } return st; } SERD_NODISCARD static SerdStatus serd_writer_end_anon(SerdWriter* writer, const SerdNode* node) { SerdStatus st = SERD_SUCCESS; if (writer->syntax == SERD_NTRIPLES || writer->syntax == SERD_NQUADS) { return SERD_SUCCESS; } if (serd_stack_is_empty(&writer->anon_stack)) { return w_err(writer, SERD_BAD_EVENT, "unexpected end of anonymous node\n"); } // Write the end separator ']' and pop the context TRY(st, write_sep(writer, writer->context.flags, SEP_ANON_END)); pop_context(writer); if (writer->context.predicate && serd_node_equals(node, writer->context.subject)) { // Now-finished anonymous node is the new subject with no other context memset(writer->context.predicate, 0, sizeof(SerdNode)); } return st; } SERD_NODISCARD static SerdStatus serd_writer_on_event(SerdWriter* writer, const SerdEvent* event) { switch (event->type) { case SERD_BASE: return serd_writer_set_base_uri(writer, event->base.uri); case SERD_PREFIX: return serd_writer_set_prefix( writer, event->prefix.name, event->prefix.uri); case SERD_STATEMENT: return serd_writer_write_statement( writer, event->statement.flags, event->statement.statement); case SERD_END: return serd_writer_end_anon(writer, event->end.node); } return SERD_BAD_ARG; } SerdStatus serd_writer_finish(SerdWriter* writer) { const SerdStatus st0 = terminate_context(writer); const SerdStatus st1 = serd_byte_sink_flush(&writer->byte_sink); free_anon_stack(writer); reset_context(writer, RESET_GRAPH | RESET_INDENT); writer->last_sep = SEP_NONE; return st0 ? st0 : st1; } SerdWriter* serd_writer_new(SerdWorld* world, SerdSyntax syntax, SerdWriterFlags flags, SerdEnv* env, SerdWriteFunc ssink, void* stream) { const WriteContext context = WRITE_CONTEXT_NULL; SerdWriter* writer = (SerdWriter*)calloc(1, sizeof(SerdWriter)); writer->world = world; writer->syntax = syntax; writer->flags = flags; writer->env = env; writer->root_node = NULL; writer->root_uri = SERD_URI_NULL; writer->anon_stack = serd_stack_new(SERD_PAGE_SIZE); writer->context = context; writer->byte_sink = serd_byte_sink_new( ssink, stream, (flags & SERD_WRITE_BULK) ? SERD_PAGE_SIZE : 1); writer->iface.handle = writer; writer->iface.on_event = (SerdEventFunc)serd_writer_on_event; return writer; } void serd_writer_chop_blank_prefix(SerdWriter* writer, const char* prefix) { free(writer->bprefix); writer->bprefix_len = 0; writer->bprefix = NULL; const size_t prefix_len = prefix ? strlen(prefix) : 0; if (prefix_len) { writer->bprefix_len = prefix_len; writer->bprefix = (char*)malloc(writer->bprefix_len + 1); memcpy(writer->bprefix, prefix, writer->bprefix_len + 1); } } SERD_NODISCARD static SerdStatus serd_writer_set_base_uri(SerdWriter* writer, const SerdNode* uri) { if (uri && serd_node_type(uri) != SERD_URI) { return SERD_BAD_ARG; } if (serd_node_equals(serd_env_base_uri(writer->env), uri)) { return SERD_SUCCESS; } const SerdStringView uri_string = uri ? serd_node_string_view(uri) : serd_empty_string(); SerdStatus st = SERD_SUCCESS; TRY(st, serd_env_set_base_uri(writer->env, uri_string)); if (uri && (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG)) { TRY(st, terminate_context(writer)); TRY(st, esink("@base <", 7, writer)); TRY(st, esink(uri_string.data, uri_string.length, writer)); TRY(st, esink(">", 1, writer)); writer->last_sep = SEP_NODE; TRY(st, write_sep(writer, writer->context.flags, SEP_END_DIRECT)); } return reset_context(writer, RESET_GRAPH | RESET_INDENT); } SerdStatus serd_writer_set_root_uri(SerdWriter* writer, const SerdNode* uri) { serd_node_free(writer->root_node); writer->root_node = NULL; writer->root_uri = SERD_URI_NULL; if (uri) { writer->root_node = serd_node_copy(uri); writer->root_uri = serd_node_uri_view(writer->root_node); } return SERD_SUCCESS; } SerdStatus serd_writer_set_prefix(SerdWriter* writer, const SerdNode* name, const SerdNode* uri) { SerdStatus st = SERD_SUCCESS; TRY(st, serd_env_set_prefix( writer->env, serd_node_string_view(name), serd_node_string_view(uri))); if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) { TRY(st, terminate_context(writer)); TRY(st, esink("@prefix ", 8, writer)); TRY(st, esink(serd_node_string(name), name->length, writer)); TRY(st, esink(": <", 3, writer)); TRY(st, ewrite_uri(writer, serd_node_string(uri), uri->length)); TRY(st, esink(">", 1, writer)); writer->last_sep = SEP_NODE; TRY(st, write_sep(writer, writer->context.flags, SEP_END_DIRECT)); } return reset_context(writer, RESET_GRAPH | RESET_INDENT); } void serd_writer_free(SerdWriter* writer) { if (!writer) { return; } serd_writer_finish(writer); free_context(&writer->context); free_anon_stack(writer); serd_stack_free(&writer->anon_stack); free(writer->bprefix); serd_byte_sink_free(&writer->byte_sink); serd_node_free(writer->root_node); free(writer); } const SerdSink* serd_writer_sink(SerdWriter* writer) { return &writer->iface; } size_t serd_buffer_sink(const void* const buf, const size_t size, const size_t nmemb, void* const stream) { assert(size == 1); (void)size; SerdBuffer* buffer = (SerdBuffer*)stream; char* new_buf = (char*)realloc(buffer->buf, buffer->len + nmemb); if (new_buf) { memcpy(new_buf + buffer->len, buf, nmemb); buffer->buf = new_buf; buffer->len += nmemb; } return nmemb; } char* serd_buffer_sink_finish(SerdBuffer* const stream) { serd_buffer_sink("", 1, 1, stream); return (char*)stream->buf; }