Add support for converting literals to canonical form

5 files changed, 216 insertions, 6 deletions

diff --git a/src/canon.c b/src/canon.c
new file mode 100644
index 00000000..99351f9e
--- /dev/null
+++ b/src/canon.c
@@ -0,0 +1,194 @@
+/*
+  Copyright 2019-2020 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "cursor.h"
+#include "namespaces.h"
+#include "node.h"
+#include "statement.h"
+#include "string_utils.h"
+#include "world.h"
+
+#include "exess/exess.h"
+#include "serd/serd.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+  const SerdWorld* world;
+  const SerdSink*  target;
+  SerdCanonFlags   flags;
+} SerdCanonData;
+
+static ExessResult
+make_canonical(SerdNode** const out, const SerdNode* const SERD_NONNULL node)
+{
+  *out = NULL;
+
+  const char*     str      = serd_node_string(node);
+  const SerdNode* datatype = serd_node_datatype(node);
+  ExessResult     r        = {EXESS_SUCCESS, 0};
+
+  if (serd_node_type(datatype) != SERD_URI) {
+    r.status = EXESS_BAD_VALUE;
+    return r;
+  }
+
+  const char* datatype_uri = serd_node_string(datatype);
+  if (!strcmp(datatype_uri, NS_RDF "langString")) {
+    *out = serd_new_string(serd_node_string_view(node));
+    return r;
+  }
+
+  const ExessDatatype value_type = exess_datatype_from_uri(datatype_uri);
+  if (value_type == EXESS_NOTHING) {
+    return r;
+  }
+
+  // Measure canonical form to know how much space to allocate for node
+  ExessVariant variant = exess_make_nothing(EXESS_SUCCESS);
+  if (exess_datatype_is_bounded(value_type)) {
+    r = exess_read_variant(&variant, value_type, str);
+    if (!r.status) {
+      r = exess_write_variant(variant, 0, NULL);
+    }
+  } else {
+    r = exess_write_canonical(str, value_type, 0, NULL);
+  }
+
+  if (r.status) {
+    return r;
+  }
+
+  // Allocate node
+  const size_t datatype_uri_len = serd_node_length(datatype);
+  const size_t len              = serd_node_pad_size(r.count);
+  const size_t total_len        = sizeof(SerdNode) + len + datatype_uri_len;
+
+  SerdNode* const result =
+    serd_node_malloc(total_len, SERD_HAS_DATATYPE, SERD_LITERAL);
+
+  // Write canonical form directly into node
+  char* buf = serd_node_buffer(result);
+  if (exess_datatype_is_bounded(value_type)) {
+    r               = exess_write_variant(variant, r.count + 1, buf);
+    result->n_bytes = r.count;
+  } else {
+    r               = exess_write_canonical(str, value_type, r.count + 1, buf);
+    result->n_bytes = r.count;
+  }
+
+  if (r.status) {
+    serd_node_free(result);
+    return r;
+  }
+
+  SerdNode* const datatype_node = result + 1 + (len / sizeof(SerdNode));
+  char* const     datatype_buf  = serd_node_buffer(datatype_node);
+
+  datatype_node->n_bytes = datatype_uri_len;
+  datatype_node->type    = SERD_URI;
+  memcpy(datatype_buf, datatype_uri, datatype_uri_len + 1);
+
+  /* serd_node_check_padding(datatype_node); */
+  /* serd_node_check_padding(result); */
+
+  *out = result;
+  return r;
+}
+
+static SerdStatus
+serd_canon_on_statement(SerdCanonData*       data,
+                        SerdStatementFlags   flags,
+                        const SerdStatement* statement)
+{
+  const SerdNode* object = serd_statement_object(statement);
+  if (serd_node_type(object) != SERD_LITERAL || !serd_node_datatype(object)) {
+    return serd_sink_write_statement(data->target, flags, statement);
+  }
+
+  SerdNode*   normo = NULL;
+  ExessResult r     = make_canonical(&normo, object);
+  if (r.status) {
+    const bool         lax = (data->flags & SERD_CANON_LAX);
+    const SerdLogLevel level =
+      lax ? SERD_LOG_LEVEL_WARNING : SERD_LOG_LEVEL_ERR;
+
+    if (statement->cursor) {
+      // Adjust column to point at the exact error location in the literal
+      const SerdCursor cursor = {statement->cursor->file,
+                                 statement->cursor->line,
+                                 statement->cursor->col + 1 +
+                                   (unsigned)r.count};
+
+      serd_world_logf_internal(data->world,
+                               SERD_ERR_INVALID,
+                               level,
+                               &cursor,
+                               "invalid literal (%s)\n",
+                               exess_strerror(r.status));
+    } else {
+      serd_world_logf_internal(data->world,
+                               SERD_ERR_INVALID,
+                               level,
+                               NULL,
+                               "invalid literal (%s)\n",
+                               exess_strerror(r.status));
+    }
+
+    if (!lax) {
+      return SERD_ERR_INVALID;
+    }
+  }
+
+  if (!normo) {
+    return serd_sink_write_statement(data->target, flags, statement);
+  }
+
+  const SerdStatus st = serd_sink_write(data->target,
+                                        flags,
+                                        statement->nodes[0],
+                                        statement->nodes[1],
+                                        normo,
+                                        statement->nodes[3]);
+  serd_node_free(normo);
+  return st;
+}
+
+static SerdStatus
+serd_canon_on_event(SerdCanonData* data, const SerdEvent* event)
+{
+  return (event->type == SERD_STATEMENT)
+           ? serd_canon_on_statement(
+               data, event->statement.flags, event->statement.statement)
+           : serd_sink_write_event(data->target, event);
+}
+
+SerdSink*
+serd_canon_new(const SerdWorld*     world,
+               const SerdSink*      target,
+               const SerdCanonFlags flags)
+{
+  SerdCanonData* const data = (SerdCanonData*)calloc(1, sizeof(SerdCanonData));
+
+  data->world  = world;
+  data->target = target;
+  data->flags  = flags;
+
+  return serd_sink_new(data, (SerdEventFunc)serd_canon_on_event, free);
+}
diff --git a/src/node.c b/src/node.c
index 7d1177e4..0283b14f 100644
--- a/src/node.c
+++ b/src/node.c
@@ -48,7 +48,7 @@ typedef struct {
 static SerdNode*
 serd_new_from_uri(const SerdURIView uri, const SerdURIView base);
 
-static size_t
+size_t
 serd_node_pad_size(const size_t n_bytes)
 {
   const size_t pad  = sizeof(SerdNode) - (n_bytes + 2) % sizeof(SerdNode);
diff --git a/src/node.h b/src/node.h
index 5206b109..6470d939 100644
--- a/src/node.h
+++ b/src/node.h
@@ -62,6 +62,10 @@ void
 serd_node_set(SerdNode* SERD_NONNULL* SERD_NONNULL dst,
               const SerdNode* SERD_NONNULL         src);
 
+SERD_CONST_FUNC
+size_t
+serd_node_pad_size(const size_t n_bytes);
+
 SERD_PURE_FUNC
 size_t
 serd_node_total_size(const SerdNode* SERD_NONNULL node);
diff --git a/src/serdi.c b/src/serdi.c
index 70c52682..b028b862 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -55,6 +55,7 @@ print_usage(const char* name, bool error)
   fprintf(os, "Usage: %s [OPTION]... INPUT...\n", name);
   fprintf(os, "Read and write RDF syntax.\n");
   fprintf(os, "Use - for INPUT to read from standard input.\n\n");
+  fprintf(os, "  -C           Convert literals to canonical form.\n");
   fprintf(os, "  -I BASE_URI  Input base URI.\n");
   fprintf(os, "  -V           Validate inputs.\n");
   fprintf(os, "  -a           Write ASCII output if possible.\n");
@@ -150,6 +151,7 @@ main(int argc, char** argv)
   bool            osyntax_set   = false;
   bool            validate      = false;
   bool            use_model     = false;
+  bool            normalise     = false;
   bool            quiet         = false;
   size_t          stack_size    = 4194304;
   const char*     input_string  = NULL;
@@ -163,7 +165,9 @@ main(int argc, char** argv)
       break;
     }
 
-    if (argv[a][1] == 'I') {
+    if (argv[a][1] == 'C') {
+      normalise = true;
+    } else if (argv[a][1] == 'I') {
       if (++a == argc) {
         return missing_arg(argv[0], 'I');
       }
@@ -316,7 +320,7 @@ main(int argc, char** argv)
 
   SerdModel*      model    = NULL;
   SerdSink*       inserter = NULL;
-  const SerdSink* sink     = NULL;
+  const SerdSink* out_sink = NULL;
   if (use_model) {
     const SerdModelFlags flags =
       SERD_INDEX_SPO | (input_has_graphs ? SERD_INDEX_GRAPHS : 0u) |
@@ -324,9 +328,16 @@ main(int argc, char** argv)
 
     model    = serd_model_new(world, flags);
     inserter = serd_inserter_new(model, env, NULL);
-    sink     = inserter;
+    out_sink = inserter;
   } else {
-    sink = serd_writer_sink(writer);
+    out_sink = serd_writer_sink(writer);
+  }
+
+  const SerdSink* sink = out_sink;
+
+  SerdSink* canon = NULL;
+  if (normalise) {
+    sink = canon = serd_canon_new(world, out_sink, reader_flags);
   }
 
   if (quiet) {
@@ -410,6 +421,7 @@ main(int argc, char** argv)
     serd_range_free(range);
   }
 
+  serd_sink_free(canon);
   serd_sink_free(inserter);
   serd_model_free(model);
   serd_writer_free(writer);
diff --git a/src/string_utils.h b/src/string_utils.h
index 0e9eee43..a302bc49 100644
--- a/src/string_utils.h
+++ b/src/string_utils.h
@@ -62,7 +62,7 @@ is_xdigit(const int c)
 }
 
 static inline bool
-is_space(const char c)
+is_space(const int c)
 {
   switch (c) {
   case ' ':