Replace serdi with more fine-grained tools

Especially with the new functionality, the complexity of the command-line
interface alone was really becoming unmanageable.  The serdi implementation
also had the highest cyclomatic complexity of the entire codebase by a huge
margin.

So, take a page from the Unix philosophy and split serdi into several more
finely-honed tools that can be freely composed.  Though there is still
unfortunately quite a bit of option overlap between them due to the common
details of reading RDF, I think the resulting tools are a lot easier to
understand, both from a user and a developer perspective.

1 files changed, 274 insertions, 0 deletions

diff --git a/tools/serd-sort.c b/tools/serd-sort.c
new file mode 100644
index 00000000..deb79cb5
--- /dev/null
+++ b/tools/serd-sort.c
@@ -0,0 +1,274 @@
+/*
+  Copyright 2011-2021 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 "console.h"
+
+#include "serd/serd.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Application (after parsing command-line arguments) */
+
+// All options
+typedef struct {
+  SerdCommonOptions  common;
+  const char*        root_uri;
+  const char*        input_string;
+  const char*        collation;
+  char* const*       inputs;
+  intptr_t           n_inputs;
+  SerdStatementOrder order;
+  SerdDescribeFlags  flags;
+} Options;
+
+static bool
+input_has_graphs(const Options opts)
+{
+  if (opts.common.input.syntax) {
+    return serd_syntax_has_graphs(opts.common.input.syntax);
+  }
+
+  for (intptr_t i = 0u; i < opts.n_inputs; ++i) {
+    if (serd_syntax_has_graphs(serd_guess_syntax(opts.inputs[i]))) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// Run the tool using the given options
+static SerdStatus
+run(const Options opts)
+{
+  SerdTool app = {NULL, NULL, NULL, NULL};
+
+  // Set up the writing environment
+  SerdStatus st = SERD_SUCCESS;
+  if ((st = serd_tool_setup(&app, "serd-sort", opts.common))) {
+    serd_tool_cleanup(app);
+    return st;
+  }
+
+  // Determine the default order to store statements in the model
+  const bool               with_graphs   = input_has_graphs(opts);
+  const SerdStatementOrder default_order = opts.collation ? opts.order
+                                           : with_graphs  ? SERD_ORDER_GSPO
+                                                          : SERD_ORDER_SPO;
+
+  const SerdModelFlags flags =
+    (SerdModelFlags)(with_graphs * SERD_STORE_GRAPHS);
+
+  SerdModel* const model = serd_model_new(app.world, default_order, flags);
+
+  if (!opts.collation) {
+    // If we are pretty-printing, we need an O** index
+    serd_model_add_index(model, SERD_ORDER_OPS);
+
+    if (with_graphs) {
+      // If we have graphs we still need the SPO index for finding subjects
+      serd_model_add_index(model, SERD_ORDER_SPO);
+    }
+  }
+
+  // Read all the inputs into an inserter to load the model
+  SerdSink* const inserter = serd_inserter_new(model, NULL);
+  if (st || (st = serd_read_inputs(app.world,
+                                   opts.common,
+                                   app.env,
+                                   opts.n_inputs,
+                                   opts.inputs,
+                                   inserter))) {
+    serd_tool_cleanup(app);
+    return st;
+  }
+
+  // Write the model to the output
+  const SerdSink* const target = serd_writer_sink(app.writer);
+  if (opts.collation) {
+    SerdCursor* const cursor = serd_model_begin_ordered(model, opts.order);
+
+    serd_env_write_prefixes(app.env, target);
+
+    for (const SerdStatement* statement = NULL;
+         !st && (statement = serd_cursor_get(cursor));
+         serd_cursor_advance(cursor)) {
+      st = serd_sink_write_statement(target, 0u, statement);
+    }
+
+    serd_cursor_free(cursor);
+  } else {
+    SerdCursor* const cursor = serd_model_begin(model);
+
+    serd_env_write_prefixes(app.env, target);
+
+    st = serd_describe_range(cursor, target, opts.flags);
+
+    serd_cursor_free(cursor);
+  }
+
+  if (!st) {
+    st = serd_writer_finish(app.writer);
+  }
+
+  const SerdStatus cst = serd_tool_cleanup(app);
+  return st ? st : cst;
+}
+
+/* Command-line interface (before setting up serd) */
+
+static SerdStatus
+parse_statement_order(const char* const string, SerdStatementOrder* const order)
+{
+  static const char* const strings[] = {"SPO",
+                                        "SOP",
+                                        "OPS",
+                                        "OSP",
+                                        "PSO",
+                                        "POS",
+                                        "GSPO",
+                                        "GSOP",
+                                        "GOPS",
+                                        "GOSP",
+                                        "GPSO",
+                                        "GPOS",
+                                        NULL};
+
+  for (unsigned i = 0; strings[i]; ++i) {
+    if (!strcmp(string, strings[i])) {
+      *order = (SerdStatementOrder)i;
+      return SERD_SUCCESS;
+    }
+  }
+
+  return SERD_ERR_BAD_ARG;
+}
+
+static int
+print_usage(const char* const name, const bool error)
+{
+  static const char* const description =
+    "Reorder RDF data by loading everything into a model then writing it.\n"
+    "INPUT can be a local filename, or \"-\" to read from standard input.\n\n"
+    "  -B BASE_URI   Base URI or path for resolving relative references.\n"
+    "  -I SYNTAX     Input syntax (turtle/ntriples/trig/nquads),\n"
+    "                or option (lax/variables/relative/global/generated).\n"
+    "  -O SYNTAX     Output syntax (empty/turtle/ntriples/nquads),\n"
+    "                or option (ascii/expanded/verbatim/terse/lax).\n"
+    "  -V            Display version information and exit.\n"
+    "  -b BYTES      I/O block size.\n"
+    "  -c COLLATION  An optional \"G\" then the letters \"SPO\" in any order.\n"
+    "  -h            Display this help and exit.\n"
+    "  -k BYTES      Parser stack size.\n"
+    "  -o FILENAME   Write output to FILENAME instead of stdout.\n";
+
+  FILE* const os = error ? stderr : stdout;
+  fprintf(os, "%s", error ? "\n" : "");
+  fprintf(os, "Usage: %s [OPTION]... INPUT...\n", name);
+  fprintf(os, "%s", description);
+  return error;
+}
+
+// Parse the option pointed to by `iter`, and advance it to the next one
+static SerdStatus
+parse_option(OptionIter* const iter, Options* const opts)
+{
+#define ARG_ERRORF(fmt, ...) \
+  fprintf(stderr, "%s: " fmt, iter->argv[0], __VA_ARGS__)
+
+  SerdStatus st = serd_parse_common_option(iter, &opts->common);
+  if (st != SERD_FAILURE) {
+    return st;
+  }
+
+  const char opt = iter->argv[iter->a][iter->f];
+  switch (opt) {
+  case 'R':
+    return serd_get_argument(iter, &opts->root_uri);
+
+  case 'V':
+    return serd_print_version("serd-sort");
+
+  case 'c':
+    if (!(st = serd_get_argument(iter, &opts->collation))) {
+      if ((st = parse_statement_order(opts->collation, &opts->order))) {
+        ARG_ERRORF("unknown collation \"%s\"\n", opts->collation);
+        return st;
+      }
+    }
+    return st;
+
+  case 'h':
+    print_usage(iter->argv[0], false);
+    return SERD_FAILURE;
+
+  case 's':
+    return serd_get_argument(iter, &opts->input_string);
+
+  default:
+    break;
+  }
+
+  ARG_ERRORF("invalid option -- '%c'\n", opt);
+  return SERD_ERR_BAD_ARG;
+
+#undef ARG_ERRORF
+}
+
+int
+main(const int argc, char* const* const argv)
+{
+  Options opts = {{"",
+                   NULL,
+                   4096u,
+                   1048576u,
+                   {SERD_SYNTAX_EMPTY, 0u, false},
+                   {SERD_SYNTAX_EMPTY, 0u, false}},
+                  "",
+                  NULL,
+                  NULL,
+                  NULL,
+                  0u,
+                  SERD_ORDER_SPO,
+                  0u};
+
+  // Parse all command line options (which must precede inputs)
+  SerdStatus st   = SERD_SUCCESS;
+  OptionIter iter = {argv, argc, 1, 1};
+  while (!serd_option_iter_is_end(iter)) {
+    if ((st = parse_option(&iter, &opts))) {
+      return (st == SERD_FAILURE) ? 0 : print_usage(argv[0], true);
+    }
+  }
+
+  // Every argument past the last option is an input
+  opts.inputs   = argv + iter.a;
+  opts.n_inputs = argc - iter.a;
+  if (opts.n_inputs + (bool)opts.input_string == 0) {
+    fprintf(stderr, "%s: missing input\n", argv[0]);
+    return print_usage(argv[0], true);
+  }
+
+  // Don't add prefixes to blank node labels if there is only one input
+  if (opts.n_inputs + (bool)opts.input_string == 1) {
+    opts.common.input.flags |= SERD_READ_GLOBAL;
+  }
+
+  return run(opts) > SERD_FAILURE;
+}