Provide a full output stream implementation for SerdBuffer

Essentially replaces serd_buffer_sink_finish() with serd_buffer_close(), which
makes writing to a buffer consistent with writing to a file or anything else.

11 files changed, 120 insertions, 79 deletions

diff --git a/include/serd/serd.h b/include/serd/serd.h
index daf903a2..c3b674b7 100644
--- a/include/serd/serd.h
+++ b/include/serd/serd.h
@@ -199,12 +199,6 @@ typedef struct {
    @}
 */
 
-/// A mutable buffer in memory
-typedef struct {
-  void* SERD_NULLABLE buf; ///< Buffer
-  size_t              len; ///< Size of buffer in bytes
-} SerdBuffer;
-
 /**
    Free memory allocated by Serd.
 
@@ -2387,6 +2381,52 @@ serd_reader_free(SerdReader* SERD_NULLABLE reader);
 
 /**
    @}
+   @defgroup serd_buffer Buffer
+
+   The #SerdBuffer type represents a writable area of memory with a known size.
+   An implementation of #SerdWriteFunc, #SerdStreamErrorFunc, and
+   #SerdStreamCloseFunc are provided which allow output to be written to a
+   buffer in memory instead of to a file as with `fwrite`, `ferror`, and
+   `fclose`.
+
+   @{
+*/
+
+/// A mutable buffer in memory
+typedef struct {
+  void* SERD_NULLABLE buf; ///< Buffer
+  size_t              len; ///< Size of buffer in bytes
+} SerdBuffer;
+
+/**
+   A function for writing to a buffer, resizing it if necessary.
+
+   This function can be used as a #SerdWriteFunc to write to a #SerdBuffer
+   which is resized as necessary with realloc().  The `stream` parameter must
+   point to an initialized #SerdBuffer.
+
+   Note that when writing a string, the string in the buffer will not be
+   null-terminated until serd_buffer_close() is called.
+*/
+SERD_API
+size_t
+serd_buffer_write(const void* SERD_NONNULL buf,
+                  size_t                   size,
+                  size_t                   nmemb,
+                  void* SERD_NONNULL       stream);
+
+/**
+   Close the buffer for writing.
+
+   This writes a terminating null byte, so the contents of the buffer are safe
+   to read as a string after this call.
+*/
+SERD_API
+int
+serd_buffer_close(void* SERD_NONNULL stream);
+
+/**
+   @}
    @defgroup serd_byte_sink Byte Sink
    @{
 */
@@ -2556,31 +2596,6 @@ const SerdSink* SERD_NONNULL
 serd_writer_sink(SerdWriter* SERD_NONNULL writer);
 
 /**
-   A convenience sink function for writing to a string.
-
-   This function can be used as a SerdSink to write to a SerdBuffer which is
-   resized as necessary with realloc().  The `stream` parameter must point to
-   an initialized SerdBuffer.  When the write is finished, the string should be
-   retrieved with serd_buffer_sink_finish().
-*/
-SERD_API
-size_t
-serd_buffer_sink(const void* SERD_NONNULL buf,
-                 size_t                   size,
-                 size_t                   nmemb,
-                 void* SERD_NONNULL       stream);
-
-/**
-   Finish writing to a buffer with serd_buffer_sink().
-
-   The returned string is the result of the serialisation, which is null
-   terminated (by this function) and owned by the caller.
-*/
-SERD_API
-char* SERD_NONNULL
-serd_buffer_sink_finish(SerdBuffer* SERD_NONNULL stream);
-
-/**
    Set the current output base URI, and emit a directive if applicable.
 
    Note this function can be safely casted to SerdBaseSink.
diff --git a/meson.build b/meson.build
index f75ce560..c1713ce6 100644
--- a/meson.build
+++ b/meson.build
@@ -86,6 +86,7 @@ c_header_files = files(c_headers)
 c_header = files('include/serd/serd.h')
 
 sources = [
+  'src/buffer.c',
   'src/byte_sink.c',
   'src/byte_source.c',
   'src/canon.c',
diff --git a/src/buffer.c b/src/buffer.c
new file mode 100644
index 00000000..85ec09de
--- /dev/null
+++ b/src/buffer.c
@@ -0,0 +1,52 @@
+/*
+  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 "serd/serd.h"
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+size_t
+serd_buffer_write(const void* const buf,
+                  const size_t      size,
+                  const size_t      nmemb,
+                  void* const       stream)
+{
+  assert(buf);
+  assert(stream);
+
+  SerdBuffer* const buffer  = (SerdBuffer*)stream;
+  const size_t      n_bytes = size * nmemb;
+
+  char* const new_buf = (char*)realloc(buffer->buf, buffer->len + n_bytes);
+  if (new_buf) {
+    memcpy(new_buf + buffer->len, buf, n_bytes);
+    buffer->buf = new_buf;
+    buffer->len += nmemb;
+  }
+
+  return new_buf ? nmemb : 0;
+}
+
+int
+serd_buffer_close(void* const stream)
+{
+  serd_buffer_write("", 1, 1, stream); // Write null terminator
+
+  return 0;
+}
diff --git a/src/byte_sink.c b/src/byte_sink.c
index febd11cd..b5b4039e 100644
--- a/src/byte_sink.c
+++ b/src/byte_sink.c
@@ -30,21 +30,13 @@
 #  include <fcntl.h>
 #endif
 
-static int
-close_buffer(void* const stream)
-{
-  serd_buffer_sink("", 1, 1, stream); // Write null terminator
-
-  return 0;
-}
-
 SerdByteSink*
 serd_byte_sink_new_buffer(SerdBuffer* const buffer)
 {
   assert(buffer);
 
   return serd_byte_sink_new_function(
-    serd_buffer_sink, close_buffer, buffer, 1u);
+    serd_buffer_write, serd_buffer_close, buffer, 1u);
 }
 
 SerdByteSink*
diff --git a/src/uri.c b/src/uri.c
index 1862c280..bbd53ca3 100644
--- a/src/uri.c
+++ b/src/uri.c
@@ -60,22 +60,23 @@ serd_parse_file_uri(const char* const uri, char** const hostname)
   for (const char* s = path; *s; ++s) {
     if (*s == '%') {
       if (*(s + 1) == '%') {
-        serd_buffer_sink("%", 1, 1, &buffer);
+        serd_buffer_write("%", 1, 1, &buffer);
         ++s;
       } else if (is_hexdig(*(s + 1)) && is_hexdig(*(s + 2))) {
         const char code[3] = {*(s + 1), *(s + 2), 0};
         const char c       = (char)strtoul(code, NULL, 16);
-        serd_buffer_sink(&c, 1, 1, &buffer);
+        serd_buffer_write(&c, 1, 1, &buffer);
         s += 2;
       } else {
         s += 2; // Junk escape, ignore
       }
     } else {
-      serd_buffer_sink(s, 1, 1, &buffer);
+      serd_buffer_write(s, 1, 1, &buffer);
     }
   }
 
-  return serd_buffer_sink_finish(&buffer);
+  serd_buffer_close(&buffer);
+  return (char*)buffer.buf;
 }
 
 /// RFC3986: scheme ::= ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
diff --git a/src/writer.c b/src/writer.c
index b7814158..305c72e1 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -1436,31 +1436,3 @@ serd_writer_sink(SerdWriter* writer)
   assert(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(buf);
-  assert(size == 1);
-  assert(stream);
-
-  (void)size;
-
-  SerdBuffer* buffer = (SerdBuffer*)stream;
-  buffer->buf        = (char*)realloc(buffer->buf, buffer->len + nmemb);
-  memcpy((uint8_t*)buffer->buf + buffer->len, buf, nmemb);
-  buffer->len += nmemb;
-  return nmemb;
-}
-
-char*
-serd_buffer_sink_finish(SerdBuffer* const stream)
-{
-  assert(stream);
-
-  serd_buffer_sink("", 1, 1, stream);
-  return (char*)stream->buf;
-}
diff --git a/test/test_reader_writer.c b/test/test_reader_writer.c
index 1bad22cd..b8afd649 100644
--- a/test/test_reader_writer.c
+++ b/test/test_reader_writer.c
@@ -121,7 +121,7 @@ test_writer(const char* const path)
 
   serd_writer_free(writer);
   serd_byte_sink_free(byte_sink);
-  char* out = serd_buffer_sink_finish(&buffer);
+  char* out = (char*)buffer.buf;
 
   assert(!strcmp(out, "@base <http://example.org/base> .\n"));
   serd_free(out);
diff --git a/test/test_terse_write.c b/test/test_terse_write.c
index 59227332..aeb264ea 100644
--- a/test/test_terse_write.c
+++ b/test/test_terse_write.c
@@ -29,7 +29,7 @@ static void
 check_output(SerdWriter* writer, SerdBuffer* buffer, const char* expected)
 {
   serd_writer_finish(writer);
-  serd_buffer_sink_finish(buffer);
+  serd_buffer_close(buffer);
 
   const char* output = (const char*)buffer->buf;
 
@@ -98,7 +98,6 @@ test(void)
   serd_sink_write(sink, 0, l2, rdf_rest, rdf_nil, NULL);
   check_output(writer, &buffer, "[]\n\trdf:value ( \"s1\" \"s2\" ) .\n");
 
-  serd_buffer_sink_finish(&buffer);
   serd_writer_free(writer);
   serd_byte_sink_free(byte_sink);
   serd_nodes_free(nodes);
diff --git a/test/test_writer.c b/test/test_writer.c
index 89531eee..83d4087c 100644
--- a/test/test_writer.c
+++ b/test/test_writer.c
@@ -83,14 +83,15 @@ test_write_long_literal(void)
   serd_writer_free(writer);
   serd_byte_sink_free(byte_sink);
   serd_env_free(env);
+  serd_buffer_close(&buffer);
 
-  char* out = serd_buffer_sink_finish(&buffer);
+  char* out = (char*)buffer.buf;
 
   static const char* const expected =
     "<http://example.org/s>\n"
     "\t<http://example.org/p> \"\"\"hello \"\"\\\"world\"\"\\\"!\"\"\" .\n";
 
-  assert(!strcmp((char*)out, expected));
+  assert(!strcmp(out, expected));
   serd_free(out);
 
   serd_world_free(world);
@@ -369,10 +370,11 @@ check_pname_escape(const char* const lname, const char* const expected)
   serd_writer_free(writer);
   serd_byte_sink_free(byte_sink);
   serd_env_free(env);
+  serd_buffer_close(&buffer);
 
-  char* out = serd_buffer_sink_finish(&buffer);
+  char* out = (char*)buffer.buf;
 
-  assert(!strcmp((char*)out, expected));
+  assert(!strcmp(out, expected));
   serd_free(out);
 
   free(uri);
diff --git a/tools/serd-pipe.c b/tools/serd-pipe.c
index 25efb54f..57392c8a 100644
--- a/tools/serd-pipe.c
+++ b/tools/serd-pipe.c
@@ -83,10 +83,12 @@ run(const Options opts)
       (st = serd_read_inputs(
          app.world, opts.common, app.env, opts.n_inputs, opts.inputs, sink)) ||
       (st = serd_writer_finish(app.writer))) {
+    serd_sink_free(canon);
     serd_tool_cleanup(app);
     return st;
   }
 
+  serd_sink_free(canon);
   return serd_tool_cleanup(app);
 }
 
diff --git a/tools/serd-sort.c b/tools/serd-sort.c
index 5e71e95e..bbdfa164 100644
--- a/tools/serd-sort.c
+++ b/tools/serd-sort.c
@@ -95,6 +95,8 @@ run(const Options opts)
                                    opts.n_inputs,
                                    opts.inputs,
                                    inserter))) {
+    serd_sink_free(inserter);
+    serd_model_free(model);
     serd_tool_cleanup(app);
     return st;
   }
@@ -127,6 +129,9 @@ run(const Options opts)
     st = serd_writer_finish(app.writer);
   }
 
+  serd_sink_free(inserter);
+  serd_model_free(model);
+
   const SerdStatus cst = serd_tool_cleanup(app);
   return st ? st : cst;
 }