From f7b993d5aff1274e010d45304b12109f6de7e120 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sun, 28 Jun 2020 19:46:47 +0200
Subject: WIP: Make Writer always write to a ByteSink

---
 src/byte_sink.c | 107 ++++++++++++++++++++++++++++++++------------------------
 1 file changed, 62 insertions(+), 45 deletions(-)

(limited to 'src/byte_sink.c')

diff --git a/src/byte_sink.c b/src/byte_sink.c
index a90f503d..7aaec065 100644
--- a/src/byte_sink.c
+++ b/src/byte_sink.c
@@ -14,32 +14,48 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include "macros.h"
+#define _POSIX_C_SOURCE 200809L /* for posix_fadvise and fileno */
+
+#include "byte_sink.h"
+
+#include "serd_config.h"
 #include "system.h"
 
 #include "serd/serd.h"
 
-#include <assert.h>
 #include <stddef.h>
+#include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 
-struct SerdByteSinkImpl {
-  SerdWriteFunc sink;
-  void*         stream;
-  char*         buf;
-  size_t        size;
-  size_t        block_size;
-};
+#if defined(USE_POSIX_FADVISE) || defined(USE_FILENO)
+#  include <fcntl.h>
+#endif
 
 SerdByteSink*
-serd_byte_sink_new(SerdWriteFunc write_func, void* stream, size_t block_size)
+serd_byte_sink_new_buffer(SerdBuffer* const buffer)
 {
   SerdByteSink* sink = (SerdByteSink*)calloc(1, sizeof(SerdByteSink));
 
-  sink->sink       = write_func;
+  sink->write_func = serd_buffer_sink;
+  sink->stream     = buffer;
+  sink->block_size = 1;
+  sink->type       = TO_BUFFER;
+
+  return sink;
+}
+
+static SerdByteSink*
+serd_byte_sink_new_internal(const SerdWriteFunc    write_func,
+                            void* const            stream,
+                            const size_t           block_size,
+                            const SerdByteSinkType type)
+{
+  SerdByteSink* sink = (SerdByteSink*)calloc(1, sizeof(SerdByteSink));
+
+  sink->write_func = write_func;
   sink->stream     = stream;
   sink->block_size = block_size;
+  sink->type       = type;
 
   if (block_size > 1) {
     sink->buf = (char*)serd_allocate_buffer(block_size);
@@ -48,58 +64,59 @@ serd_byte_sink_new(SerdWriteFunc write_func, void* stream, size_t block_size)
   return sink;
 }
 
-size_t
-serd_byte_sink_write(const void*   buf,
-                     size_t        size,
-                     size_t        nmemb,
-                     SerdByteSink* sink)
+SerdByteSink*
+serd_byte_sink_new_filename(const char* const path, const size_t block_size)
 {
-  assert(size == 1);
-  (void)size;
-
-  if (nmemb == 0) {
-    return 0;
+  FILE* const file = fopen(path, "wb");
+  if (!file) {
+    return NULL;
   }
 
-  if (sink->block_size == 1) {
-    return sink->sink(buf, 1, nmemb, sink->stream);
-  }
+#if defined(USE_POSIX_FADVISE) && defined(USE_FILENO)
+  posix_fadvise(fileno(file), 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
 
-  const size_t orig_len = nmemb;
-  while (nmemb) {
-    const size_t space = sink->block_size - sink->size;
-    const size_t n     = MIN(space, nmemb);
-
-    // Write as much as possible into the remaining buffer space
-    memcpy(sink->buf + sink->size, buf, n);
-    sink->size += n;
-    buf = (const char*)buf + n;
-    nmemb -= n;
-
-    // Flush page if buffer is full
-    if (sink->size == sink->block_size) {
-      sink->sink(sink->buf, 1, sink->block_size, sink->stream);
-      sink->size = 0;
-    }
-  }
+  return serd_byte_sink_new_internal(
+    (SerdWriteFunc)fwrite, file, block_size, TO_FILENAME);
+}
 
-  return orig_len;
+SerdByteSink*
+serd_byte_sink_new_function(const SerdWriteFunc write_func,
+                            void* const         stream,
+                            const size_t        block_size)
+{
+  return serd_byte_sink_new_internal(
+    write_func, stream, block_size, TO_FUNCTION);
 }
 
 void
 serd_byte_sink_flush(SerdByteSink* sink)
 {
   if (sink->block_size > 1 && sink->size > 0) {
-    sink->sink(sink->buf, 1, sink->size, sink->stream);
+    sink->write_func(sink->buf, 1, sink->size, sink->stream);
     sink->size = 0;
   }
 }
 
+SerdStatus
+serd_byte_sink_close(SerdByteSink* sink)
+{
+  serd_byte_sink_flush(sink);
+
+  if (sink->type == TO_FILENAME && sink->stream) {
+    const int st = fclose((FILE*)sink->stream);
+    sink->stream = NULL;
+    return st ? SERD_ERR_UNKNOWN : SERD_SUCCESS;
+  }
+
+  return SERD_SUCCESS;
+}
+
 void
 serd_byte_sink_free(SerdByteSink* sink)
 {
   if (sink) {
-    serd_byte_sink_flush(sink);
+    serd_byte_sink_close(sink);
     free(sink->buf);
     free(sink);
   }
-- 
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