From df82b5a63f16b45e3a765f86264f1ff875887250 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Sat, 8 Feb 2020 01:02:08 +0100
Subject: absurd buffering test

---
 stream/stream_file.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 3 deletions(-)

diff --git a/stream/stream_file.c b/stream/stream_file.c
index a79ef0e913..b2c4d1d833 100644
--- a/stream/stream_file.c
+++ b/stream/stream_file.c
@@ -26,6 +26,8 @@
 #include <unistd.h>
 #include <errno.h>
 
+#include <pthread.h>
+
 #ifndef __MINGW32__
 #include <poll.h>
 #endif
@@ -35,6 +37,7 @@
 #include "common/common.h"
 #include "common/msg.h"
 #include "misc/thread_tools.h"
+#include "misc/ring.h"
 #include "stream.h"
 #include "options/m_option.h"
 #include "options/path.h"
@@ -66,21 +69,63 @@ struct priv {
     bool appending;
     int64_t orig_size;
     struct mp_cancel *cancel;
+    struct mp_ring *ring;
+    pthread_t thread;
+    pthread_mutex_t lock;
+    pthread_cond_t wakeup;
+    bool read_ok, in_io, eof, terminate;
+    int64_t size;
 };
 
 // Total timeout = RETRY_TIMEOUT * MAX_RETRIES
 #define RETRY_TIMEOUT 0.2
 #define MAX_RETRIES 10
 
+static void stop_io(stream_t *s)
+{
+    struct priv *p = s->priv;
+
+    pthread_mutex_lock(&p->lock);
+    p->read_ok = false;
+    while (p->in_io)
+        pthread_cond_wait(&p->wakeup, &p->lock);
+    pthread_mutex_unlock(&p->lock);
+}
+
 static int64_t get_size(stream_t *s)
 {
     struct priv *p = s->priv;
-    off_t size = lseek(p->fd, 0, SEEK_END);
-    lseek(p->fd, s->pos, SEEK_SET);
-    return size == (off_t)-1 ? -1 : size;
+    if (!p->size) {
+        stop_io(s);
+        off_t size = lseek(p->fd, 0, SEEK_END);
+        lseek(p->fd, s->pos, SEEK_SET);
+        p->size = size == (off_t)-1 ? -1 : size;
+    }
+    return p->size;
 }
 
 static int fill_buffer(stream_t *s, void *buffer, int max_len)
+{
+    struct priv *p = s->priv;
+
+    int res = 0;
+    pthread_mutex_lock(&p->lock);
+    while (1) {
+        int r = mp_ring_buffered(p->ring);
+        if (r || p->eof) {
+            res = mp_ring_read(p->ring, buffer, max_len);
+            break;
+        }
+        p->read_ok = true;
+        pthread_cond_broadcast(&p->wakeup);
+        pthread_cond_wait(&p->wakeup, &p->lock);
+    }
+    pthread_mutex_unlock(&p->lock);
+
+    return res;
+}
+
+static int real_fill_buffer(stream_t *s, void *buffer, int max_len)
 {
     struct priv *p = s->priv;
 
@@ -120,21 +165,61 @@ static int fill_buffer(stream_t *s, void *buffer, int max_len)
     return 0;
 }
 
+static void *read_thread(void *arg)
+{
+    stream_t *s = arg;
+    struct priv *p = s->priv;
+
+    pthread_mutex_lock(&p->lock);
+    while (!p->terminate) {
+        int a = mp_ring_available(p->ring);
+        if (p->read_ok && a >= 64 * 1024) {
+            p->in_io = true;
+            pthread_mutex_unlock(&p->lock);
+            uint8_t buf[64 * 1024];
+            int r = real_fill_buffer(s, buf, sizeof(buf));
+            r = MPMAX(r, 0);
+            pthread_mutex_lock(&p->lock);
+            p->in_io = false;
+            mp_ring_write(p->ring, buf, r);
+            p->eof = !r;
+            pthread_cond_broadcast(&p->wakeup);
+        } else {
+            pthread_cond_wait(&p->wakeup, &p->lock);
+        }
+    }
+    pthread_mutex_unlock(&p->lock);
+
+    return NULL;
+}
+
 static int write_buffer(stream_t *s, void *buffer, int len)
 {
     struct priv *p = s->priv;
+    stop_io(s);
     return write(p->fd, buffer, len);
 }
 
 static int seek(stream_t *s, int64_t newpos)
 {
     struct priv *p = s->priv;
+    stop_io(s);
+    pthread_mutex_lock(&p->lock);
+    mp_ring_reset(p->ring);
+    p->eof = false;
+    pthread_mutex_unlock(&p->lock);
     return lseek(p->fd, newpos, SEEK_SET) != (off_t)-1;
 }
 
 static void s_close(stream_t *s)
 {
     struct priv *p = s->priv;
+    stop_io(s);
+    pthread_mutex_lock(&p->lock);
+    p->terminate = true;
+    pthread_cond_broadcast(&p->wakeup);
+    pthread_mutex_unlock(&p->lock);
+    pthread_join(p->thread, NULL);
     if (p->close)
         close(p->fd);
 }
@@ -340,6 +425,13 @@ static int open_f(stream_t *stream)
     if (stream->cancel)
         mp_cancel_set_parent(p->cancel, stream->cancel);
 
+    pthread_mutex_init(&p->lock, NULL);
+    pthread_cond_init(&p->wakeup, NULL);
+    p->ring = mp_ring_new(stream, 2 * 64 * 1024);
+    int r = pthread_create(&p->thread, NULL, read_thread, stream);
+    if (r)
+        return -1;
+
     return STREAM_OK;
 }
 
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