From 3f083851446d5d3fa012800cdee5be23bd5541b7 Mon Sep 17 00:00:00 2001
From: Roman Arutyunyan <arut@qip.ru>
Date: Wed, 12 Sep 2012 14:58:31 +0400
Subject: [PATCH] added common evaluation code

---
 ngx_rtmp_eval.c | 184 ++++++++++++++++++++++++++++++++++++++++++++++++
 ngx_rtmp_eval.h |  37 ++++++++++
 2 files changed, 221 insertions(+)
 create mode 100644 ngx_rtmp_eval.c
 create mode 100644 ngx_rtmp_eval.h

diff --git a/ngx_rtmp_eval.c b/ngx_rtmp_eval.c
new file mode 100644
index 0000000..f940e02
--- /dev/null
+++ b/ngx_rtmp_eval.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2012 Roman Arutyunyan
+ */
+
+
+#include "ngx_rtmp_eval.h"
+
+
+#define NGX_RTMP_EVAL_BUFLEN    16
+
+
+static void
+ngx_rtmp_eval_session_str(ngx_rtmp_session_t *s, ngx_rtmp_eval_t *e,
+                      ngx_str_t *ret)
+{
+    *ret = *(ngx_str_t *) ((u_char *) s + e->offset);
+}
+
+
+static void
+ngx_rtmp_eval_connection_str(ngx_rtmp_session_t *s, ngx_rtmp_eval_t *e,
+                      ngx_str_t *ret)
+{
+    *ret = *(ngx_str_t *) ((u_char *) s->connection + e->offset);
+}
+
+
+ngx_rtmp_eval_t ngx_rtmp_eval_session[] = {
+
+    { ngx_string("app"),
+      ngx_rtmp_eval_session_str,
+      offsetof(ngx_rtmp_session_t, app) },
+
+    { ngx_string("flashver"),
+      ngx_rtmp_eval_session_str,
+      offsetof(ngx_rtmp_session_t, flashver) },
+
+    { ngx_string("swfurl"),
+      ngx_rtmp_eval_session_str,
+      offsetof(ngx_rtmp_session_t, swf_url) },
+
+    { ngx_string("tcurl"),
+      ngx_rtmp_eval_session_str,
+      offsetof(ngx_rtmp_session_t, tc_url) },
+
+    { ngx_string("pageurl"),
+      ngx_rtmp_eval_session_str,
+      offsetof(ngx_rtmp_session_t, page_url) },
+
+    { ngx_string("addr"),
+      ngx_rtmp_eval_connection_str,
+      offsetof(ngx_connection_t, addr_text) },
+
+    ngx_rtmp_null_eval
+};
+
+
+static void
+ngx_rtmp_eval_append(ngx_rtmp_session_t *s, ngx_buf_t *b,
+                     void *data, size_t len)
+{
+    size_t  buf_len;
+
+    if (b->last + len > b->end) {
+        buf_len = 2 * (b->last - b->pos) + len;
+
+        b->start = ngx_palloc(s->connection->pool, buf_len);
+        if (b->start == NULL) {
+            return;
+        }
+
+        b->last = ngx_cpymem(b->start, b->pos, b->last - b->pos);
+        b->pos = b->start;
+        b->end = b->start + buf_len;
+    }
+
+    b->last = ngx_cpymem(b->last, data, len);
+}
+
+
+static void
+ngx_rtmp_eval_append_var(ngx_rtmp_session_t *s, ngx_buf_t *b,
+                         ngx_rtmp_eval_t *e, ngx_str_t *name)
+{
+    ngx_uint_t  k;
+    ngx_str_t   v;
+
+    for (k = 0; e->handler; ++k, ++e) {
+        if (e->name.len == name->len &&
+            ngx_memcmp(e->name.data, name->data, name->len) == 0)
+        {
+            e->handler(s, e, &v);
+            ngx_rtmp_eval_append(s, b, v.data, v.len);
+        }
+    }
+}
+
+
+ngx_int_t
+ngx_rtmp_eval(ngx_rtmp_session_t *s, ngx_str_t *in, ngx_rtmp_eval_t *e,
+              ngx_str_t *out)
+{
+    u_char      c, *p;;
+    ngx_str_t   name;
+    ngx_buf_t   b;
+    ngx_uint_t  n;
+
+    enum {
+        NORMAL,
+        ESCAPE,
+        NAME,
+        SNAME
+    } state = NORMAL;
+
+    b.pos = b.last = b.start = ngx_palloc(s->connection->pool,
+                                             NGX_RTMP_EVAL_BUFLEN);
+    if (b.pos == NULL) {
+        return NGX_ERROR;
+    }
+
+    b.end = b.pos + NGX_RTMP_EVAL_BUFLEN;
+
+    for (n = 0; n < in->len; ++n) {
+        p = &in->data[n];
+        c = *p;
+
+        switch (state) {
+            case SNAME:
+                if (c != '}') {
+                    continue;
+                }
+
+                name.len = p - name.data;
+                ngx_rtmp_eval_append_var(s, &b, e, &name);
+
+                state = NORMAL;
+
+                continue;
+
+            case NAME:
+                if (c == '{' && name.data == p) {
+                    ++name.data;
+                    state = SNAME;
+                    continue;
+                }
+                if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
+                    continue;
+                }
+
+                name.len = p - name.data;
+                ngx_rtmp_eval_append_var(s, &b, e, &name);
+
+            case NORMAL:
+                switch (c) {
+                    case '$':
+                        name.data = p + 1;
+                        state = NAME;
+                        continue;
+                    case '\\':
+                        state = ESCAPE;
+                        continue;
+                }
+
+            case ESCAPE:
+                ngx_rtmp_eval_append(s, &b, &c, 1);
+                state = NORMAL;
+                break;
+
+        }
+    }
+
+    if (state == NAME) {
+        name.len = p - name.data;
+        ngx_rtmp_eval_append_var(s, &b, e, &name);
+    }
+
+    c = 0;
+    ngx_rtmp_eval_append(s, &b, &c, 1);
+
+    out->data = b.pos;
+    out->len  = b.last - b.pos - 1;
+
+    return NGX_OK;
+}
diff --git a/ngx_rtmp_eval.h b/ngx_rtmp_eval.h
new file mode 100644
index 0000000..fae2502
--- /dev/null
+++ b/ngx_rtmp_eval.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2012 Roman Arutyunyan
+ */
+
+
+#ifndef _NGX_RTMP_EVAL_H_INCLUDED_
+#define _NGX_RTMP_EVAL_H_INCLUDED_
+
+#include "ngx_rtmp.h"
+
+
+typedef struct ngx_rtmp_eval_s ngx_rtmp_eval_t;
+
+
+typedef void (* ngx_rtmp_eval_pt)(ngx_rtmp_session_t *s, ngx_rtmp_eval_t *e,
+                                  ngx_str_t *ret);
+
+
+struct ngx_rtmp_eval_s {
+    ngx_str_t               name;
+    ngx_rtmp_eval_pt        handler;
+    ngx_uint_t              offset;
+};
+
+
+#define ngx_rtmp_null_eval  { ngx_null_string, NULL, 0 }
+
+
+/* standard session eval variables */
+extern ngx_rtmp_eval_t      ngx_rtmp_eval_session[];
+
+
+ngx_int_t ngx_rtmp_eval(ngx_rtmp_session_t *s, ngx_str_t *in,
+          ngx_rtmp_eval_t *e, ngx_str_t *out);
+
+
+#endif /* _NGX_RTMP_EVAL_H_INCLUDED_ */