http: Add support for zstd compression

Signed-off-by: Andrew Clayton <[email protected]>

Author: ac000

src/nxt_http_compression.c

@@ -31,6 +31,9 @@ enum nxt_http_comp_scheme_e {
     NXT_HTTP_COMP_SCHEME_DEFLATE,
     NXT_HTTP_COMP_SCHEME_GZIP,
 #endif
+#if NXT_HAVE_ZSTD
+    NXT_HTTP_COMP_SCHEME_ZSTD,
+#endif
 
     /* keep last */
     NXT_HTTP_COMP_SCHEME_UNKNOWN
@@ -108,6 +111,15 @@ static const nxt_http_comp_type_t  nxt_http_comp_compressors[] = {
         .comp_min   = NXT_HTTP_COMP_ZLIB_COMP_MIN,
         .comp_max   = NXT_HTTP_COMP_ZLIB_COMP_MAX,
         .cops       = &nxt_http_comp_gzip_ops,
+#endif
+#if NXT_HAVE_ZSTD
+    }, {
+        .token      = nxt_string("zstd"),
+        .scheme     = NXT_HTTP_COMP_SCHEME_ZSTD,
+        .def_compr  = NXT_HTTP_COMP_ZSTD_DEFAULT_LEVEL,
+        .comp_min   = NXT_HTTP_COMP_ZSTD_COMP_MIN,
+        .comp_max   = NXT_HTTP_COMP_ZSTD_COMP_MAX,
+        .cops       = &nxt_http_comp_zstd_ops,
 #endif
     },
 };

src/nxt_http_compression.h

@@ -16,6 +16,10 @@
 #include <zlib.h>
 #endif
 
+#if NXT_HAVE_ZSTD
+#include <zstd.h>
+#endif
+
 #include <nxt_main.h>
 #include <nxt_router.h>
 #include <nxt_string.h>
@@ -27,6 +31,11 @@
 #define NXT_HTTP_COMP_ZLIB_COMP_MIN            Z_DEFAULT_COMPRESSION
 #define NXT_HTTP_COMP_ZLIB_COMP_MAX            Z_BEST_COMPRESSION
 #endif
+#if NXT_HAVE_ZSTD
+#define NXT_HTTP_COMP_ZSTD_DEFAULT_LEVEL       ZSTD_CLEVEL_DEFAULT
+#define NXT_HTTP_COMP_ZSTD_COMP_MIN            (-7)
+#define NXT_HTTP_COMP_ZSTD_COMP_MAX            22
+#endif
 
 
 typedef struct nxt_http_comp_compressor_ctx_s  nxt_http_comp_compressor_ctx_t;
@@ -38,6 +47,9 @@ struct nxt_http_comp_compressor_ctx_s {
     union {
 #if NXT_HAVE_ZLIB
         z_stream zlib_ctx;
+#endif
+#if NXT_HAVE_ZSTD
+        ZSTD_CStream *zstd_ctx;
 #endif
     };
 };
@@ -57,6 +69,10 @@ extern const nxt_http_comp_operations_t  nxt_http_comp_deflate_ops;
 extern const nxt_http_comp_operations_t  nxt_http_comp_gzip_ops;
 #endif
 
+#if NXT_HAVE_ZSTD
+extern const nxt_http_comp_operations_t  nxt_http_comp_zstd_ops;
+#endif
+
 
 extern bool nxt_http_comp_wants_compression(void);
 extern bool nxt_http_comp_compressor_is_valid(const nxt_str_t *token);

src/nxt_zstd.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) Andrew Clayton
+ * Copyright (C) F5, Inc.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <zstd.h>
+
+#include "nxt_http_compression.h"
+
+
+static int
+nxt_zstd_init(nxt_http_comp_compressor_ctx_t *ctx)
+{
+    ZSTD_CStream  **zstd = &ctx->zstd_ctx;
+
+    *zstd = ZSTD_createCStream();
+    if (*zstd == NULL) {
+        return -1;
+    }
+    ZSTD_initCStream(*zstd, ctx->level);
+
+    return 0;
+}
+
+
+static size_t
+nxt_zstd_bound(const nxt_http_comp_compressor_ctx_t *ctx, size_t in_len)
+{
+    return ZSTD_compressBound(in_len);
+}
+
+
+static ssize_t
+nxt_zstd_compress(nxt_http_comp_compressor_ctx_t *ctx, const uint8_t *in_buf,
+                  size_t in_len, uint8_t *out_buf, size_t out_len, bool last)
+{
+    size_t          ret;
+    ZSTD_CStream    *zstd = ctx->zstd_ctx;
+    ZSTD_inBuffer   zinb = { .src = in_buf, .size = in_len };
+    ZSTD_outBuffer  zoutb = { .dst = out_buf, .size = out_len };
+
+    ret = ZSTD_compressStream(zstd, &zoutb, &zinb);
+
+    if (zinb.pos < zinb.size) {
+        ret = ZSTD_flushStream(zstd, &zoutb);
+    }
+
+    if (last) {
+        ret = ZSTD_endStream(zstd, &zoutb);
+        ZSTD_freeCStream(zstd);
+    }
+
+    if (ZSTD_isError(ret)) {
+        return -1;
+    }
+
+    return zoutb.pos;
+}
+
+
+const nxt_http_comp_operations_t  nxt_http_comp_zstd_ops = {
+    .init               = nxt_zstd_init,
+    .bound              = nxt_zstd_bound,
+    .deflate            = nxt_zstd_compress,
+};