[PATCH 10/12] record: Add zlib filter class

[Sebastian Huber]

Update #3904.
---
 trace/record/client.h              | 24 ++++++++++++
 trace/record/record-filter-zlib.cc | 77 ++++++++++++++++++++++++++++++++++++++
 trace/wscript                      |  5 +++
 3 files changed, 106 insertions(+)
 create mode 100644 trace/record/record-filter-zlib.cc

diff --git a/trace/record/client.h b/trace/record/client.h
index b4a0c26..62ffdb5 100644
--- a/trace/record/client.h
+++ b/trace/record/client.h
@@ -42,6 +42,11 @@
 #include <stdexcept>
 #include <string>
 #include <utility>
+#include <vector>
+
+#ifdef HAVE_ZLIB_H
+#include <zlib.h>
+#endif
 
 class ErrnoException : public std::runtime_error {
  public:
@@ -132,6 +137,25 @@ class Base64Filter : public Filter {
   bool DecodeChar(int c, char **target);
 };
 
+#ifdef HAVE_ZLIB_H
+class ZlibFilter : public Filter {
+ public:
+  ZlibFilter();
+
+  ZlibFilter(const ZlibFilter&) = default;
+
+  ZlibFilter& operator=(const ZlibFilter&) = default;
+
+  virtual ~ZlibFilter();
+
+  virtual bool Run(void** buf, size_t* n);
+
+ private:
+  z_stream stream_;
+  std::vector<Bytef> buffer_;
+};
+#endif
+
 class Client {
  public:
   Client() = default;
diff --git a/trace/record/record-filter-zlib.cc b/trace/record/record-filter-zlib.cc
new file mode 100644
index 0000000..87b2cfe
--- /dev/null
+++ b/trace/record/record-filter-zlib.cc
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/*
+ * Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_ZLIB_H
+
+#include "client.h"
+
+ZlibFilter::ZlibFilter() : buffer_(65536)
+{
+  inflateInit(&stream_);
+}
+
+ZlibFilter::~ZlibFilter()
+{
+  inflateEnd(&stream_);
+}
+
+bool ZlibFilter::Run(void** buf, size_t* n) {
+  stream_.next_in = static_cast<unsigned char*>(*buf);
+  stream_.avail_in = *n;
+  stream_.next_out = &buffer_[0];
+  size_t avail_out = 0;
+  size_t buffer_size = buffer_.size();
+  size_t chunk_size = buffer_size;
+  stream_.avail_out = buffer_size;
+
+  while (true) {
+    int err = inflate(&stream_, Z_NO_FLUSH);
+    if (err != Z_OK && err != Z_STREAM_END) {
+      return false;
+    }
+
+    if (stream_.avail_in > 0) {
+      chunk_size = buffer_size;
+      buffer_size *= 2;
+      buffer_.resize(buffer_size);
+      stream_.next_out = reinterpret_cast<Bytef*>(&buffer_[chunk_size]);
+      stream_.avail_out = chunk_size;
+      avail_out += chunk_size;
+      continue;
+    }
+
+    *buf = &buffer_[0];
+    *n = avail_out + chunk_size - stream_.avail_out;
+    return true;
+  }
+}
+
+#endif  // HAVE_ZLIB_H
diff --git a/trace/wscript b/trace/wscript
index 7e35f74..656f92b 100644
--- a/trace/wscript
+++ b/trace/wscript
@@ -42,6 +42,8 @@ def configure(conf):
         pass
     if conf.check_cxx(lib = 'LLVM', mandatory=False):
         conf.check(header_name='llvm/DebugInfo/Symbolize/Symbolize.h', features='cxx', mandatory=False)
+    if conf.check(header_name='zlib.h', features='cxx', mandatory=False):
+        conf.check_cxx(lib = 'z')
     conf.check_cxx(lib = 'ws2_32', mandatory=False)
     conf.write_config_header('config.h')
 
@@ -65,6 +67,8 @@ def build(bld):
         conf['lib'].extend(bld.env.LIB_WS2_32)
     if bld.env.LIB_LLVM:
         conf['lib'].extend(bld.env.LIB_LLVM)
+    if bld.env.LIB_Z:
+        conf['lib'].extend(bld.env.LIB_Z)
 
     #
     # The list of defines
@@ -81,6 +85,7 @@ def build(bld):
                           'record/record-text.c',
                           'record/record-client-base.cc',
                           'record/record-filter-base64.cc',
+                          'record/record-filter-zlib.cc',
                           'record/record-main-lttng.cc',
                           'record/inih/ini.c'],
                 includes = conf['includes'],
-- 
2.16.4