[PATCH v3 02/20] trace-cmd library: Internal helpers for compressing data

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

New library internal helper functions are introduced, to add compression
functionality to the output trace handler.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/include/trace-cmd-local.h |  7 ++++
 lib/trace-cmd/trace-output.c            | 56 +++++++++++++++++++++++--
 2 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
index fb008678..393d05e8 100644
--- a/lib/trace-cmd/include/trace-cmd-local.h
+++ b/lib/trace-cmd/include/trace-cmd-local.h
@@ -40,6 +40,13 @@ void tracecmd_compress_free(void);
 bool check_file_state(unsigned long file_version, int current_state, int new_state);
 bool check_out_state(struct tracecmd_output *handle, int new_state);
 
+int out_uncompress_block(struct tracecmd_output *handle);
+int out_compression_start(struct tracecmd_output *handle, bool compress);
+int out_compression_end(struct tracecmd_output *handle, bool compress);
+void out_compression_reset(struct tracecmd_output *handle, bool compress);
+unsigned long long out_copy_fd_compress(struct tracecmd_output *handle,
+					int fd, unsigned long long max,
+					unsigned long long *write_size);
 unsigned long long
 out_write_section_header(struct tracecmd_output *handle, unsigned short header_id,
 			 char *description, enum tracecmd_section_flags flags, bool option);
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index a3b75c08..54eec93c 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -64,6 +64,8 @@ struct tracecmd_output {
 	unsigned long		file_version;
 	tsize_t			options_start;
 	bool			big_endian;
+	bool			do_compress;
+	struct tracecmd_compression *compress;
 
 	struct list_head	options;
 	struct list_head	buffers;
@@ -88,18 +90,27 @@ struct list_event_system {
 static stsize_t
 do_write_check(struct tracecmd_output *handle, const void *data, tsize_t size)
 {
+	if (handle->do_compress)
+		return tracecmd_compress_write(handle->compress, data, size);
 	if (handle->msg_handle)
 		return tracecmd_msg_data_send(handle->msg_handle, data, size);
-
 	return __do_write_check(handle->fd, data, size);
 }
 
 static inline off64_t do_lseek(struct tracecmd_output *handle, off_t offset, int whence)
 {
+	if (handle->do_compress)
+		return tracecmd_compress_lseek(handle->compress, offset, whence);
 	if (handle->msg_handle)
 		return msg_lseek(handle->msg_handle, offset, whence);
-	else
-		return lseek64(handle->fd, offset, whence);
+	return lseek64(handle->fd, offset, whence);
+}
+
+static inline int do_preed(struct tracecmd_output *handle, void *dst, int len, off_t offset)
+{
+	if (handle->do_compress)
+		return tracecmd_compress_pread(handle->compress, dst, len, offset);
+	return pread(handle->fd, dst, len, offset);
 }
 
 static short convert_endian_2(struct tracecmd_output *handle, short val)
@@ -127,6 +138,43 @@ static unsigned long long convert_endian_8(struct tracecmd_output *handle,
 	return tep_read_number(handle->pevent, &val, 8);
 }
 
+__hidden void out_compression_reset(struct tracecmd_output *handle, bool compress)
+{
+	if (!compress || !handle->compress)
+		return;
+	tracecmd_compress_reset(handle->compress);
+	handle->do_compress = false;
+}
+
+__hidden int out_uncompress_block(struct tracecmd_output *handle)
+{
+	int ret = 0;
+
+	if (!handle->compress)
+		return 0;
+	ret = tracecmd_uncompress_block(handle->compress);
+	if (!ret)
+		handle->do_compress = true;
+	return ret;
+}
+
+__hidden int out_compression_start(struct tracecmd_output *handle, bool compress)
+{
+	if (!compress || !handle->compress)
+		return 0;
+	tracecmd_compress_reset(handle->compress);
+	handle->do_compress = true;
+	return 0;
+}
+
+__hidden int out_compression_end(struct tracecmd_output *handle, bool compress)
+{
+	if (!compress || !handle->compress)
+		return 0;
+	handle->do_compress = false;
+	return tracecmd_compress_block(handle->compress);
+}
+
 /**
  * tracecmd_set_quiet - Set if to print output to the screen
  * @quiet: If non zero, print no output to the screen
@@ -1544,7 +1592,7 @@ static int append_options_v6(struct tracecmd_output *handle)
 	if (offset == (off_t)-1)
 		return -1;
 
-	r = pread(handle->fd, &option, 2, offset);
+	r = do_preed(handle, &option, 2, offset);
 	if (r != 2 || option != TRACECMD_OPTION_DONE)
 		return -1;
 
-- 
2.31.1