[PATCH v8 15/20] trace-cmd library: Read compressed latency data

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

Extended the latency read logic for reading comperssed latency trace
data. Both decompressing approaches are supported: in-memory and
using temporary file.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-input.c | 77 +++++++++++++++++++++++++++++++++----
 1 file changed, 70 insertions(+), 7 deletions(-)

diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index c52aa951..7d8f0fe4 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -177,6 +177,7 @@ struct tracecmd_input {
 	bool			cpu_compressed;
 	int			file_version;
 	unsigned int		cpustats_size;
+	struct cpu_zdata	latz;
 	struct cpu_data 	*cpu_data;
 	long long		ts_offset;
 	struct tsc2nsec		tsc_calc;
@@ -3485,20 +3486,55 @@ static int read_options_type(struct tracecmd_input *handle)
 
 int tracecmd_latency_data_read(struct tracecmd_input *handle, char **buf, size_t *size)
 {
+	struct cpu_zdata *zdata = &handle->latz;
+	void *data;
+	int rsize;
+	int fd = -1;
+	int id;
+
 	if (!handle || !buf || !size)
 		return -1;
 	if (handle->file_state != TRACECMD_FILE_CPU_LATENCY)
 		return -1;
 
+	if (!handle->cpu_compressed) {
+		fd = handle->fd;
+	} else if (!handle->read_zpage) {
+		if (zdata->fd < 0)
+			return -1;
+		fd = zdata->fd;
+	}
+
 	/* Read data from a file */
-	if (!(*buf)) {
-		*size = BUFSIZ;
-		*buf = malloc(*size);
-		if (!(*buf))
+	if (fd >= 0) {
+		if (!(*buf)) {
+			*size = BUFSIZ;
+			*buf = malloc(*size);
+			if (!(*buf))
+				return -1;
+		}
+		return do_read_fd(fd, *buf, *size);
+	}
+
+	/* Uncompress data in memory */
+	if (zdata->last_chunk >= zdata->count)
+		return 0;
+
+	id = zdata->last_chunk;
+	if (!*buf || *size < zdata->chunks[id].size) {
+		data = realloc(*buf, zdata->chunks[id].size);
+		if (!data)
 			return -1;
+		*buf = data;
+		*size = zdata->chunks[id].size;
 	}
 
-	return do_read(handle, *buf, *size);
+	if (tracecmd_uncompress_chunk(handle->compress, &zdata->chunks[id], *buf))
+		return -1;
+
+	rsize = zdata->chunks[id].size;
+	zdata->last_chunk++;
+	return rsize;
 }
 
 static int init_cpu_data(struct tracecmd_input *handle)
@@ -3566,7 +3602,29 @@ static int init_cpu_data(struct tracecmd_input *handle)
 
 int init_latency_data(struct tracecmd_input *handle)
 {
-	/* To do */
+	unsigned long long wsize;
+	int ret;
+
+	if (!handle->cpu_compressed)
+		return 0;
+
+	if (handle->read_zpage) {
+		handle->latz.count = tracecmd_load_chunks_info(handle->compress, &handle->latz.chunks);
+		if (handle->latz.count < 0)
+			return -1;
+	} else {
+		strcpy(handle->latz.file, COMPR_TEMP_FILE);
+		handle->latz.fd = mkstemp(handle->latz.file);
+		if (handle->latz.fd < 0)
+			return -1;
+
+		ret = tracecmd_uncompress_copy_to(handle->compress, handle->latz.fd, NULL, &wsize);
+		if (ret)
+			return -1;
+
+		lseek64(handle->latz.fd, 0, SEEK_SET);
+	}
+
 	return 0;
 }
 
@@ -4078,6 +4136,7 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
 
 	handle->fd = fd;
 	handle->ref = 1;
+	handle->latz.fd = -1;
 	/* By default, use usecs, unless told otherwise */
 	handle->flags |= TRACECMD_FL_IN_USECS;
 
@@ -4372,7 +4431,11 @@ void tracecmd_close(struct tracecmd_input *handle)
 	free(handle->strings);
 	free(handle->version);
 	close(handle->fd);
-
+	free(handle->latz.chunks);
+	if (handle->latz.fd >= 0) {
+		close(handle->latz.fd);
+		unlink(handle->latz.file);
+	}
 	while (handle->sections) {
 		del_sec = handle->sections;
 		handle->sections = handle->sections->next;
-- 
2.34.1