Write a log list for uploaded WebRTC logs.

chrome/browser/media/webrtc_log_uploader.cc

Index: chrome/browser/media/webrtc_log_uploader.cc
diff --git a/chrome/browser/media/webrtc_log_uploader.cc b/chrome/browser/media/webrtc_log_uploader.cc
index f88e3821ada4ca34a3d27a3a5bc6fed882169957..9f53cdd3911763b9de5afb291af2d068daa640a6 100644
--- a/chrome/browser/media/webrtc_log_uploader.cc
+++ b/chrome/browser/media/webrtc_log_uploader.cc
@@ -4,9 +4,16 @@
 
 #include "chrome/browser/media/webrtc_log_uploader.h"
 
+#include "base/files/file_path.h"
 #include "base/logging.h"
+#include "base/path_service.h"
 #include "base/shared_memory.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
+#include "base/time.h"
+#include "chrome/browser/media/webrtc_log_upload_list.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/partial_circular_buffer.h"
 #include "content/public/browser/browser_thread.h"
@@ -24,6 +31,7 @@ namespace {
 
 const int kLogCountLimit = 5;
 const uint32 kIntermediateCompressionBufferBytes = 256 * 1024;  // 256 KB
+const int kLogListLimitLines = 50;
 
 const char kUploadURL[] = "https://clients2.google.com/cr/report";
 const char kUploadContentType[] = "multipart/form-data";
@@ -41,6 +49,77 @@ WebRtcLogUploader::~WebRtcLogUploader() {
 
 void WebRtcLogUploader::OnURLFetchComplete(
     const net::URLFetcher* source) {
+  // Append information (time and report ID) about this uploaded log to a log
+  // list file, limited to |kLogListLimitLines| entries. This list is used for
+  // viewing the uploaded logs under chrome://webrtc-logs, see
+  // WebRtcLogUploadList. The list has the format
+  // time,id
+  // time,id
+  // etc.
+  // where each line represents an uploaded log and "time" is Unix time.
+
+  int response_code = source->GetResponseCode();
+  std::string report_id;
+  if (response_code != 200 ||
+      !source->GetResponseAsString(&report_id)) {
+    return;
+  }
+
+  base::FilePath log_dir_path;
+  PathService::Get(chrome::DIR_USER_DATA, &log_dir_path);
+  base::FilePath upload_log_path =
+      log_dir_path.AppendASCII(WebRtcLogUploadList::kWebRtcLogListFilename);
+
+  int flags = base::PLATFORM_FILE_OPEN_ALWAYS |
+              base::PLATFORM_FILE_READ |
+              base::PLATFORM_FILE_WRITE;
+  base::PlatformFileError error = base::PLATFORM_FILE_OK;
+  base::PlatformFile logs_uploaded_file =
+      base::CreatePlatformFile(upload_log_path, flags, NULL, &error);
+  if (error != base::PLATFORM_FILE_OK) {
+    LOG(WARNING) << "Could not open WebRTC log list file.";
+    return;
+  }
+
+  // Read the log list file. Each line is ~35 chars (bytes). Use a buffer size
+  // of 3 times the estimated max size to have a margin.
+  std::string contents(3 * kLogListLimitLines * 35, '\0');
+  size_t read = base::ReadPlatformFileAtCurrentPos(logs_uploaded_file,
+                                                   &contents[0],
+                                                   contents.size());
+  DCHECK_LT(read, contents.size());
+  contents.resize(read);
+
+  // Limit the number of log entries to |kLogListLimitLines| - 1, to make room
+  // for the new entry. Each line including the last ends with a '\n', so hit
+  // n will be before line n-1 (from the back).
+  if (!contents.empty()) {
+    int lf_count = 0;
+    int i = contents.size() - 1;
+    for (; i >= 0 && lf_count < kLogListLimitLines; --i) {
+      if (contents[i] == '\n')
+        ++lf_count;
+    }
+    // + 1 to compensate for the for loop decrease before the conditional check
+    // and + 1 to get the length.
+    contents.erase(0, i + 2);

[tommi (sloooow) - chröme, 2013/06/28 11:00:05]

I think we'll then also need to add a check if i > 0 before we do this.
The reason is that if we don't reach the limit, i will be -1 after the loop, we
increment to 1 and delete the first character of the string.

... thinking about that a bit more though, I think we need to do this slightly
differently assuming that we only want to trim whole lines.

I think you need to add a new variable to keep track of the last eol you found.
Then modify the condition in the loop to be something like:
  if (contents[i] == '\n') {
    ++lf_count;
    eol_pos = i;
  }

After the loop you can then do:

if (lf_count >= kLogListLimitLines)
  contents.erase(0, eol_pos + 1);

[Henrik Grunell, 2013/06/28 14:12:23]

Good point. Added check.

+  }
+
+  // Write the Unix time and report ID to the log list file.
+  base::Time time_now = base::Time::Now();
+  contents += base::DoubleToString(time_now.ToDoubleT()) +
+              "," + report_id + '\n';
+
+  base::SeekPlatformFile(logs_uploaded_file, base::PLATFORM_FILE_FROM_BEGIN, 0);
+  size_t written = base::WritePlatformFileAtCurrentPos(logs_uploaded_file,
+                                                       contents.c_str(),
+                                                       contents.size());
+  DCHECK_EQ(written, contents.size());
+  bool ret = base::TruncatePlatformFile(logs_uploaded_file, written);
+  DPCHECK(ret);
+
+  ret = base::ClosePlatformFile(logs_uploaded_file);
+  DPCHECK(ret);
 }
 
 void WebRtcLogUploader::OnURLFetchUploadProgress(