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/*
* Copyright 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "pc/dtmf_sender.h"
#include <ctype.h>
#include <string.h>
#include "api/task_queue/pending_task_safety_flag.h"
#include "api/task_queue/task_queue_base.h"
#include "api/units/time_delta.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
namespace webrtc {
// RFC4733
// +-------+--------+------+---------+
// | Event | Code | Type | Volume? |
// +-------+--------+------+---------+
// | 0--9 | 0--9 | tone | yes |
// | * | 10 | tone | yes |
// | # | 11 | tone | yes |
// | A--D | 12--15 | tone | yes |
// +-------+--------+------+---------+
// The "," is a special event defined by the WebRTC spec. It means to delay for
// 2 seconds before processing the next tone. We use -1 as its code.
static const int kDtmfCommaDelay = -1;
static const char kDtmfValidTones[] = ",0123456789*#ABCDabcd";
static const char kDtmfTonesTable[] = ",0123456789*#ABCD";
// The duration cannot be more than 6000ms or less than 40ms. The gap between
// tones must be at least 50 ms.
// Source for values: W3C WEBRTC specification.
// https://w3c.github.io/webrtc-pc/#dom-rtcdtmfsender-insertdtmf
static const int kDtmfDefaultDurationMs = 100;
static const int kDtmfMinDurationMs = 40;
static const int kDtmfMaxDurationMs = 6000;
static const int kDtmfDefaultGapMs = 50;
static const int kDtmfMinGapMs = 30;
// Get DTMF code from the DTMF event character.
bool GetDtmfCode(char tone, int* code) {
// Convert a-d to A-D.
char event = toupper(tone);
const char* p = strchr(kDtmfTonesTable, event);
if (!p) {
return false;
}
*code = p - kDtmfTonesTable - 1;
return true;
}
rtc::scoped_refptr<DtmfSender> DtmfSender::Create(
TaskQueueBase* signaling_thread,
DtmfProviderInterface* provider) {
if (!signaling_thread) {
return nullptr;
}
return rtc::make_ref_counted<DtmfSender>(signaling_thread, provider);
}
DtmfSender::DtmfSender(TaskQueueBase* signaling_thread,
DtmfProviderInterface* provider)
: observer_(nullptr),
signaling_thread_(signaling_thread),
provider_(provider),
duration_(kDtmfDefaultDurationMs),
inter_tone_gap_(kDtmfDefaultGapMs),
comma_delay_(kDtmfDefaultCommaDelayMs) {
RTC_DCHECK(signaling_thread_);
RTC_DCHECK(provider_);
}
void DtmfSender::OnDtmfProviderDestroyed() {
RTC_DCHECK_RUN_ON(signaling_thread_);
RTC_DLOG(LS_INFO) << "The Dtmf provider is deleted. Clear the sending queue.";
StopSending();
provider_ = nullptr;
}
DtmfSender::~DtmfSender() {
RTC_DCHECK_RUN_ON(signaling_thread_);
StopSending();
}
void DtmfSender::RegisterObserver(DtmfSenderObserverInterface* observer) {
RTC_DCHECK_RUN_ON(signaling_thread_);
observer_ = observer;
}
void DtmfSender::UnregisterObserver() {
RTC_DCHECK_RUN_ON(signaling_thread_);
observer_ = nullptr;
}
bool DtmfSender::CanInsertDtmf() {
RTC_DCHECK_RUN_ON(signaling_thread_);
if (!provider_) {
return false;
}
return provider_->CanInsertDtmf();
}
bool DtmfSender::InsertDtmf(const std::string& tones,
int duration,
int inter_tone_gap,
int comma_delay) {
RTC_DCHECK_RUN_ON(signaling_thread_);
if (duration > kDtmfMaxDurationMs || duration < kDtmfMinDurationMs ||
inter_tone_gap < kDtmfMinGapMs || comma_delay < kDtmfMinGapMs) {
RTC_LOG(LS_ERROR)
<< "InsertDtmf is called with invalid duration or tones gap. "
"The duration cannot be more than "
<< kDtmfMaxDurationMs << "ms or less than " << kDtmfMinDurationMs
<< "ms. The gap between tones must be at least " << kDtmfMinGapMs
<< "ms.";
return false;
}
if (!CanInsertDtmf()) {
RTC_LOG(LS_ERROR)
<< "InsertDtmf is called on DtmfSender that can't send DTMF.";
return false;
}
tones_ = tones;
duration_ = duration;
inter_tone_gap_ = inter_tone_gap;
comma_delay_ = comma_delay;
// Cancel any remaining tasks for previous tones.
if (safety_flag_) {
safety_flag_->SetNotAlive();
}
safety_flag_ = PendingTaskSafetyFlag::Create();
// Kick off a new DTMF task.
QueueInsertDtmf(1 /*ms*/);
return true;
}
std::string DtmfSender::tones() const {
RTC_DCHECK_RUN_ON(signaling_thread_);
return tones_;
}
int DtmfSender::duration() const {
RTC_DCHECK_RUN_ON(signaling_thread_);
return duration_;
}
int DtmfSender::inter_tone_gap() const {
RTC_DCHECK_RUN_ON(signaling_thread_);
return inter_tone_gap_;
}
int DtmfSender::comma_delay() const {
RTC_DCHECK_RUN_ON(signaling_thread_);
return comma_delay_;
}
void DtmfSender::QueueInsertDtmf(uint32_t delay_ms) {
signaling_thread_->PostDelayedHighPrecisionTask(
SafeTask(safety_flag_,
[this] {
RTC_DCHECK_RUN_ON(signaling_thread_);
DoInsertDtmf();
}),
TimeDelta::Millis(delay_ms));
}
void DtmfSender::DoInsertDtmf() {
// Get the first DTMF tone from the tone buffer. Unrecognized characters will
// be ignored and skipped.
size_t first_tone_pos = tones_.find_first_of(kDtmfValidTones);
int code = 0;
if (first_tone_pos == std::string::npos) {
tones_.clear();
// Fire a “OnToneChange” event with an empty string and stop.
if (observer_) {
observer_->OnToneChange(std::string(), tones_);
observer_->OnToneChange(std::string());
}
return;
} else {
char tone = tones_[first_tone_pos];
if (!GetDtmfCode(tone, &code)) {
// The find_first_of(kDtmfValidTones) should have guarantee `tone` is
// a valid DTMF tone.
RTC_DCHECK_NOTREACHED();
}
}
int tone_gap = inter_tone_gap_;
if (code == kDtmfCommaDelay) {
// Special case defined by WebRTC - By default, the character ',' indicates
// a delay of 2 seconds before processing the next character in the tones
// parameter. The comma delay can be set to a non default value via
// InsertDtmf to comply with legacy WebRTC clients.
tone_gap = comma_delay_;
} else {
if (!provider_) {
RTC_LOG(LS_ERROR) << "The DtmfProvider has been destroyed.";
return;
}
// The provider starts playout of the given tone on the
// associated RTP media stream, using the appropriate codec.
if (!provider_->InsertDtmf(code, duration_)) {
RTC_LOG(LS_ERROR) << "The DtmfProvider can no longer send DTMF.";
return;
}
// Wait for the number of milliseconds specified by `duration_`.
tone_gap += duration_;
}
// Fire a “OnToneChange” event with the tone that's just processed.
if (observer_) {
observer_->OnToneChange(tones_.substr(first_tone_pos, 1),
tones_.substr(first_tone_pos + 1));
observer_->OnToneChange(tones_.substr(first_tone_pos, 1));
}
// Erase the unrecognized characters plus the tone that's just processed.
tones_.erase(0, first_tone_pos + 1);
// Continue with the next tone.
QueueInsertDtmf(tone_gap);
}
void DtmfSender::StopSending() {
if (safety_flag_) {
safety_flag_->SetNotAlive();
}
}
} // namespace webrtc
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