gestures: Move metrics finger tracking to std::vector

FingerMetrics currently uses a custom vector with a fixed size to track
currently touching fingers. Replace this customer vector with
std::vector to track an indefinite number of fingers.

BUG=b:322173064
TEST=Deployed to DUT and tested with trackpad that would otherwise
generate "out of space" error.

Change-Id: I362b75847b6753f2fac9d2e076727cabe129f12a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/gestures/+/5320049
Reviewed-by: Henry Barnor <hbarnor@chromium.org>
Commit-Queue: William Mahon <wmahon@google.com>
Tested-by: William Mahon <wmahon@google.com>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Reviewed-by: Sean O'Brien <seobrien@chromium.org>

3 files changed, 19 insertions, 14 deletions

diff --git a/include/finger_metrics.h b/include/finger_metrics.h
index 1773a94..c1f33dd 100644
--- a/include/finger_metrics.h
+++ b/include/finger_metrics.h
@@ -6,10 +6,10 @@
 #define GESTURES_FINGER_METRICS_H_
 
 #include <cmath>
+#include <vector>
 
 #include "include/gestures.h"
 #include "include/prop_registry.h"
-#include "include/vector.h"
 
 namespace gestures {
 
@@ -130,7 +130,7 @@ class Metrics {
 
   // A collection of FingerMetrics describing the current hardware state.
   // The collection is sorted to yield the oldest finger first.
-  vector<FingerMetrics, kMaxFingers>& fingers() { return fingers_; }
+  std::vector<FingerMetrics>& fingers() { return fingers_; }
 
   // Find a FingerMetrics instance by it's tracking id.
   // Returns nullptr if not found.
@@ -156,7 +156,7 @@ class Metrics {
   void SetFingerOriginTimestampForTesting(short tracking_id, stime_t time);
 
  private:
-  vector<FingerMetrics, kMaxFingers> fingers_;
+  std::vector<FingerMetrics> fingers_;
 
   MetricsProperties* properties_;
   std::unique_ptr<MetricsProperties> own_properties_;
diff --git a/include/immediate_interpreter.h b/include/immediate_interpreter.h
index 1be420e..7f2aa52 100644
--- a/include/immediate_interpreter.h
+++ b/include/immediate_interpreter.h
@@ -13,6 +13,7 @@
 #include "include/macros.h"
 #include "include/prop_registry.h"
 #include "include/tracer.h"
+#include "include/vector.h"
 
 #ifndef GESTURES_IMMEDIATE_INTERPRETER_H_
 #define GESTURES_IMMEDIATE_INTERPRETER_H_
diff --git a/src/finger_metrics.cc b/src/finger_metrics.cc
index a79ea10..4215196 100644
--- a/src/finger_metrics.cc
+++ b/src/finger_metrics.cc
@@ -76,14 +76,17 @@ bool Metrics::CloseEnoughToGesture(const Vector2& pos_a,
          < vert_axis_sq * horiz_axis_sq;
 }
 
-Metrics::Metrics(MetricsProperties* properties) : properties_(properties) {}
+Metrics::Metrics(MetricsProperties* properties) : properties_(properties) {
+  fingers_.reserve(kMaxFingers);
+}
 
 const FingerMetrics* Metrics::GetFinger(short tracking_id) const {
-  auto iter = fingers_.find(FingerMetrics(tracking_id));
-  if (iter != fingers_.end())
-    return iter;
-  else
-    return nullptr;
+  for (auto iter = fingers_.cbegin(); iter != fingers_.cend(); ++iter) {
+    if(iter->tracking_id() == tracking_id) {
+      return &(*iter);
+    }
+  }
+  return nullptr;
 }
 
 const FingerMetrics* Metrics::GetFinger(const FingerState& state) const {
@@ -98,8 +101,7 @@ void Metrics::Update(const HardwareState& hwstate) {
   // create metrics for new fingers
   for (int i=0; i<hwstate.finger_cnt; ++i) {
     const FingerState& state = hwstate.fingers[i];
-    auto iter = fingers_.find(FingerMetrics(state.tracking_id));
-    if (iter == fingers_.end()) {
+    if (GetFinger(state.tracking_id) == nullptr) {
       fingers_.push_back(FingerMetrics(state,
                                        hwstate.timestamp));
       ++new_count;
@@ -138,9 +140,11 @@ void Metrics::Clear() {
 
 void Metrics::SetFingerOriginTimestampForTesting(short tracking_id,
                                                  stime_t time) {
-  if (auto iter = fingers_.find(FingerMetrics(tracking_id));
-      iter != fingers_.end()) {
-    fingers_.erase(iter);
+  for (auto iter = fingers_.begin(); iter != fingers_.end(); ++iter) {
+    if(iter->tracking_id() == tracking_id) {
+      fingers_.erase(iter);
+      break;
+    }
   }
   fingers_.push_back(FingerMetrics(tracking_id, time));
 }