logd: don't store the map key in its value

The keys are already available when iterating through the maps, so
this only serves to waste memory.

Test: unit tests
Change-Id: Iaf4e389eb0f0990e7113cd78be1773e767a356d4
diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index 04fd59d..625cbde 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -308,8 +308,9 @@
 void LogStatistics::WorstTwoWithThreshold(const LogHashtable<TKey, TEntry>& table, size_t threshold,
                                           int* worst, size_t* worst_sizes,
                                           size_t* second_worst_sizes) const {
+    std::array<const TKey*, 2> max_keys;
     std::array<const TEntry*, 2> max_entries;
-    table.MaxEntries(AID_ROOT, 0, &max_entries);
+    table.MaxEntries(AID_ROOT, 0, max_keys, max_entries);
     if (max_entries[0] == nullptr || max_entries[1] == nullptr) {
         return;
     }
@@ -317,7 +318,7 @@
     // b/24782000: Allow time horizon to extend roughly tenfold, assume average entry length is
     // 100 characters.
     if (*worst_sizes > threshold && *worst_sizes > (10 * max_entries[0]->dropped_count())) {
-        *worst = max_entries[0]->key();
+        *worst = *max_keys[0];
         *second_worst_sizes = max_entries[1]->getSizes();
         if (*second_worst_sizes < threshold) {
             *second_worst_sizes = threshold;
@@ -340,13 +341,14 @@
 void LogStatistics::WorstTwoSystemPids(log_id id, size_t worst_uid_sizes, int* worst,
                                        size_t* second_worst_sizes) const {
     auto lock = std::lock_guard{lock_};
+    std::array<const pid_t*, 2> max_keys;
     std::array<const PidEntry*, 2> max_entries;
-    pidSystemTable[id].MaxEntries(AID_SYSTEM, 0, &max_entries);
+    pidSystemTable[id].MaxEntries(AID_SYSTEM, 0, max_keys, max_entries);
     if (max_entries[0] == nullptr || max_entries[1] == nullptr) {
         return;
     }
 
-    *worst = max_entries[0]->key();
+    *worst = *max_keys[0];
     *second_worst_sizes = worst_uid_sizes - max_entries[0]->getSizes() + max_entries[1]->getSizes();
 }
 
@@ -412,11 +414,12 @@
     }
 }
 
-std::string UidEntry::format(const LogStatistics& stat, log_id_t id) const REQUIRES(stat.lock_) {
-    std::string name = android::base::StringPrintf("%u", uid_);
+std::string UidEntry::format(const LogStatistics& stat, log_id_t id, uid_t uid) const
+        REQUIRES(stat.lock_) {
+    std::string name = android::base::StringPrintf("%u", uid);
     std::string size = android::base::StringPrintf("%zu", getSizes());
 
-    stat.FormatTmp(nullptr, uid_, name, size, 6);
+    stat.FormatTmp(nullptr, uid, name, size, 6);
 
     std::string pruned = "";
     if (worstUidEnabledForLogid(id)) {
@@ -474,19 +477,20 @@
 
     std::string output = formatLine(name, size, pruned);
 
-    if (uid_ != AID_SYSTEM) {
+    if (uid != AID_SYSTEM) {
         return output;
     }
 
     static const size_t maximum_sorted_entries = 32;
-    std::array<const PidEntry*, maximum_sorted_entries> sorted;
-    stat.pidSystemTable[id].MaxEntries(uid_, 0, &sorted);
+    std::array<const pid_t*, maximum_sorted_entries> sorted_pids;
+    std::array<const PidEntry*, maximum_sorted_entries> sorted_entries;
+    stat.pidSystemTable[id].MaxEntries(uid, 0, sorted_pids, sorted_entries);
 
     std::string byPid;
     size_t index;
     bool hasDropped = false;
     for (index = 0; index < maximum_sorted_entries; ++index) {
-        const PidEntry* entry = sorted[index];
+        const PidEntry* entry = sorted_entries[index];
         if (!entry) {
             break;
         }
@@ -496,7 +500,7 @@
         if (entry->dropped_count()) {
             hasDropped = true;
         }
-        byPid += entry->format(stat, id);
+        byPid += entry->format(stat, id, *sorted_pids[index]);
     }
     if (index > 1) {  // print this only if interesting
         std::string ditto("\" ");
@@ -515,9 +519,9 @@
                       std::string("BYTES"), std::string("NUM"));
 }
 
-std::string PidEntry::format(const LogStatistics& stat, log_id_t /* id */) const
+std::string PidEntry::format(const LogStatistics& stat, log_id_t, pid_t pid) const
         REQUIRES(stat.lock_) {
-    std::string name = android::base::StringPrintf("%5u/%u", pid_, uid_);
+    std::string name = android::base::StringPrintf("%5u/%u", pid, uid_);
     std::string size = android::base::StringPrintf("%zu", getSizes());
 
     stat.FormatTmp(name_, uid_, name, size, 12);
@@ -538,9 +542,9 @@
                       std::string("NUM"));
 }
 
-std::string TidEntry::format(const LogStatistics& stat, log_id_t /* id */) const
+std::string TidEntry::format(const LogStatistics& stat, log_id_t, pid_t tid) const
         REQUIRES(stat.lock_) {
-    std::string name = android::base::StringPrintf("%5u/%u", tid(), uid_);
+    std::string name = android::base::StringPrintf("%5u/%u", tid, uid_);
     std::string size = android::base::StringPrintf("%zu", getSizes());
 
     stat.FormatTmp(name_, uid_, name, size, 12);
@@ -562,8 +566,7 @@
                       std::string("BYTES"), std::string(isprune ? "NUM" : ""));
 }
 
-std::string TagEntry::format(const LogStatistics& /* stat */,
-                             log_id_t /* id */) const {
+std::string TagEntry::format(const LogStatistics&, log_id_t, uint32_t) const {
     std::string name;
     if (uid_ == (uid_t)-1) {
         name = android::base::StringPrintf("%7u", key());
@@ -594,8 +597,7 @@
                       std::string("BYTES"), std::string(""));
 }
 
-std::string TagNameEntry::format(const LogStatistics& /* stat */,
-                                 log_id_t /* id */) const {
+std::string TagNameEntry::format(const LogStatistics&, log_id_t, const TagNameKey& key_name) const {
     std::string name;
     std::string pidstr;
     if (pid_ != (pid_t)-1) {
@@ -616,7 +618,7 @@
 
     std::string size = android::base::StringPrintf("%zu", getSizes());
 
-    const char* nameTmp = this->name();
+    const char* nameTmp = key_name.data();
     if (nameTmp) {
         size_t lenSpace = std::max(16 - name.length(), (size_t)1);
         size_t len = EntryBase::TOTAL_LEN - EntryBase::PRUNED_LEN - size.length() - name.length() -
@@ -684,15 +686,16 @@
         REQUIRES(lock_) {
     static const size_t maximum_sorted_entries = 32;
     std::string output;
-    std::array<const TEntry*, maximum_sorted_entries> sorted;
-    table.MaxEntries(uid, pid, &sorted);
+    std::array<const TKey*, maximum_sorted_entries> sorted_keys;
+    std::array<const TEntry*, maximum_sorted_entries> sorted_entries;
+    table.MaxEntries(uid, pid, sorted_keys, sorted_entries);
     bool header_printed = false;
     for (size_t index = 0; index < maximum_sorted_entries; ++index) {
-        const TEntry* entry = sorted[index];
+        const TEntry* entry = sorted_entries[index];
         if (!entry) {
             break;
         }
-        if (entry->getSizes() <= (sorted[0]->getSizes() / 100)) {
+        if (entry->getSizes() <= (sorted_entries[0]->getSizes() / 100)) {
             break;
         }
         if (!header_printed) {
@@ -700,7 +703,7 @@
             output += entry->formatHeader(name, id);
             header_printed = true;
         }
-        output += entry->format(*this, id);
+        output += entry->format(*this, id, *sorted_keys[index]);
     }
     return output;
 }
diff --git a/logd/LogStatistics.h b/logd/LogStatistics.h
index 33a4d63..9f085dc 100644
--- a/logd/LogStatistics.h
+++ b/logd/LogStatistics.h
@@ -44,6 +44,8 @@
     for (log_id_t i = LOG_ID_MIN; (i) < LOG_ID_MAX; (i) = (log_id_t)((i) + 1))
 
 class LogStatistics;
+class UidEntry;
+class PidEntry;
 
 struct LogStatisticsElement {
     uid_t uid;
@@ -95,31 +97,43 @@
     // Returns a sorted array of up to len highest entries sorted by size.  If fewer than len
     // entries are found, their positions are set to nullptr.
     template <size_t len>
-    void MaxEntries(uid_t uid, pid_t pid, std::array<const TEntry*, len>* out) const {
-        auto& retval = *out;
-        retval.fill(nullptr);
-        for (const_iterator it = map.begin(); it != map.end(); ++it) {
-            const TEntry& entry = it->second;
-
-            if (uid != AID_ROOT && uid != entry.uid()) {
+    void MaxEntries(uid_t uid, pid_t pid, std::array<const TKey*, len>& out_keys,
+                    std::array<const TEntry*, len>& out_entries) const {
+        out_keys.fill(nullptr);
+        out_entries.fill(nullptr);
+        for (const auto& [key, entry] : map) {
+            uid_t entry_uid = 0;
+            if constexpr (std::is_same_v<TEntry, UidEntry>) {
+                entry_uid = key;
+            } else {
+                entry_uid = entry.uid();
+            }
+            if (uid != AID_ROOT && uid != entry_uid) {
                 continue;
             }
-            if (pid && entry.pid() && pid != entry.pid()) {
+            pid_t entry_pid = 0;
+            if constexpr (std::is_same_v<TEntry, PidEntry>) {
+                entry_pid = key;
+            } else {
+                entry_pid = entry.pid();
+            }
+            if (pid && entry_pid && pid != entry_pid) {
                 continue;
             }
 
             size_t sizes = entry.getSizes();
             ssize_t index = len - 1;
-            while ((!retval[index] || (sizes > retval[index]->getSizes())) &&
-                   (--index >= 0))
+            while ((!out_entries[index] || sizes > out_entries[index]->getSizes()) && --index >= 0)
                 ;
             if (++index < (ssize_t)len) {
                 size_t num = len - index - 1;
                 if (num) {
-                    memmove(&retval[index + 1], &retval[index],
-                            num * sizeof(retval[0]));
+                    memmove(&out_keys[index + 1], &out_keys[index], num * sizeof(out_keys[0]));
+                    memmove(&out_entries[index + 1], &out_entries[index],
+                            num * sizeof(out_entries[0]));
                 }
-                retval[index] = &entry;
+                out_keys[index] = &key;
+                out_entries[index] = &entry;
             }
         }
     }
@@ -229,10 +243,8 @@
 class UidEntry : public EntryBaseDropped {
   public:
     explicit UidEntry(const LogStatisticsElement& element)
-        : EntryBaseDropped(element), uid_(element.uid), pid_(element.pid) {}
+        : EntryBaseDropped(element), pid_(element.pid) {}
 
-    uid_t key() const { return uid_; }
-    uid_t uid() const { return key(); }
     pid_t pid() const { return pid_; }
 
     void Add(const LogStatisticsElement& element) {
@@ -243,10 +255,9 @@
     }
 
     std::string formatHeader(const std::string& name, log_id_t id) const;
-    std::string format(const LogStatistics& stat, log_id_t id) const;
+    std::string format(const LogStatistics& stat, log_id_t id, uid_t uid) const;
 
   private:
-    const uid_t uid_;
     pid_t pid_;
 };
 
@@ -258,23 +269,16 @@
   public:
     explicit PidEntry(pid_t pid)
         : EntryBaseDropped(),
-          pid_(pid),
           uid_(android::pidToUid(pid)),
           name_(android::pidToName(pid)) {}
     explicit PidEntry(const LogStatisticsElement& element)
-        : EntryBaseDropped(element),
-          pid_(element.pid),
-          uid_(element.uid),
-          name_(android::pidToName(pid_)) {}
+        : EntryBaseDropped(element), uid_(element.uid), name_(android::pidToName(element.pid)) {}
     PidEntry(const PidEntry& element)
         : EntryBaseDropped(element),
-          pid_(element.pid_),
           uid_(element.uid_),
           name_(element.name_ ? strdup(element.name_) : nullptr) {}
     ~PidEntry() { free(name_); }
 
-    pid_t key() const { return pid_; }
-    pid_t pid() const { return key(); }
     uid_t uid() const { return uid_; }
     const char* name() const { return name_; }
 
@@ -301,10 +305,9 @@
     }
 
     std::string formatHeader(const std::string& name, log_id_t id) const;
-    std::string format(const LogStatistics& stat, log_id_t id) const;
+    std::string format(const LogStatistics& stat, log_id_t id, pid_t pid) const;
 
   private:
-    const pid_t pid_;
     uid_t uid_;
     char* name_;
 };
@@ -313,26 +316,21 @@
   public:
     TidEntry(pid_t tid, pid_t pid)
         : EntryBaseDropped(),
-          tid_(tid),
           pid_(pid),
           uid_(android::pidToUid(tid)),
           name_(android::tidToName(tid)) {}
     explicit TidEntry(const LogStatisticsElement& element)
         : EntryBaseDropped(element),
-          tid_(element.tid),
           pid_(element.pid),
           uid_(element.uid),
-          name_(android::tidToName(tid_)) {}
+          name_(android::tidToName(element.tid)) {}
     TidEntry(const TidEntry& element)
         : EntryBaseDropped(element),
-          tid_(element.tid_),
           pid_(element.pid_),
           uid_(element.uid_),
           name_(element.name_ ? strdup(element.name_) : nullptr) {}
     ~TidEntry() { free(name_); }
 
-    pid_t key() const { return tid_; }
-    pid_t tid() const { return key(); }
     pid_t pid() const { return pid_; }
     uid_t uid() const { return uid_; }
     const char* name() const { return name_; }
@@ -362,10 +360,9 @@
     }
 
     std::string formatHeader(const std::string& name, log_id_t id) const;
-    std::string format(const LogStatistics& stat, log_id_t id) const;
+    std::string format(const LogStatistics& stat, log_id_t id, pid_t pid) const;
 
   private:
-    const pid_t tid_;
     pid_t pid_;
     uid_t uid_;
     char* name_;
@@ -392,7 +389,7 @@
     }
 
     std::string formatHeader(const std::string& name, log_id_t id) const;
-    std::string format(const LogStatistics& stat, log_id_t id) const;
+    std::string format(const LogStatistics& stat, log_id_t id, uint32_t) const;
 
   private:
     const uint32_t tag_;
@@ -490,18 +487,11 @@
 class TagNameEntry : public EntryBase {
   public:
     explicit TagNameEntry(const LogStatisticsElement& element)
-        : EntryBase(element),
-          tid_(element.tid),
-          pid_(element.pid),
-          uid_(element.uid),
-          name_(element) {}
+        : EntryBase(element), tid_(element.tid), pid_(element.pid), uid_(element.uid) {}
 
-    const TagNameKey& key() const { return name_; }
     pid_t tid() const { return tid_; }
     pid_t pid() const { return pid_; }
     uid_t uid() const { return uid_; }
-    const char* name() const { return name_.data(); }
-    size_t getNameAllocLength() const { return name_.getAllocLength(); }
 
     void Add(const LogStatisticsElement& element) {
         if (uid_ != element.uid) {
@@ -517,13 +507,12 @@
     }
 
     std::string formatHeader(const std::string& name, log_id_t id) const;
-    std::string format(const LogStatistics& stat, log_id_t id) const;
+    std::string format(const LogStatistics& stat, log_id_t id, const TagNameKey& key_name) const;
 
   private:
     pid_t tid_;
     pid_t pid_;
     uid_t uid_;
-    TagNameKey name_;
 };
 
 // Log Statistics
@@ -584,7 +573,7 @@
             const char* name = it.second.name();
             if (name) size += strlen(name) + 1;
         }
-        for (auto it : tagNameTable) size += it.second.getNameAllocLength();
+        for (auto it : tagNameTable) size += it.first.getAllocLength();
         log_id_for_each(id) {
             size += uidTable[id].sizeOf();
             size += uidTable[id].size() * sizeof(uidTable_t::iterator);