Add option to merge processes of same application

Experimental - Linux only

Closes: htop-dev#301

Action.c

@@ -234,6 +234,11 @@ static Htop_Reaction actionToggleTreeView(State* st) {
    return HTOP_REFRESH | HTOP_SAVE_SETTINGS | HTOP_KEEP_FOLLOWING | HTOP_REDRAW_BAR | HTOP_UPDATE_PANELHDR;
 }
 
+static Htop_Reaction actionToggleMergeApplication(State* st) {
+   st->settings->mergeApplications = !st->settings->mergeApplications;
+   return HTOP_REFRESH | HTOP_SAVE_SETTINGS;
+}
+
 static Htop_Reaction actionIncFilter(State* st) {
    IncSet* inc = ((MainPanel*)st->panel)->inc;
    IncSet_activate(inc, INC_FILTER, st->panel);
@@ -470,6 +475,7 @@ static const struct {
    { .key = "      x: ", .info = "list file locks of process" },
    { .key = "      s: ", .info = "trace syscalls with strace" },
    { .key = "      w: ", .info = "wrap process command in multiple lines" },
+   { .key = "      A: ", .info = "Merge processes of same application" },
    { .key = " F2 C S: ", .info = "setup" },
    { .key = "   F1 h: ", .info = "show this help screen" },
    { .key = "  F10 q: ", .info = "quit" },
@@ -636,6 +642,7 @@ void Action_setBindings(Htop_Action* keys) {
    keys['='] = actionExpandOrCollapse;
    keys['>'] = actionSetSortColumn;
    keys['?'] = actionHelp;
+   keys['A'] = actionToggleMergeApplication;
    keys['C'] = actionSetup;
    keys['F'] = Action_follow;
    keys['H'] = actionToggleUserlandThreads;

DisplayOptionsPanel.c

@@ -98,6 +98,7 @@ DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager*
    Panel_setHeader(super, "Display options");
    Panel_add(super, (Object*) CheckItem_newByRef("Tree view", &(settings->treeView)));
    Panel_add(super, (Object*) CheckItem_newByRef("- Tree view is always sorted by PID (htop 2 behavior)", &(settings->treeViewAlwaysByPID)));
+   Panel_add(super, (Object*) CheckItem_newByRef("Merge processes of same applications", &(settings->mergeApplications)));
    Panel_add(super, (Object*) CheckItem_newByRef("Shadow other users' processes", &(settings->shadowOtherUsers)));
    Panel_add(super, (Object*) CheckItem_newByRef("Hide kernel threads", &(settings->hideKernelThreads)));
    Panel_add(super, (Object*) CheckItem_newByRef("Hide userland process threads", &(settings->hideUserlandThreads)));

Process.c

@@ -287,6 +287,11 @@ void Process_writeField(const Process* this, RichString* str, ProcessField field
          baseattr = CRT_colors[PROCESS_THREAD_BASENAME];
       }
       if (!this->settings->treeView || this->indent == 0) {
+         if (this->merged > 1) {
+            char merged[16];
+            xSnprintf(merged, sizeof(merged), "[%u] ", this->merged);
+            RichString_appendAscii(str, CRT_colors[PROCESS_SHADOW], merged);
+         }
          Process_writeCommand(this, attr, baseattr, str);
          return;
       } else {
@@ -320,6 +325,11 @@ void Process_writeField(const Process* this, RichString* str, ProcessField field
          const char* draw = CRT_treeStr[lastItem ? TREE_STR_BEND : TREE_STR_RTEE];
          xSnprintf(buf, n, "%s%s ", draw, this->showChildren ? CRT_treeStr[TREE_STR_SHUT] : CRT_treeStr[TREE_STR_OPEN] );
          RichString_appendWide(str, CRT_colors[PROCESS_TREE], buffer);
+         if (this->merged > 1) {
+            char merged[16];
+            xSnprintf(merged, sizeof(merged), "[%u] ", this->merged);
+            RichString_appendAscii(str, CRT_colors[PROCESS_SHADOW], merged);
+         }
          Process_writeCommand(this, attr, baseattr, str);
          return;
       }
@@ -488,6 +498,33 @@ int Process_pidCompare(const void* v1, const void* v2) {
    return SPACESHIP_NUMBER(p1->pid, p2->pid);
 }
 
+static bool isTransitiveChildOf(const Process* child, const Process* parent) {
+   assert(child->processList == parent->processList);
+
+   for (const Process* tChild = child; tChild; tChild = ProcessList_findProcess(parent->processList, Process_getParentPid(tChild)))
+      if (Process_isChildOf(tChild, parent->pid))
+         return true;
+
+   return false;
+}
+
+int Process_sameApplication(const Process* v1, const Process* v2) {
+   if (v1->session != v2->session)
+      return 0;
+
+   // we can compare pointers since the field user points to a hashtable entry
+   if (v1->user != v2->user)
+      return 0;
+
+   if (isTransitiveChildOf(v1, v2))
+      return 2;
+
+   if (isTransitiveChildOf(v2, v1))
+      return 1;
+
+   return 0;
+}
+
 int Process_compare(const void* v1, const void* v2) {
    const Process *p1, *p2;
    const Settings *settings = ((const Process*)v1)->settings;
@@ -567,3 +604,33 @@ int Process_compareByKey_Base(const Process* p1, const Process* p2, ProcessField
       return SPACESHIP_NUMBER(p1->pid, p2->pid);
    }
 }
+
+void Process_mergeData(Process* p1, const Process* p2) {
+
+   p1->percent_cpu += p2->percent_cpu;
+   p1->percent_mem += p2->percent_mem;
+   // keep COMM
+   p1->majflt += p2->majflt;
+   p1->minflt += p2->minflt;
+   p1->m_resident += p2->m_resident;
+   p1->m_virt += p2->m_virt;
+   // store min NICE
+   p1->nice = MINIMUM(p1->nice, p2->nice);
+   p1->nlwp += p2->nlwp;
+   // keep PGRP
+   // keep PID
+   // keep PPID
+   p1->priority = MAXIMUM(p1->priority, p2->priority);
+   // keep PROCESSOR
+   // keep SESSION
+   p1->starttime_ctime = MINIMUM(p1->starttime_ctime, p2->starttime_ctime);
+   // keep STATE
+   // keep ST_UID
+   p1->time += p2->time;
+   // keep TGID
+   // keep TPGID
+   // keep TTY_NR
+   // keep USER
+
+   p1->merged += p2->merged;
+}

Process.h

@@ -109,6 +109,8 @@ typedef struct Process_ {
    unsigned int tree_right;
    unsigned int tree_depth;
    unsigned int tree_index;
+
+   unsigned int merged;
 } Process;
 
 typedef struct ProcessFieldData_ {
@@ -122,6 +124,11 @@ typedef struct ProcessFieldData_ {
 // Implemented in platform-specific code:
 void Process_writeField(const Process* this, RichString* str, ProcessField field);
 int Process_compare(const void* v1, const void* v2);
+/* returns 1 on match and if v1 is the master process,
+ *         2 on match and if v2 is the master process,
+ *         0 else */
+int Process_sameApplication(const Process* p1, const Process* p2);
+void Process_mergeData(Process* p1, const Process* p2);
 void Process_delete(Object* cast);
 bool Process_isThread(const Process* this);
 extern const ProcessFieldData Process_fields[LAST_PROCESSFIELD];
@@ -132,12 +139,16 @@ typedef Process*(*Process_New)(const struct Settings_*);
 typedef void (*Process_WriteField)(const Process*, RichString*, ProcessField);
 typedef int (*Process_CompareByKey)(const Process*, const Process*, ProcessField);
 typedef const char* (*Process_GetCommandStr)(const Process*);
+typedef int (*Process_SameApplication)(const Process*, const Process*);
+typedef void (*Process_MergeData)(Process*, const Process*);
 
 typedef struct ProcessClass_ {
    const ObjectClass super;
    const Process_WriteField writeField;
    const Process_CompareByKey compareByKey;
    const Process_GetCommandStr getCommandStr;
+   const Process_SameApplication sameApplication;
+   const Process_MergeData mergeData;
 } ProcessClass;
 
 #define As_Process(this_)                              ((const ProcessClass*)((this_)->super.klass))