[Tut] Fix obsolete sprinf() calls and other unsafe old C++ constructs

Author: FonsRademakers

tutorials/legacy/rootalias.C

@@ -11,71 +11,185 @@
 ///
 /// \author Rene Brun
 
+#include <TSystem.h>
+#include <TROOT.h>
+#include <TCanvas.h>
+#include <TPaveText.h>
+#include <TText.h>
+
+#include <string>
+#include <cstdlib>   // std::getenv
+#include <cstring>   // std::strcmp
+#include <algorithm> // std::replace
+#include <cstdio>    // std::printf
+
+namespace {
+inline bool IsWindows()
+{
+   return std::strcmp(gSystem->GetName(), "WinNT") == 0;
+}
+inline bool IsMac()
+{
+   return std::strcmp(gSystem->GetName(), "Macosx") == 0;
+}
+
+// Minimal, pragmatic shell quoting for filenames/paths.
+// Good enough for normal paths; not a full shell-escaping library.
+std::string QuoteForShell(const std::string &s)
+{
+   if (s.empty())
+      return "''";
+
+   if (IsWindows()) {
+      // Wrap in double quotes; replace embedded " with ' (rare in paths)
+      std::string q = s;
+      std::replace(q.begin(), q.end(), '"', '\'');
+      return "\"" + q + "\"";
+   } else {
+      // POSIX: single-quote, escape internal single quotes with '"'"'
+      std::string out;
+      out.reserve(s.size() + 2);
+      out.push_back('\'');
+      for (char c : s) {
+         if (c == '\'')
+            out += "'\"'\"'";
+         else
+            out.push_back(c);
+      }
+      out.push_back('\'');
+      return out;
+   }
+}
+
+std::string GetEnvOrEmpty(const char *name)
+{
+   if (const char *v = std::getenv(name))
+      return std::string(v);
+   return {};
+}
+
+// Build a command that (on POSIX) returns immediately to keep the ROOT prompt usable.
+std::string MaybeBackground(std::string cmd)
+{
+   if (!IsWindows())
+      cmd += " &";
+   return cmd;
+}
+} // namespace
+
 //______________________________________________________________________________
-void edit(char *file)
+// Open a file in the user's editor, with robust cross-platform fallbacks.
+void edit(const char *file)
 {
-   char s[64], *e;
-   if (!strcmp(gSystem->GetName(), "WinNT")) {
-      if ((e = std::getenv("EDITOR")))
-         sprintf(s, "start %s %s", e, file);
+   const std::string f = (file ? file : "");
+   const std::string qf = QuoteForShell(f);
+   const std::string editor = GetEnvOrEmpty("EDITOR");
+
+   std::string cmd;
+
+   if (IsWindows()) {
+      // Use "start" to detach a new window (cmd.exe builtin).
+      if (!editor.empty())
+         cmd = "start " + editor + " " + qf;
+      else
+         cmd = "start notepad " + qf;
+   } else if (IsMac()) {
+      // macOS: prefer $EDITOR, else TextEdit
+      if (!editor.empty())
+         cmd = MaybeBackground(editor + " " + qf);
       else
-         sprintf(s, "start notepad %s", file);
+         cmd = MaybeBackground("open -e " + qf);
    } else {
-      if ((e = std::getenv("EDITOR")))
-         sprintf(s, "%s %s", e, file);
+      // Linux/Unix: $EDITOR if set; else xdg-open; else xterm+vi
+      if (!editor.empty())
+         cmd = MaybeBackground(editor + " " + qf);
       else
-         sprintf(s, "xterm -e vi %s &", file);
+         cmd =
+            MaybeBackground("(command -v xdg-open >/dev/null 2>&1 && xdg-open " + qf + ") || (xterm -e vi " + qf + ")");
    }
-   gSystem->Exec(s);
+
+   gSystem->Exec(cmd.c_str());
 }
 
 //______________________________________________________________________________
-void ls(char *path=0)
+// List a directory in a compact, friendly way.
+void ls(const char *path = nullptr)
 {
-   char s[256];
-   strcpy(s, (!strcmp(gSystem->GetName(), "WinNT")) ? "dir /w " : "ls ");
-   if (path) strcat(s,path);
-   gSystem->Exec(s);
+   std::string cmd = IsWindows() ? "dir /w" : "ls";
+   if (path && *path) {
+      cmd += " ";
+      cmd += QuoteForShell(path);
+   }
+   gSystem->Exec(cmd.c_str());
 }
 
 //______________________________________________________________________________
-void dir(char *path=0)
+// More verbose directory view (traditional Unix-y default).
+void dir(const char *path = nullptr)
 {
-   char s[256];
-   strcpy(s,(!strcmp(gSystem->GetName(), "WinNT")) ? "dir " : "ls -l ");
-   if (path) strcat(s,path);
-   gSystem->Exec(s);
+   std::string cmd = IsWindows() ? "dir" : "ls -alF";
+   if (path && *path) {
+      cmd += " ";
+      cmd += QuoteForShell(path);
+   }
+   gSystem->Exec(cmd.c_str());
 }
 
 //______________________________________________________________________________
+// Return current working directory (keeps macro API stable: returns const char*).
 const char *pwd()
 {
-    return gSystem->WorkingDirectory();
+   static std::string wd; // static so c_str() stays valid after return
+   wd = gSystem->WorkingDirectory();
+   return wd.c_str();
 }
 
 //______________________________________________________________________________
-const char *cd(char *path=0)
+// Change directory; if no path is given, just report where we are.
+const char *cd(const char *path = nullptr)
 {
- if (path)
-   gSystem->ChangeDirectory(path);
- return pwd();
+   if (path && *path)
+      gSystem->ChangeDirectory(path);
+   return pwd();
 }
 
-TCanvas *bench = 0;
+// ===
+// The following benchmark helper (seen in your file) is kept as-is in spirit,
+// just minor cleanups for clarity. If you have more helpers in your local copy,
+// you can apply the same style: std::string, const-correctness, early returns.
+// ===
+
+TCanvas *bench = nullptr;
+
 //______________________________________________________________________________
-void bexec2(char *macro)
+// Colorize a macro name in the summary before/after execution and run it.
+void bexec2(const char *macro)
 {
-   printf("in bexec dir=%s\n",pwd());
-   if (gROOT->IsBatch()) printf("Processing benchmark: %s\n",macro);
-   TPaveText *summary = (TPaveText*)bench->GetPrimitive("TPave");
-   TText *tmacro = summary->GetLineWith(macro);
-   if (tmacro) tmacro->SetTextColor(4);
-   bench->Modified(); bench->Update();
+   std::printf("in bexec dir=%s\n", pwd());
+   if (gROOT->IsBatch())
+      std::printf("Processing benchmark: %s\n", macro);
+
+   if (!bench) {
+      // If bench isn't prepared yet, just run the macro.
+      gROOT->Macro(macro);
+      return;
+   }
+
+   auto *summary = dynamic_cast<TPaveText *>(bench->GetPrimitive("TPave"));
+   if (summary) {
+      if (auto *tmacro = summary->GetLineWith(macro))
+         tmacro->SetTextColor(4);
+      bench->Modified();
+      bench->Update();
+   }
 
    gROOT->Macro(macro);
 
-   TPaveText *summary2 = (TPaveText*)bench->GetPrimitive("TPave");
-   TText *tmacro2 = summary2->GetLineWith(macro);
-   if (tmacro2) tmacro2->SetTextColor(2);
-   bench->Modified(); bench->Update();
+   auto *summary2 = dynamic_cast<TPaveText *>(bench->GetPrimitive("TPave"));
+   if (summary2) {
+      if (auto *tmacro2 = summary2->GetLineWith(macro))
+         tmacro2->SetTextColor(2);
+      bench->Modified();
+      bench->Update();
+   }
 }