capture stdout and display in dialog window

tools/lammps-gui/CMakeLists.txt

@@ -61,6 +61,7 @@ set(PROJECT_SOURCES
   lammpsgui.cpp
   lammpsgui.h
   lammpsgui.ui
+  stdcapture.cpp
 )
 
 if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)

tools/lammps-gui/lammpsgui.cpp

@@ -13,12 +13,15 @@
 
 #include "lammpsgui.h"
 #include "highlighter.h"
+#include "stdcapture.h"
 #include "ui_lammpsgui.h"
 
 #include <QFileDialog>
 #include <QFileInfo>
 #include <QFont>
 #include <QMessageBox>
+#include <QPlainTextEdit>
+#include <QShortcut>
 #include <QTextStream>
 #include <string>
 
@@ -30,12 +33,14 @@ LammpsGui::LammpsGui(QWidget *parent, const char *filename) :
     ui->setupUi(this);
     this->setCentralWidget(ui->textEdit);
     current_file.clear();
+    capturer = new StdCapture;
 
     QFont text_font;
     text_font.setFamily("Consolas");
     text_font.setFixedPitch(true);
     text_font.setStyleHint(QFont::TypeWriter);
     ui->textEdit->document()->setDefaultFont(text_font);
+    ui->textEdit->setMinimumSize(800, 600);
     highlighter = new Highlighter(ui->textEdit->document());
 
     connect(ui->actionNew, &QAction::triggered, this, &LammpsGui::new_document);
@@ -68,6 +73,7 @@ LammpsGui::~LammpsGui()
 {
     delete ui;
     delete highlighter;
+    delete capturer;
 }
 
 void LammpsGui::new_document()
@@ -187,15 +193,34 @@ void LammpsGui::run_buffer()
     start_lammps();
     if (!lammps_handle) return;
     clear();
+    capturer->BeginCapture();
     std::string buffer = ui->textEdit->toPlainText().toStdString();
     lammps_commands_string(lammps_handle, buffer.c_str());
+    capturer->EndCapture();
+    auto log = capturer->GetCapture();
+    auto box = new QPlainTextEdit();
+    box->document()->setPlainText(log.c_str());
+    box->setReadOnly(true);
+
+    QFont text_font;
+    text_font.setFamily("Consolas");
+    text_font.setFixedPitch(true);
+    text_font.setStyleHint(QFont::TypeWriter);
+    box->document()->setDefaultFont(text_font);
+    box->setLineWrapMode(QPlainTextEdit::NoWrap);
+    box->setMinimumSize(800, 600);
+    QShortcut *shortcut = new QShortcut(QKeySequence(Qt::CTRL + Qt::Key_W), box);
+//    QObject::connect(shortcut, &QShortcut::activated, box, &QPlainTextEdit::close());
+
+    box->show();
 
     if (lammps_has_error(lammps_handle)) {
         constexpr int BUFLEN = 1024;
         char errorbuf[BUFLEN];
         lammps_get_last_error_message(lammps_handle, errorbuf, BUFLEN);
 
-        QMessageBox::warning(this, "LAMMPS-GUI Error", QString("Error running LAMMPS:\n\n") + errorbuf);
+        QMessageBox::warning(this, "LAMMPS-GUI Error",
+                             QString("Error running LAMMPS:\n\n") + errorbuf);
     }
 }
 
@@ -212,7 +237,8 @@ void LammpsGui::about()
     start_lammps();
 
     std::string version = "This is LAMMPS-GUI version 0.1\n";
-    if (lammps_handle) version += "using LAMMPS Version " + std::to_string(lammps_version(lammps_handle));
+    if (lammps_handle)
+        version += "using LAMMPS Version " + std::to_string(lammps_version(lammps_handle));
     QMessageBox::information(this, "About LAMMPS-GUI", version.c_str());
 }
 

tools/lammps-gui/lammpsgui.h

@@ -26,6 +26,7 @@ class LammpsGui;
 QT_END_NAMESPACE
 
 class Highlighter;
+class StdCapture;
 
 class LammpsGui : public QMainWindow {
     Q_OBJECT
@@ -57,6 +58,7 @@ private slots:
 private:
     Ui::LammpsGui *ui;
     Highlighter *highlighter;
+    StdCapture *capturer;
 
     QString current_file;
     QString current_dir;

tools/lammps-gui/stdcapture.cpp

@@ -0,0 +1,119 @@
+/* ----------------------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   https://www.lammps.org/, Sandia National Laboratories
+   LAMMPS development team: developers@lammps.org
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+   ------------------------------------------------------------------------- */
+
+// adapted from: https://stackoverflow.com/questions/5419356/redirect-stdout-stderr-to-a-string
+
+#include "stdcapture.h"
+
+#ifdef _MSC_VER
+#include <io.h>
+#define popen _popen
+#define pclose _pclose
+#define stat _stat
+#define dup _dup
+#define dup2 _dup2
+#define fileno _fileno
+#define close _close
+#define pipe _pipe
+#define read _read
+#define eof _eof
+#else
+#include <unistd.h>
+#endif
+
+#include <chrono>
+#include <cstdio>
+#include <fcntl.h>
+#include <thread>
+
+StdCapture::StdCapture() : m_capturing(false), m_oldStdOut(0)
+{
+    // make stdout unbuffered so that we don't need to flush the stream
+    setvbuf(stdout, NULL, _IONBF, 0);
+
+    m_pipe[READ]  = 0;
+    m_pipe[WRITE] = 0;
+#if _MSC_VER
+    if (pipe(m_pipe, 65536, O_BINARY) == -1) return;
+#else
+    if (pipe(m_pipe) == -1) return;
+#endif
+    m_oldStdOut = dup(fileno(stdout));
+    if (m_oldStdOut == -1) return;
+}
+
+StdCapture::~StdCapture()
+{
+    if (m_capturing) {
+        EndCapture();
+    }
+    if (m_oldStdOut > 0) close(m_oldStdOut);
+    if (m_pipe[READ] > 0) close(m_pipe[READ]);
+    if (m_pipe[WRITE] > 0) close(m_pipe[WRITE]);
+}
+
+void StdCapture::BeginCapture()
+{
+    if (m_capturing) EndCapture();
+    dup2(m_pipe[WRITE], fileno(stdout));
+    m_capturing = true;
+}
+
+bool StdCapture::EndCapture()
+{
+    if (!m_capturing) return false;
+    dup2(m_oldStdOut, fileno(stdout));
+    m_captured.clear();
+
+    constexpr int bufSize = 1025;
+    char buf[bufSize];
+    int bytesRead;
+    bool fd_blocked;
+
+    do {
+        bytesRead  = 0;
+        fd_blocked = false;
+
+#ifdef _MSC_VER
+        if (!eof(m_pipe[READ])) {
+            bytesRead = read(m_pipe[READ], buf, bufSize - 1);
+        }
+#else
+        bytesRead = read(m_pipe[READ], buf, bufSize - 1);
+#endif
+        if (bytesRead > 0) {
+            buf[bytesRead] = 0;
+            m_captured += buf;
+        } else if (bytesRead < 0) {
+            fd_blocked = ((errno == EAGAIN) || (errno == EWOULDBLOCK) || (errno == EINTR));
+
+            if (fd_blocked) std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        }
+    } while (fd_blocked || (bytesRead == (bufSize - 1)));
+    m_capturing = false;
+    return true;
+}
+
+std::string StdCapture::GetCapture() const
+{
+    std::string::size_type idx = m_captured.find_last_not_of("\r\n");
+    if (idx == std::string::npos) {
+        return m_captured;
+    } else {
+        return m_captured.substr(0, idx + 1);
+    }
+}
+
+// Local Variables:
+// c-basic-offset: 4
+// End:

tools/lammps-gui/stdcapture.h

@@ -0,0 +1,40 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   https://www.lammps.org/, Sandia National Laboratories
+   LAMMPS development team: developers@lammps.org
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#ifndef STDCAPTURE_H
+#define STDCAPTURE_H
+
+#include <string>
+
+class StdCapture {
+public:
+    StdCapture();
+    virtual ~StdCapture();
+
+    void BeginCapture();
+    bool EndCapture();
+    std::string GetCapture() const;
+
+private:
+    enum PIPES { READ, WRITE };
+    int m_pipe[2];
+    int m_oldStdOut;
+    bool m_capturing;
+    bool m_init;
+    std::string m_captured;
+};
+
+#endif
+// Local Variables:
+// c-basic-offset: 4
+// End: