[PATCH v2 1/3] vsh: Add API for printing tables.

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It solves problems with alignment of columns. Width of each column
is calculated by its biggest cell. Should solve unicode bug.
In future, it may be implemented in virsh, virt-admin...

This API has 5 public functions:
- vshTableNew - adds new table and defines its header
- vshTableRowAppend - appends new row (for same number of columns as in
header)
- vshTablePrintToStdout
- vshTablePrintToString
- vshTableFree

https://bugzilla.redhat.com/show_bug.cgi?id=1574624
https://bugzilla.redhat.com/show_bug.cgi?id=1584630

Signed-off-by: Simon Kobyda <skobyda@xxxxxxxxxx>
---
 tools/Makefile.am |   4 +-
 tools/vsh-table.c | 413 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/vsh-table.h |  42 +++++
 3 files changed, 458 insertions(+), 1 deletion(-)
 create mode 100644 tools/vsh-table.c
 create mode 100644 tools/vsh-table.h

diff --git a/tools/Makefile.am b/tools/Makefile.am
index 26c887649e..ed23575aa7 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -144,7 +144,9 @@ libvirt_shell_la_LIBADD = \
 		$(READLINE_LIBS) \
 		../gnulib/lib/libgnu.la \
 		$(NULL)
-libvirt_shell_la_SOURCES = vsh.c vsh.h
+libvirt_shell_la_SOURCES = \
+		vsh.c vsh.h \
+		vsh-table.c vsh-table.h
 
 virt_host_validate_SOURCES = \
 		virt-host-validate.c \
diff --git a/tools/vsh-table.c b/tools/vsh-table.c
new file mode 100644
index 0000000000..8842e4e4fd
--- /dev/null
+++ b/tools/vsh-table.c
@@ -0,0 +1,413 @@
+/*
+ * vsh-table.c: table printing helper
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Simon Kobyda <skobyda@xxxxxxxxxx>
+ *
+ */
+
+#include <config.h>
+#include "vsh-table.h"
+
+#include <string.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <wchar.h>
+#include <locale.h>
+
+#include "viralloc.h"
+#include "virbuffer.h"
+#include "virstring.h"
+#include "virsh-util.h"
+
+typedef void (*vshPrintCB)(vshControl *ctl, const char *fmt, ...);
+
+struct _vshTableRow {
+    char **cells;
+    size_t ncells;
+};
+
+struct _vshTable {
+    vshTableRowPtr *rows;
+    size_t nrows;
+};
+
+static void
+vshTableRowFree(vshTableRowPtr row)
+{
+    size_t i;
+
+    if (!row)
+        return;
+
+    for (i = 0; i < row->ncells; i++)
+        VIR_FREE(row->cells[i]);
+
+    VIR_FREE(row->cells);
+    VIR_FREE(row);
+}
+
+void
+vshTableFree(vshTablePtr table)
+{
+    size_t i;
+
+    if (!table)
+        return;
+
+    for (i = 0; i < table->nrows; i++)
+        vshTableRowFree(table->rows[i]);
+    VIR_FREE(table->rows);
+    VIR_FREE(table);
+}
+
+/**
+ * vshTableRowNew:
+ * @arg: the first argument.
+ * @ap: list of variadic arguments
+ *
+ * Create a new row in the table. Each argument passed
+ * represents a cell in the row.
+ * Return: pointer to vshTableRowPtr row or NULL.
+ */
+static vshTableRowPtr
+vshTableRowNew(const char *arg, va_list ap)
+{
+    vshTableRowPtr row = NULL;
+    char *tmp = NULL;
+
+    if (!arg) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                        _("Table row cannot be empty"));
+        goto error;
+    }
+
+    if (VIR_ALLOC(row) < 0)
+        goto error;
+
+    while (arg) {
+        if (VIR_STRDUP(tmp, arg) < 0)
+            goto error;
+
+        if (VIR_APPEND_ELEMENT(row->cells, row->ncells, tmp) < 0)
+            goto error;
+
+        arg = va_arg(ap, const char *);
+    }
+
+    return row;
+
+ error:
+    vshTableRowFree(row);
+    return NULL;
+}
+
+/**
+ * vshTableNew:
+ * @arg: List of column names (NULL terminated)
+ *
+ * Create a new table.
+ *
+ * Returns: pointer to table or NULL.
+ */
+vshTablePtr
+vshTableNew(const char *arg, ...)
+{
+    vshTablePtr table;
+    vshTableRowPtr header = NULL;
+    va_list ap;
+
+    if (VIR_ALLOC(table) < 0)
+        goto error;
+
+    va_start(ap, arg);
+    header = vshTableRowNew(arg, ap);
+    va_end(ap);
+
+    if (!header)
+        goto error;
+
+    if (VIR_APPEND_ELEMENT(table->rows, table->nrows, header) < 0)
+        goto error;
+
+    return table;
+ error:
+    vshTableRowFree(header);
+    vshTableFree(table);
+    return NULL;
+}
+
+/**
+ * vshTableRowAppend:
+ * @table: table to append to
+ * @arg: cells of the row (NULL terminated)
+ *
+ * Append new row into the @table. The number of cells in the row has
+ * to be equal to the number of cells in the table header.
+ *
+ * Returns: 0 if succeeded, -1 if failed.
+ */
+int
+vshTableRowAppend(vshTablePtr table, const char *arg, ...)
+{
+    vshTableRowPtr row = NULL;
+    size_t ncolumns = table->rows[0]->ncells;
+    va_list ap;
+    int ret = -1;
+
+    va_start(ap, arg);
+    row = vshTableRowNew(arg, ap);
+    va_end(ap);
+
+    if (!row)
+        goto cleanup;
+
+    if (ncolumns != row->ncells) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                        _("Incorrect number of cells in a table row"));
+        goto cleanup;
+    }
+
+    if (VIR_APPEND_ELEMENT(table->rows, table->nrows, row) < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    vshTableRowFree(row);
+    return ret;
+}
+
+/**
+ * vshTableGetColumnsWidths:
+ * @table: table
+ * @maxwidths: maximum count of characters for each columns
+ * @widths: count of characters for each cell in the table
+ *
+ * Fill passed @maxwidths and @widths arrays with maximum number
+ * of characters for columns and number of character per each
+ * table cell, respectively.
+ *
+ * Handle unicode strings (user must have multibyte locale)
+ */
+static int
+vshTableGetColumnsWidths(vshTablePtr table,
+                         size_t *maxwidths,
+                         size_t **widths,
+                         bool header)
+{
+    int ret = -1;
+    size_t i = 1;
+    size_t j;
+    size_t len;
+    int tmp;
+    wchar_t *wstr = NULL;
+    size_t wstrlen;
+
+    if (header)
+        i = 0;
+    else
+        i = 1;
+    for (; i < table->nrows; i++) {
+        vshTableRowPtr row = table->rows[i];
+
+        for (j = 0; j < row->ncells; j++) {
+            /* strlen should return maximum possible length needed */
+            wstrlen = strlen(row->cells[j]);
+            VIR_FREE(wstr);
+            if (VIR_ALLOC_N(wstr, wstrlen) < 0)
+                goto cleanup;
+            /* mbstowcs fails if machine is using singlebyte locale
+             * and user tries to convert unicode(multibyte)
+             * */
+            if (mbstowcs(wstr, row->cells[j], wstrlen) ==
+                (size_t) -1) {
+                len = wstrlen;
+            } else {
+                tmp = wcswidth(wstr, wstrlen);
+                if (tmp < 0)
+                    goto cleanup;
+                len = (size_t)((unsigned)tmp);
+            }
+            widths[i][j] = len;
+            if (len > maxwidths[j])
+                maxwidths[j] = len;
+        }
+    }
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(wstr);
+    return ret;
+}
+
+/**
+ * vshTableRowPrint:
+ * @ctl virtshell control structure
+ * @row: table to append to
+ * @maxwidths: maximum count of characters for each columns
+ * @widths: count of character for each cell in this row
+ * @printCB function for priting table
+ * @buf: buffer to store table (only if @toStdout == true)
+ * @toStdout: whetever print table to Stdout or return in buffer
+ */
+static void
+vshTableRowPrint(vshControl *ctl,
+                 vshTableRowPtr row,
+                 size_t *maxwidths,
+                 size_t *widths,
+                 vshPrintCB printCB,
+                 virBufferPtr buf,
+                 bool toStdout)
+{
+    size_t i;
+    size_t j;
+
+    for (i = 0; i < row->ncells; i++) {
+        if (toStdout)
+            printCB(ctl, " %s", row->cells[i]);
+        else
+            virBufferAsprintf(buf, " %s", row->cells[i]);
+
+        for (j = 0; j < maxwidths[i] - widths[i] + 2; j++) {
+            if (toStdout)
+                printCB(ctl, " ");
+            else
+                virBufferAddStr(buf, " ");
+        }
+    }
+    if (toStdout)
+        printCB(ctl, "\n");
+    else
+        virBufferAddStr(buf, "\n");
+}
+
+/**
+ * vshTablePrint:
+ * @ctl virtshell control structure
+ * @table: table to print
+ * @header: whetever to print to header (true) or not (false)
+ * this argument is relevant only if @ctl == NULL
+ * @toStdout: whetever to print to stdout (true) or return in string
+ *
+ * Print table. To get an alignment of columns right, function
+ * fills 2d array @widths with count of characters in each cell and
+ * array @maxwidths maximum count of character in each column.
+ * Function then prints tables header and content.
+ *
+ * Return string containing table, or NULL if table was printed to
+ * stdout
+ */
+static char *
+vshTablePrint(vshControl *ctl, vshTablePtr table, bool header, bool toStdout)
+{
+    size_t i;
+    size_t j;
+    size_t *maxwidths;
+    size_t **widths;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    char *ret = NULL;
+
+    if (VIR_ALLOC_N(maxwidths, table->rows[0]->ncells))
+        goto cleanup;
+
+    if (VIR_ALLOC_N(widths, table->nrows))
+        goto cleanup;
+
+    /* retrieve widths of columns */
+    for (i = 0; i < table->nrows; i++) {
+        if (VIR_ALLOC_N(widths[i], table->rows[0]->ncells))
+            goto cleanup;
+    }
+
+    if (vshTableGetColumnsWidths(table, maxwidths, widths, header) < 0)
+        goto cleanup;
+
+    if (header) {
+        /* print header */
+        VIR_WARNINGS_NO_PRINTF
+        vshTableRowPrint(ctl, table->rows[0], maxwidths, widths[0],
+                         vshPrintExtra, &buf, toStdout);
+        VIR_WARNINGS_RESET
+
+        /* print dividing line  */
+        for (i = 0; i < table->rows[0]->ncells; i++) {
+            for (j = 0; j < maxwidths[i] + 3; j++) {
+                if (toStdout)
+                    vshPrintExtra(ctl, "-");
+                else
+                    virBufferAddStr(&buf, "-");
+            }
+        }
+        if (toStdout)
+            vshPrintExtra(ctl, "\n");
+        else
+            virBufferAddStr(&buf, "\n");
+    }
+    /* print content */
+    for (i = 1; i < table->nrows; i++) {
+        VIR_WARNINGS_NO_PRINTF
+        vshTableRowPrint(ctl, table->rows[i], maxwidths, widths[i],
+                         vshPrint, &buf, toStdout);
+        VIR_WARNINGS_RESET
+    }
+
+    if (!toStdout)
+        ret = virBufferContentAndReset(&buf);
+
+ cleanup:
+    VIR_FREE(maxwidths);
+    for (i = 0; i < table->nrows; i++)
+        VIR_FREE(widths[i]);
+    VIR_FREE(widths);
+    return ret;
+}
+
+
+/**
+ * vshTablePrintToStdout:
+ * @table: table to print
+ * @ctl virtshell control structure
+ *
+ * Print table to stdout.
+ *
+ */
+void
+vshTablePrintToStdout(vshTablePtr table, vshControl *ctl)
+{
+    bool header;
+    if (ctl)
+        header = !ctl->quiet;
+    else
+        header = true;
+    vshTablePrint(ctl, table, header, true);
+}
+
+/**
+ * vshTablePrintToString:
+ * @table: table to print
+ * @header: whetever to print to header (true) or not (false)
+ *
+ * Return string containing table, or NULL if table was printed to
+ * stdout. User will have to free returned string.
+ */
+char *
+vshTablePrintToString(vshTablePtr table, bool header)
+{
+    return vshTablePrint(NULL, table, header, false);
+}
diff --git a/tools/vsh-table.h b/tools/vsh-table.h
new file mode 100644
index 0000000000..e4e9582b9f
--- /dev/null
+++ b/tools/vsh-table.h
@@ -0,0 +1,42 @@
+/*
+ * vsh-table.h: table printing helper
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Simon Kobyda <skobyda@xxxxxxxxxx>
+ *
+ */
+
+#ifndef VSH_TABLE_H
+# define VSH_TABLE_H
+
+# include "vsh.h"
+
+/* forward declarations */
+typedef struct _vshTable vshTable;
+typedef struct _vshTableRow vshTableRow;
+typedef vshTable *vshTablePtr;
+typedef vshTableRow *vshTableRowPtr;
+
+void vshTableFree(vshTablePtr table);
+vshTablePtr vshTableNew(const char *format, ...);
+int vshTableRowAppend(vshTablePtr table, const char *arg, ...);
+void vshTablePrintToStdout(vshTablePtr table, vshControl *ctl);
+char *vshTablePrintToString(vshTablePtr table, bool header);
+
+#endif /* VSH_TABLE_H */
-- 
2.17.1

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