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[libvirt] [PATCH v5 1/3] vsh: Add API for printing tables.



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 redhat com>
---
 tools/Makefile.am |   4 +-
 tools/vsh-table.c | 449 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/vsh-table.h |  42 +++++
 3 files changed, 494 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 1452d984a0..f069167acc 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..ca4e9265c5
--- /dev/null
+++ b/tools/vsh-table.c
@@ -0,0 +1,449 @@
+/*
+ * 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 redhat com>
+ *
+ */
+
+#include <config.h>
+#include "vsh-table.h"
+
+#include <string.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <wchar.h>
+#include <wctype.h>
+#include "c-ctype.h"
+
+#include "viralloc.h"
+#include "virbuffer.h"
+#include "virstring.h"
+#include "virsh-util.h"
+
+#define HEX_ENCODE_LENGTH 4 /* represents length of '\xNN' */
+
+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;
+
+    if (!arg) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Table row cannot be empty"));
+        goto error;
+    }
+
+    if (VIR_ALLOC(row) < 0)
+        goto error;
+
+    while (arg) {
+        char *tmp = NULL;
+
+        if (VIR_STRDUP(tmp, arg) < 0)
+            goto error;
+
+        if (VIR_APPEND_ELEMENT(row->cells, row->ncells, tmp) < 0) {
+            VIR_FREE(tmp);
+            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 = NULL;
+    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;
+}
+
+/**
+ * Function pulled from util-linux
+ *
+ * Function's name in util-linux: mbs_safe_encode_to_buffer
+ *
+ * Returns allocated string where all control and non-printable chars are
+ * replaced with \x?? hex sequence, or NULL.
+ */
+static char *
+vshTableSafeEncode(const char *s, size_t *width)
+{
+    const char *p = s;
+    size_t sz = s ? strlen(s) : 0;
+    char *buf;
+    char *ret;
+    mbstate_t st;
+
+    memset(&st, 0, sizeof(st));
+
+    if (VIR_ALLOC_N(buf, (sz * HEX_ENCODE_LENGTH) + 1) < 0)
+        return NULL;
+
+    if (!sz)
+        return NULL;
+
+    ret = buf;
+    *width = 0;
+
+    while (p && *p) {
+        if ((*p == '\\' && *(p + 1) == 'x') ||
+            c_iscntrl(*p)) {
+            snprintf(buf, HEX_ENCODE_LENGTH + 1, "\\x%02x", *p);
+            buf += HEX_ENCODE_LENGTH;
+            *width += HEX_ENCODE_LENGTH;
+            p++;
+        } else {
+            wchar_t wc;
+            size_t len = mbrtowc(&wc, p, MB_CUR_MAX, &st);
+
+            if (len == 0)
+                break;		/* end of string */
+
+            if (len == (size_t) -1 || len == (size_t) -2) {
+                len = 1;
+                /*
+                 * Not valid multibyte sequence -- maybe it's
+                 * printable char according to the current locales.
+                 */
+                if (!c_isprint(*p)) {
+                    snprintf(buf, HEX_ENCODE_LENGTH + 1, "\\x%02x", *p);
+                    buf += HEX_ENCODE_LENGTH;
+                    *width += HEX_ENCODE_LENGTH;
+                } else {
+                    (*width)++;
+                    *buf++ = *p;
+                }
+            } else if (!iswprint(wc)) {
+                size_t i;
+                for (i = 0; i < len; i++) {
+                    snprintf(buf, HEX_ENCODE_LENGTH + 1, "\\x%02x", p[i]);
+                    buf += HEX_ENCODE_LENGTH;
+                    *width += HEX_ENCODE_LENGTH;
+                }
+            } else {
+                memcpy(buf, p, len);
+                buf += len;
+                *width += wcwidth(wc);
+            }
+            p += len;
+        }
+    }
+
+    *buf = '\0';
+    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)
+ *
+ * Return 0 in case of success, -1 otherwise.
+ */
+static int
+vshTableGetColumnsWidths(vshTablePtr table,
+                         size_t *maxwidths,
+                         size_t **widths,
+                         bool header)
+{
+    size_t i;
+    size_t j;
+
+    i = header? 0 : 1;
+    for (; i < table->nrows; i++) {
+        vshTableRowPtr row = table->rows[i];
+
+        for (j = 0; j < row->ncells; j++) {
+            size_t size = 0;
+            /* need to replace nonprintable and control characters,
+             * because width of some of those characters (e.g. \t, \v, \b ...)
+             * cannot be counted properly */
+            char *tmp = vshTableSafeEncode(row->cells[j], &size);
+            if (!tmp)
+                return -1;
+
+            VIR_FREE(row->cells[j]);
+            row->cells[j] = tmp;
+            widths[i][j] = size;
+
+            if (widths[i][j] > maxwidths[j])
+                maxwidths[j] = widths[i][j];
+        }
+    }
+
+    return 0;
+}
+
+/**
+ * vshTableRowPrint:
+ * @row: table to append to
+ * @maxwidths: maximum count of characters for each columns
+ * @widths: count of character for each cell in this row
+ * @buf: buffer to store table (only if @toStdout == true)
+ */
+static void
+vshTableRowPrint(vshTableRowPtr row,
+                 size_t *maxwidths,
+                 size_t *widths,
+                 virBufferPtr buf)
+{
+    size_t i;
+    size_t j;
+
+    for (i = 0; i < row->ncells; i++) {
+        virBufferAsprintf(buf, " %s", row->cells[i]);
+
+        for (j = 0; j < maxwidths[i] - widths[i] + 2; j++)
+            virBufferAddChar(buf, ' ');
+    }
+    virBufferAddChar(buf, '\n');
+}
+
+/**
+ * vshTablePrint:
+ * @table: table to print
+ * @header: whetever to print to header (true) or not (false)
+ * this argument is relevant only if @ctl == NULL
+ *
+ * Get 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
+ */
+static char *
+vshTablePrint(vshTablePtr table, bool header)
+{
+    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 */
+        vshTableRowPrint(table->rows[0], maxwidths, widths[0], &buf);
+
+        /* print dividing line  */
+        for (i = 0; i < table->rows[0]->ncells; i++) {
+            for (j = 0; j < maxwidths[i] + 3; j++)
+                virBufferAddChar(&buf, '-');
+        }
+        virBufferAddChar(&buf, '\n');
+    }
+    /* print content */
+    for (i = 1; i < table->nrows; i++)
+        vshTableRowPrint(table->rows[i], maxwidths, widths[i], &buf);
+
+    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 returned in string to stdout.
+ * If effect on vshControl structure on priting function changes in future
+ * (apart from quiet mode) this code may need update
+ */
+void
+vshTablePrintToStdout(vshTablePtr table, vshControl *ctl)
+{
+    bool header;
+    char *out;
+
+    header = ctl ? !ctl->quiet : true;
+
+    out = vshTablePrintToString(table, header);
+    if (out)
+        vshPrint(ctl, "%s", out);
+
+    VIR_FREE(out);
+}
+
+/**
+ * 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(table, header);
+}
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 redhat com>
+ *
+ */
+
+#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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