tree: start on massive tree refactor

The big thing going on here is that we are going to split up the libraries
a bit better, and remove GObject from the capture library. The libsysprof
library will bring in the capture library statically, so we can export the
symbols we want.

Eventually, we will bump the version to sysprof-3, but not yet.

src/libsysprof/sp-source-util.c

@@ -0,0 +1,203 @@
+/* sp-source-util.c
+ *
+ * Copyright 2019 Christian Hergert <chergert@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <gio/gio.h>
+#include <string.h>
+
+#include "sp-source-util-private.h"
+
+gboolean
+sp_host_file_get_contents (const gchar  *host_path,
+                           gchar       **contents,
+                           gsize        *len,
+                           GError      **error)
+{
+  g_autofree gchar *alt_path = NULL;
+
+  g_return_val_if_fail (host_path != NULL, FALSE);
+
+  if (!g_file_test ("/.flatpak-info", G_FILE_TEST_EXISTS))
+    return g_file_get_contents (host_path, contents, len, error);
+
+  if (contents != NULL)
+    *contents = NULL;
+
+  if (len != NULL)
+    *len = 0;
+
+  alt_path = g_build_filename ("/var/run/host", host_path, NULL);
+
+  if (g_file_test (alt_path, G_FILE_TEST_EXISTS))
+    return g_file_get_contents (alt_path, contents, len, error);
+
+  /*
+   * Fallback to try to get it with "cat" on the host since we
+   * may not have access (like for /proc) from /var/run/host.
+   */
+
+  {
+    g_autoptr(GSubprocessLauncher) launcher = NULL;
+    g_autoptr(GSubprocess) subprocess = NULL;
+    g_autoptr(GBytes) stdout_buf = NULL;
+
+    launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_STDOUT_PIPE |
+                                          G_SUBPROCESS_FLAGS_STDERR_SILENCE);
+
+    subprocess = g_subprocess_launcher_spawn (launcher, error,
+                                              "flatpak-spawn",
+                                              "--clear-env",
+                                              "--host",
+                                              "cat",
+                                              host_path,
+                                              NULL);
+
+    if (subprocess == NULL)
+      return FALSE;
+
+    if (!g_subprocess_communicate (subprocess, NULL, NULL, &stdout_buf, NULL, error))
+      return FALSE;
+
+    if (len != NULL)
+      *len = g_bytes_get_size (stdout_buf);
+
+    if (contents != NULL)
+      {
+        const guint8 *data;
+        gsize n;
+
+        /* g_file_get_contents() gurantees a trailing null byte */
+        data = g_bytes_get_data (stdout_buf, &n);
+        *contents = g_malloc (n + 1);
+        memcpy (*contents, data, n);
+        (*contents)[n] = '\0';
+      }
+  }
+
+  return TRUE;
+}
+
+gchar **
+sp_host_list_directories (const gchar  *directory,
+                          GError      **error)
+{
+  g_autofree gchar *alt_path = NULL;
+
+  g_return_val_if_fail (directory != NULL, NULL);
+
+  if (g_file_test ("/.flatpak-info", G_FILE_TEST_IS_REGULAR))
+    {
+      g_autoptr(GSubprocessLauncher) launcher = NULL;
+      g_autoptr(GSubprocess) subprocess = NULL;
+      g_autofree gchar *stdout_buf = NULL;
+      g_auto(GStrv) lines = NULL;
+      gsize len;
+      guint j = 0;
+
+      alt_path = g_build_filename ("/var/run/host", directory, NULL);
+
+      if (g_file_test (alt_path, G_FILE_TEST_IS_DIR))
+        {
+          directory = alt_path;
+          goto try_native;
+        }
+
+      launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_STDOUT_PIPE |
+                                            G_SUBPROCESS_FLAGS_STDERR_SILENCE);
+      subprocess = g_subprocess_launcher_spawn (launcher, error,
+                                                "flatpak-spawn",
+                                                "--clear-env",
+                                                "--host",
+                                                "ls",
+                                                "-1",
+                                                "-U",
+                                                "--file-type",
+                                                directory,
+                                                NULL);
+      if (subprocess == NULL)
+        return NULL;
+
+      if (!g_subprocess_communicate_utf8 (subprocess, NULL, NULL, &stdout_buf, NULL, error))
+        return NULL;
+
+      lines = g_strsplit (stdout_buf, "\n", 0);
+      len = g_strv_length (lines);
+
+      for (gsize i = 0; i < len; i++)
+        {
+          gsize llen = strlen (lines[i]);
+
+          if (llen == 0 || lines[i][llen-1] != '/')
+            {
+              /* Remove this entry, we'll compress the list later */
+              g_free (lines[i]);
+              lines[i] = NULL;
+            }
+          else
+            {
+              /* trim trailing / */
+              lines[i][llen-1] = 0;
+            }
+        }
+
+      /* Compress the list by removing NULL links */
+      for (gsize i = 0; i < len; i++)
+        {
+          if (lines[i] == NULL)
+            {
+              if (j <= i)
+                j = i + 1;
+
+              for (; j < len; j++)
+                {
+                  if (lines[j] != NULL)
+                    {
+                      lines[i] = g_steal_pointer (&lines[j]);
+                      break;
+                    }
+                }
+            }
+        }
+
+      return g_steal_pointer (&lines);
+    }
+
+try_native:
+
+    {
+      g_autoptr(GDir) dir = g_dir_open (directory, 0, error);
+      g_autoptr(GPtrArray) dirs = g_ptr_array_new_with_free_func (g_free);
+      const gchar *name;
+
+      if (dir == NULL)
+        return NULL;
+
+      while ((name = g_dir_read_name (dir)))
+        {
+          g_autofree gchar *path = g_build_filename (directory, name, NULL);
+
+          if (g_file_test (path, G_FILE_TEST_IS_DIR))
+            g_ptr_array_add (dirs, g_steal_pointer (&path));
+        }
+
+      g_ptr_array_add (dirs, NULL);
+
+      return (gchar **)g_ptr_array_free (g_steal_pointer (&dirs), FALSE);
+    }
+}