dot: applet to generate the dot attributed graph language files

This applet can be used to generate data for graphviz tools.
Useful to visualize package dependencies, and possible errors
in the repository.

Usage examples:
  apk dot gnome-desktop | tred | dot -Tpng gnome-desktop.png
    -- to generate simplified dependency chart of gnome-desktop
  apk dot --errors | dot -Tpng index-errors.png
    -- to generate chart visualizing dependency errors in index

src/Makefile

@@ -20,7 +20,7 @@ endif
 progs-y			+= apk
 apk-objs		:= apk.o add.o del.o fix.o update.o info.o \
 			   search.o upgrade.o cache.o ver.o index.o fetch.o \
-			   audit.o verify.o
+			   audit.o verify.o dot.o
 
 libapk.so-objs		:= common.o state.o database.o package.o archive.o \
 			   version.o io.o url.o gunzip.o blob.o hash.o print.o

src/apk_database.h

@@ -84,6 +84,7 @@ struct apk_db_dir_instance {
 #define APK_NAME_TOPLEVEL		0x0001
 #define APK_NAME_REINSTALL		0x0002
 #define APK_NAME_TOPLEVEL_OVERRIDE	0x0004
+#define APK_NAME_VISITED		0x8000
 
 struct apk_name {
 	apk_hash_node hash_node;

src/dot.c

+/* dot.c - Alpine Package Keeper (APK)
+ *
+ * Copyright (C) 2011 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation. See http://www.gnu.org/ for details.
+ */
+
+#include <stdio.h>
+#include <fnmatch.h>
+
+#include "apk_applet.h"
+#include "apk_database.h"
+#include "apk_print.h"
+
+#define S_EVALUATED	-1
+#define S_EVALUATING	-2
+
+struct dot_ctx {
+	int errors_only;
+	int not_empty;
+};
+
+static int dot_parse(void *pctx, struct apk_db_options *dbopts,
+		     int optch, int optindex, const char *optarg)
+{
+	struct dot_ctx *ctx = (struct dot_ctx *) pctx;
+
+	switch (optch) {
+	case 0x10000:
+		ctx->errors_only = 1;
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static void start_graph(struct dot_ctx *ctx)
+{
+	if (ctx->not_empty)
+		return;
+	ctx->not_empty = 1;
+
+	printf( "digraph \"apkindex\" {\n"
+		"  rankdir=LR;\n"
+		"  node [shape=box];\n");
+}
+
+static int dump_pkg(struct dot_ctx *ctx, struct apk_package *pkg)
+{
+	int i, j, r, ret = 0;
+
+	/* Succesfully vandalize the apk_package by reusing
+	 * size field for our evil purposes ;) */
+	if (pkg->size == S_EVALUATED)
+		return 0;
+	if (((ssize_t)pkg->size) <= S_EVALUATING) {
+		pkg->size--;
+		return 1;
+	}
+
+	pkg->size = S_EVALUATING;
+	for (i = 0; i < pkg->depends->num; i++) {
+		struct apk_dependency *dep = &pkg->depends->item[i];
+		struct apk_name *name = dep->name;
+
+		if (name->pkgs->num == 0) {
+			start_graph(ctx);
+			printf("  \"" PKG_VER_FMT "\" -> \"%s\" [color=red];\n",
+				PKG_VER_PRINTF(pkg),
+				name->name);
+			if (!(name->flags & APK_NAME_VISITED)) {
+				printf("  \"%s\" [style=dashed, color=red, fontcolor=red, shape=octagon];\n",
+					name->name);
+				name->flags |= APK_NAME_VISITED;
+			}
+		} else {
+			for (j = 0; j < name->pkgs->num; j++) {
+				struct apk_package *pkg0 = name->pkgs->item[j];
+
+				if (!apk_dep_is_satisfied(dep, pkg0))
+					continue;
+
+				r = dump_pkg(ctx, pkg0);
+				ret += r;
+				if (r || (!ctx->errors_only)) {
+					start_graph(ctx);
+					printf("  \"" PKG_VER_FMT "\" -> \"" PKG_VER_FMT "\"%s;\n",
+						PKG_VER_PRINTF(pkg),
+						PKG_VER_PRINTF(pkg0),
+						r ? "[color=red]" : "");
+				}
+			}
+		}
+	}
+	ret -= S_EVALUATING - pkg->size;
+	pkg->size = S_EVALUATED;
+
+	return ret;
+}
+
+static int foreach_pkg(apk_hash_item item, void *ctx)
+{
+	dump_pkg((struct dot_ctx *) ctx, (struct apk_package *) item);
+	return 0;
+}
+
+static int dot_main(void *pctx, struct apk_database *db, int argc, char **argv)
+{
+	struct dot_ctx *ctx = (struct dot_ctx *) pctx;
+	int i, j;
+
+	if (argc) {
+		for (i = 0; i < argc; i++) {
+			struct apk_name *name = apk_db_get_name(db, APK_BLOB_STR(argv[i]));
+			if (!name)
+				continue;
+			for (j = 0; j < name->pkgs->num; j++)
+				dump_pkg(ctx, name->pkgs->item[j]);
+		}
+	} else {
+		apk_hash_foreach(&db->available.packages, foreach_pkg, pctx);
+	}
+
+	if (!ctx->not_empty)
+		return 1;
+
+	printf("}\n");
+	return 0;
+}
+
+static struct apk_option dot_options[] = {
+	{ 0x10000,	"errors",	"Output only parts of the graph which are considered "
+					"errorneus: e.g. cycles and missing packages" },
+};
+
+static struct apk_applet apk_dot = {
+	.name = "dot",
+	.help = "Generate graphviz graphs",
+	.arguments = "PKGMASK...",
+	.open_flags = APK_OPENF_READ | APK_OPENF_NO_STATE,
+	.context_size = sizeof(struct dot_ctx),
+	.num_options = ARRAY_SIZE(dot_options),
+	.options = dot_options,
+	.parse = dot_parse,
+	.main = dot_main,
+};
+
+APK_DEFINE_APPLET(apk_dot);