DotTool.cpp

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#include <mutable/util/DotTool.hpp>
 
#include <mutable/util/fn.hpp>
#include <mutable/util/macro.hpp>
#include <fstream>
#include <iostream>
#include <sstream>
 
#if __linux
#include <dlfcn.h>
#include <unistd.h>
#elif __APPLE__
#include <dlfcn.h>
#include <unistd.h>
#endif
 
 
using namespace m;
 
// POD type forward declarations
struct GVC_t;
struct Agraph_t;
struct graph_t;
 
// function declarations: add the functions that you need here and to the `SYMBOLS` X macro
static int(*agclose)(Agraph_t*);
static Agraph_t*(*agmemread)(const char*);
static GVC_t*(*gvContext)();
static int(*gvFreeContext)(GVC_t*);
static int(*gvFreeLayout)(GVC_t*, graph_t*);
static int(*gvLayout)(GVC_t*, graph_t*, const char*);
static int(*gvRenderFilename)(GVC_t*, graph_t*, const char*, const char*);
 
#define SYMBOLS(X) \
    X(agclose) \
    X(agmemread) \
    X(gvContext) \
    X(gvFreeContext) \
    X(gvFreeLayout) \
    X(gvLayout) \
    X(gvRenderFilename)
 
#define LOADSYM(SYM) SYM = (decltype(SYM))(dlsym(libgraphviz, #SYM));
 
#if __linux
static constexpr const char * LIB_GRAPHVIZ = "libgvc.so";
#elif __APPLE__
static constexpr const char * LIB_GRAPHVIZ = "libgvc.dylib";
#endif
 
static void *libgraphviz;
static GVC_t *gvc;
 
DotTool::DotTool(Diagnostic &diag)
    : diag(diag)
{
    /*----- Test whether the graphviz library is available. ----------------------------------------------------------*/
#if __linux || __APPLE__
    libgraphviz = dlopen(LIB_GRAPHVIZ, RTLD_LAZY|RTLD_NOLOAD);
    if (libgraphviz == nullptr) { // shared object not yet present; must load
        libgraphviz = dlopen(LIB_GRAPHVIZ, RTLD_LAZY|RTLD_NODELETE); // load shared object
 
        if (libgraphviz) {
            /* Load the required symbols from the shared object. */
            SYMBOLS(LOADSYM);
            gvc = gvContext();
        }
    }
#endif
}
 
int DotTool::render_to_pdf(const char *path_to_pdf, const char *algo)
{
    /*----- Render the dot graph with graphviz. ----------------------------------------------------------------------*/
    auto dotstr = stream_.str();
    Agraph_t *G = M_notnull(agmemread(dotstr.c_str()));
    gvLayout(gvc, (graph_t*) G, algo);
    auto ret = gvRenderFilename(gvc, (graph_t*) G, "pdf", path_to_pdf);
    gvFreeLayout(gvc, (graph_t*) G);
    agclose(G);
    return ret;
}
 
void DotTool::show(const char *name, bool interactive, const char *algo)
{
    /* Construct filename. */
    std::ostringstream oss;
    oss << name << '_';
#if __linux || __APPLE__
    oss << getpid();
#endif
 
    /* Try to render a PDF document. */
    if (libgraphviz) {
        const std::string filename_pdf = oss.str() + ".pdf";
        if (render_to_pdf(filename_pdf.c_str(), algo))
            goto show_dot; // fall back to DOT
 
        if (interactive) {
#if __linux
            exec("/usr/bin/setsid", { "--fork", "xdg-open", filename_pdf.c_str() });
#elif __APPLE__
            exec("/usr/bin/open", { "-a", "Preview", filename_pdf.c_str() });
#endif
        } else {
            diag.out() << diag.NOTE << "Rendering to '" << filename_pdf << "'.\n" << diag.RESET;
        }
        return;
    }
 
show_dot:
    /* Fallback: emit graph as a DOT file. */
    const std::string filename_dot = oss.str() + ".dot";
    std::ofstream out(filename_dot);
    if (not out) {
        diag.err() << "Failed to generate '" << filename_dot << "'.\n";
        return;
    }
    out << stream_.rdbuf();
    out.flush();
    diag.out() << diag.NOTE << "Rendering to '" << filename_dot << "'.\n" << diag.RESET;
}