refactor: use "diagram" instead of "graph"

Change everywhere to use the word "diagram" instead of "graph. Diagram
seems like the better word. It's mostly used in comments and
documentation, but there was one filename and one trait name that
needed changing.

I used "rg -iw graph" and "find -iname '*graph*'" to find everywhere
that needed changing.

Sponsored-by: author

1 files changed, 224 insertions, 0 deletions

diff --git a/src/diagrams.rs b/src/diagrams.rs
new file mode 100644
index 0000000..96f5d70
--- /dev/null
+++ b/src/diagrams.rs
@@ -0,0 +1,224 @@
+use crate::{Result, SubplotError};
+
+use std::env;
+use std::ffi::OsString;
+use std::io::prelude::*;
+use std::path::PathBuf;
+use std::process::{Command, Stdio};
+use std::sync::Mutex;
+
+use lazy_static::lazy_static;
+use structopt::StructOpt;
+
+/// Resources used to configure paths for dot, plantuml.jar, and friends
+
+#[allow(missing_docs)]
+#[derive(Debug, StructOpt)]
+pub struct MarkupOpts {
+    #[structopt(
+        long = "dot",
+        help = "Path to the `dot` binary.",
+        name = "DOTPATH",
+        env = "SUBPLOT_DOT_PATH"
+    )]
+    dot_path: Option<PathBuf>,
+    #[structopt(
+        long = "plantuml-jar",
+        help = "Path to the `plantuml.jar` file.",
+        name = "PLANTUMLJARPATH",
+        env = "SUBPLOT_PLANTUML_JAR_PATH"
+    )]
+    plantuml_jar_path: Option<PathBuf>,
+    #[structopt(
+        long = "java",
+        help = "Path to Java executable (note, effectively overrides JAVA_HOME if set to an absolute path)",
+        name = "JAVA_PATH",
+        env = "SUBPLOT_JAVA_PATH"
+    )]
+    java_path: Option<PathBuf>,
+}
+
+impl MarkupOpts {
+    /// Handle CLI arguments and environment variables for markup binaries
+    pub fn handle(&self) {
+        if let Some(dotpath) = &self.dot_path {
+            *DOT_PATH.lock().unwrap() = dotpath.clone();
+        }
+        if let Some(plantuml_path) = &self.plantuml_jar_path {
+            *PLANTUML_JAR_PATH.lock().unwrap() = plantuml_path.clone();
+        }
+        if let Some(java_path) = &self.java_path {
+            *JAVA_PATH.lock().unwrap() = java_path.clone();
+        }
+    }
+}
+
+lazy_static! {
+    static ref DOT_PATH: Mutex<PathBuf> = Mutex::new(env!("BUILTIN_DOT_PATH").into());
+    static ref PLANTUML_JAR_PATH: Mutex<PathBuf> =
+        Mutex::new(env!("BUILTIN_PLANTUML_JAR_PATH").into());
+    static ref JAVA_PATH: Mutex<PathBuf> = Mutex::new(env!("BUILTIN_JAVA_PATH").into());
+}
+
+/// A code block with markup for a diagram.
+///
+/// The code block will be converted to an SVG image using an external
+/// filter such as Graphviz dot or plantuml. SVG is the chosen image
+/// format as it's suitable for all kinds of output formats from
+/// typesetting.
+///
+/// This trait defines the interface for different kinds of markup
+/// conversions. There's only one function that needs to be defined
+/// for the trait.
+pub trait DiagramMarkup {
+    /// Convert the markup into an SVG.
+    fn as_svg(&self) -> Result<Vec<u8>>;
+}
+
+/// A code block with pikchr markup.
+///
+/// ~~~~
+/// use subplot::{DiagramMarkup, PikchrMarkup};
+/// let markup = r#"line; box "Hello," "World!"; arrow"#;
+/// let svg = PikchrMarkup::new(markup, None).as_svg().unwrap();
+/// assert!(svg.len() > 0);
+/// ~~~~
+pub struct PikchrMarkup {
+    markup: String,
+    class: Option<String>,
+}
+
+impl PikchrMarkup {
+    /// Create a new Pikchr Markup holder
+    pub fn new(markup: &str, class: Option<&str>) -> PikchrMarkup {
+        PikchrMarkup {
+            markup: markup.to_owned(),
+            class: class.map(str::to_owned),
+        }
+    }
+}
+
+impl DiagramMarkup for PikchrMarkup {
+    fn as_svg(&self) -> Result<Vec<u8>> {
+        let mut flags = pikchr::PikchrFlags::default();
+        flags.generate_plain_errors();
+        let image = pikchr::Pikchr::render(&self.markup, self.class.as_deref(), flags)
+            .map_err(SubplotError::PikchrRenderError)?;
+        Ok(image.as_bytes().to_vec())
+    }
+}
+
+/// A code block with Dot markup.
+///
+/// ~~~~
+/// use subplot::{DiagramMarkup, DotMarkup};
+/// let markup = r#"digraph "foo" { a -> b }"#;
+/// let svg = DotMarkup::new(&markup).as_svg().unwrap();
+/// assert!(svg.len() > 0);
+/// ~~~~
+pub struct DotMarkup {
+    markup: String,
+}
+
+impl DotMarkup {
+    /// Create a new DotMarkup.
+    pub fn new(markup: &str) -> DotMarkup {
+        DotMarkup {
+            markup: markup.to_owned(),
+        }
+    }
+}
+
+impl DiagramMarkup for DotMarkup {
+    fn as_svg(&self) -> Result<Vec<u8>> {
+        let mut child = Command::new(DOT_PATH.lock().unwrap().clone())
+            .arg("-Tsvg")
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()?;
+        if let Some(stdin) = child.stdin.as_mut() {
+            stdin.write_all(self.markup.as_bytes())?;
+            let output = child.wait_with_output()?;
+            if output.status.success() {
+                Ok(output.stdout)
+            } else {
+                Err(SubplotError::child_failed("dot", &output))
+            }
+        } else {
+            Err(SubplotError::ChildNoStdin)
+        }
+    }
+}
+
+/// A code block with PlantUML markup.
+///
+/// ~~~~
+/// use subplot::{DiagramMarkup, PlantumlMarkup};
+/// let markup = "@startuml\nAlice -> Bob\n@enduml";
+/// let svg = PlantumlMarkup::new(&markup).as_svg().unwrap();
+/// assert!(svg.len() > 0);
+/// ~~~~
+pub struct PlantumlMarkup {
+    markup: String,
+}
+
+impl PlantumlMarkup {
+    /// Create a new PlantumlMarkup.
+    pub fn new(markup: &str) -> PlantumlMarkup {
+        PlantumlMarkup {
+            markup: markup.to_owned(),
+        }
+    }
+
+    // If JAVA_HOME is set, and PATH is set, then:
+    // Check if JAVA_HOME/bin is in PATH, if not, prepend it and return a new
+    // PATH
+    fn build_java_path() -> Option<OsString> {
+        let java_home = env::var_os("JAVA_HOME")?;
+        let cur_path = env::var_os("PATH")?;
+        let cur_path: Vec<_> = env::split_paths(&cur_path).collect();
+        let java_home = PathBuf::from(java_home);
+        let java_bin = java_home.join("bin");
+        if cur_path.iter().any(|v| v.as_os_str() == java_bin) {
+            // No need to add JAVA_HOME/bin it's already on-path
+            return None;
+        }
+        env::join_paths(Some(java_bin).iter().chain(cur_path.iter())).ok()
+    }
+
+    // Acquire path to JAR for pandoc
+}
+
+impl DiagramMarkup for PlantumlMarkup {
+    fn as_svg(&self) -> Result<Vec<u8>> {
+        let mut cmd = Command::new(JAVA_PATH.lock().unwrap().clone());
+        cmd.arg("-Djava.awt.headless=true")
+            .arg("-jar")
+            .arg(PLANTUML_JAR_PATH.lock().unwrap().clone())
+            .arg("--")
+            .arg("-pipe")
+            .arg("-tsvg")
+            .arg("-v")
+            .arg("-graphvizdot")
+            .arg(DOT_PATH.lock().unwrap().clone())
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped());
+        if let Some(path) = Self::build_java_path() {
+            cmd.env("PATH", path);
+        }
+        let mut child = cmd.spawn()?;
+        if let Some(stdin) = child.stdin.as_mut() {
+            stdin.write_all(self.markup.as_bytes())?;
+            let output = child.wait_with_output()?;
+            if output.status.success() {
+                Ok(output.stdout)
+            } else {
+                Err(SubplotError::child_failed("plantuml", &output))
+            }
+        } else {
+            Err(SubplotError::ChildNoStdin)
+        }
+    }
+}