[unix_api] Generate functions if their types are understood by dart:ffi (#273)

Author: brianquinlan

pkgs/unix_api/.gitattributes

@@ -4,3 +4,5 @@ lib/src/constants.g.dart linguist-generated
 lib/src/libc_bindings.g.dart linguist-generated
 src/constants.g.c linguist-generated
 src/constants.g.h linguist-generated
+src/functions.g.c linguist-generated
+src/functions.g.h linguist-generated

pkgs/unix_api/constants.json

@@ -69,5 +69,14 @@
     "DT_REG",
     "DT_SOCK",
     "DT_UNKNOWN"
+  ],
+  "<stdio.h>": [
+    "L_ctermid"
+  ],
+  "<unistd.h>": [
+    "F_OK",
+    "R_OK",
+    "W_OK",
+    "X_OK"
   ]
 }

pkgs/unix_api/ffigen.yaml

@@ -8,9 +8,11 @@ output: 'lib/src/libc_bindings.g.dart'
 headers:
   entry-points:
     - 'src/libc_shim.h'
+    - 'src/functions.g.h'
 
   include-directives:
     - 'src/libc_shim.h'
+    - 'src/functions.g.h'
 preamble: |
   // ignore_for_file: type=lint, unused_field
 comments:

pkgs/unix_api/functions.json

@@ -0,0 +1,89 @@
+{
+  "<stdio.h>" : [
+    {
+        "comment": "Renames a file.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html",
+        "prototype": "int rename(const char *, const char *)"
+    }
+  ],
+  "<string.h>" : [
+    {
+        "comment": "Formats an error code as a string.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/strerror.html",
+        "prototype": "char *strerror(int)"
+    }
+  ],
+  "<unistd.h>" : [
+    {
+        "comment": "Determines the accessibility of a file.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/access.html",
+        "prototype": "int access(const char *, int)"
+    },
+    {
+        "comment": "Schedules an alarm signal.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/alarm.html",
+        "prototype": "unsigned alarm(unsigned)"
+    },
+    {
+        "comment": "Changes the working directory.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/chdir.html",
+        "prototype": "int chdir(const char *)"
+    },
+    {
+        "comment": "Closes a file descriptor.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html",
+        "prototype": "int close(int)"
+    },
+    {
+        "comment": "Encrypts a string.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/crypt.html",
+        "prototype": "char * crypt(const char *, const char *)",
+        "available_android": false,
+        "unavailable_value": "NULL"
+    },
+    {
+        "comment": "Generates a path name for the controlling terminal.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/ctermid.html",
+        "prototype": "char * ctermid(char *)",
+        "available_android": false,
+        "unavailable_value": "\"\""
+    },
+    {
+        "comment": "Duplicates an open file descriptor.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html",
+        "prototype": "int dup(int)"
+    },
+    {
+        "comment": "Copies an open file descriptor into another.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html",
+        "prototype": "int dup2(int, int)"
+    },
+    {
+        "comment": "Determines the accessibility of a file descriptor.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/faccessat.html",
+        "prototype": "int faccessat(int, const char *, int, int)"
+    },
+    {
+        "comment": "Changes the current directory.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchdir.html",
+        "prototype": "int fchdir(int)"
+    },
+    {
+        "comment": "Forces all queued I/O operations to complete.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html",
+        "prototype": "int fdatasync(int)",
+        "available_ios": false,
+        "unavailable_value": "-1"
+    },
+    {
+        "comment": "Removes a directory entry.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/linkat.html",
+        "prototype": "int unlink(const char *)"
+    },
+    {
+        "comment": "Removes a directory entry relative to another file.",
+        "url": "https://pubs.opengroup.org/onlinepubs/9699919799/functions/unlinkat.html",
+        "prototype": "int unlinkat(int, const char *, int)"
+    }
+]
+}

pkgs/unix_api/hook/build.dart

@@ -14,7 +14,10 @@ void main(List<String> args) async {
     await CBuilder.library(
       name: packageName,
       assetName: 'libc_shim',
-      sources: ['src/libc_shim.c', 'src/constants.g.c'],
+      libraries: [
+        if ([OS.linux].contains(input.config.code.targetOS)) 'crypt',
+      ],
+      sources: ['src/libc_shim.c', 'src/constants.g.c', 'src/functions.g.c'],
       flags: ['-Weverything'],
     ).run(
       input: input,