Remove Jackson dependency from exporters

exporters/common/build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
 
 description = "OpenTelemetry Exporter Common"
 otelJava.moduleName.set("io.opentelemetry.exporter.internal")
-otelJava.osgiOptionalPackages.set(listOf("com.fasterxml.jackson.core", "com.google.common.io", "io.opentelemetry.api.incubator.config", "io.opentelemetry.sdk.autoconfigure.spi"))
+otelJava.osgiOptionalPackages.set(listOf("com.google.common.io", "io.opentelemetry.api.incubator.config", "io.opentelemetry.sdk.autoconfigure.spi"))
 // sun.misc, io.grpc, and org.jspecify are not OSGi bundles and have no package versioning; must use unversioned optional.
 otelJava.osgiUnversionedOptionalPackages.set(listOf("sun.misc", "io.grpc", "org.jspecify.annotations"))
 // This bundle's exporters load sender implementations via SPI.
@@ -71,13 +71,13 @@ dependencies {
 
   // We include helpers shared by gRPC exporters but do not want to impose these
   // dependency on all of our consumers.
-  compileOnly("com.fasterxml.jackson.core:jackson-core")
   // sun.misc.Unsafe from the JDK isn't found by the compiler, we provide our own trimmed down
   // version that we can compile against.
   compileOnly("io.grpc:grpc-stub")
 
   testImplementation(project(":sdk:common"))
   testImplementation(project(":sdk:testing"))
+  testImplementation("com.fasterxml.jackson.core:jackson-core")
 
   testImplementation("com.google.protobuf:protobuf-java-util")
   testImplementation("com.linecorp.armeria:armeria-junit5")

exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/JsonEscaping.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.marshal;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+
+final class JsonEscaping {
+
+  private static final char[] HEX_DIGITS = {
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+  };
+
+  static void escapeStringTo(StringBuilder sb, String value) {
+    for (int i = 0; i < value.length(); i++) {
+      char c = value.charAt(i);
+      switch (c) {
+        case '"':
+          sb.append("\\\"");
+          break;
+        case '\\':
+          sb.append("\\\\");
+          break;
+        case '\b':
+          sb.append("\\b");
+          break;
+        case '\f':
+          sb.append("\\f");
+          break;
+        case '\n':
+          sb.append("\\n");
+          break;
+        case '\r':
+          sb.append("\\r");
+          break;
+        case '\t':
+          sb.append("\\t");
+          break;
+        default:
+          if (c < 0x20) {
+            sb.append("\\u");
+            sb.append(HEX_DIGITS[(c >> 12) & 0xF]);
+            sb.append(HEX_DIGITS[(c >> 8) & 0xF]);
+            sb.append(HEX_DIGITS[(c >> 4) & 0xF]);
+            sb.append(HEX_DIGITS[c & 0xF]);
+          } else {
+            sb.append(c);
+          }
+      }
+    }
+  }
+
+  static void escapeStringTo(byte[] buf, int[] posRef, OutputStream out, String value)
+      throws IOException {
+    for (int i = 0; i < value.length(); i++) {
+      char c = value.charAt(i);
+      String escape = null;
+      switch (c) {
+        case '"':
+          escape = "\\\"";
+          break;
+        case '\\':
+          escape = "\\\\";
+          break;
+        case '\b':
+          escape = "\\b";
+          break;
+        case '\f':
+          escape = "\\f";
+          break;
+        case '\n':
+          escape = "\\n";
+          break;
+        case '\r':
+          escape = "\\r";
+          break;
+        case '\t':
+          escape = "\\t";
+          break;
+        default:
+          if (c < 0x20) {
+            escape =
+                "\\u"
+                    + HEX_DIGITS[(c >> 12) & 0xF]
+                    + HEX_DIGITS[(c >> 8) & 0xF]
+                    + HEX_DIGITS[(c >> 4) & 0xF]
+                    + HEX_DIGITS[c & 0xF];
+          }
+      }
+      if (escape != null) {
+        writeAscii(buf, posRef, out, escape);
+      } else {
+        // Non-escape character: find the run of non-escape chars and write them as a UTF-8 chunk
+        int start = i;
+        while (i + 1 < value.length()) {
+          char next = value.charAt(i + 1);
+          if (next == '"' || next == '\\' || next < 0x20) {
+            break;
+          }
+          i++;
+        }
+        writeUtf8(buf, posRef, out, value, start, i + 1);
+      }
+    }
+  }
+
+  private static void writeAscii(byte[] buf, int[] posRef, OutputStream out, String ascii)
+      throws IOException {
+    int pos = posRef[0];
+    int len = ascii.length();
+    if (pos + len > buf.length) {
+      out.write(buf, 0, pos);
+      pos = 0;
+    }
+    for (int i = 0; i < len; i++) {
+      buf[pos++] = (byte) ascii.charAt(i);
+    }
+    posRef[0] = pos;
+  }
+
+  private static void writeUtf8(
+      byte[] buf, int[] posRef, OutputStream out, String value, int start, int end)
+      throws IOException {
+    byte[] utf8 = value.substring(start, end).getBytes(StandardCharsets.UTF_8);
+    int pos = posRef[0];
+    if (pos + utf8.length > buf.length) {
+      out.write(buf, 0, pos);
+      pos = 0;
+    }
+    if (utf8.length > buf.length) {
+      out.write(utf8);
+      posRef[0] = pos;
+      return;
+    }
+    System.arraycopy(utf8, 0, buf, pos, utf8.length);
+    posRef[0] = pos + utf8.length;
+  }
+
+  private JsonEscaping() {}
+}